Question:

We are getting ready to build a house and build solar hot water heater are interesting in installing a solar PV system. Through the state and our power company we can get a rebate of about 45% on a PV system which makes the price only moderately shocking (no pun intended). You have to be on the grid to get the rebate and the power company gets to keep any extra electricity you generate. We would like to build the house to run on electricity only. In our existing house we are using an average of 1,000kWh per month. The new house will be bigger and and we will be cooking and heating the house and water using electricity instead of gas, so I know we will be using more than we are now. It seems to me we could guesstimate what we need in a new system (1,500 kWh as a start?) and add additional panels if needed. My questions (finally): 1. Is it easy to add panels to a PV system? 2. For heating water should we consider an on-demand heater like this: http://www.tankless-water-heater.com/ or should we go with an electric tank style water heater, build solar hot water heater or should we consider a solar water heating system, or a combination of the above (What happens when you run out of water with a solar water heating system. Is some sort of backup usually installed)? 3. Is running a house from a PV system even feasible? 4. Are there any websites/books/etc that you would recommend? We re building in inland Southern California and get lots of sunshine.

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First of all, don’t heat your water build solar hot water heater with PV. acuum solar hot water heater
Heat your water with solar thermal and/or gas.  Solar thermal is four times as efficient as PV for heating water.

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… We are getting ready to build a house and are interesting in installing a solar PV system.

A good time to do so. Building build solar hot water heater integrated systems can cost less than stuff added on later. Look at solar PV shingles, standing seam roof panels or other similar products. Using these on your roof you get to kill two birds with one stone. You can also design your roof and the shape of your house to optimize the solar production. Lastly, the cost of the works can be rolled into the total cost of your home and simply becomes part of your mortgage. We would like to build the house to run on electricity only.

Look really hard at this one. It can take a lot of electricity to heat water, cook food and keep the house warm. It would be cheaper, compared to the price of grid electricity, to heat and cook using something else. Since solar PV is more expensive than grid power, even with the buydowns or rebates, it’s cheaper to conserve electricity. That is, not use it in the first place. Look at gas, propane, wood pellet stoves & furnaces, corn burning stoves & furnaces, solar heating, solar cooking and the like. Some random links from googleacuum solar hot water heater

Look at solar PV shingles

That is all you should do with solar PV shingles, look at them.

acuum solar hot water heater

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The words “thin film” bother me a bit.  In one of the pictures it build solar hot water heater kind of looks like a tarp was laid on the roof. Is that how you install this stuff? How durable is it?

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The words “thin film” shouldn’t bother you any more than “crystalline”, “glass” or “electricity”. build solar hot water heater. These unisolar products are amorphous panels. They don’t use glass so they aren’t quite as fragile as other panels. They also produce a little better when hot than other types of panels but their efficiency is half that of crystalline PV. That means you’ll need twice the area for them to produce an equal amount of power. In one of the pictures it kind of looks like a tarp was laid on the roof.

This is only because the roof shingles were a different color from the PV shingles. You would get a similar effect using any two color scheme on your roofing shingles. They are not a tarp. If you chose a roof shingle with a similar color they would blend in very well. Personally, I prefer the structural standing seam roofing panels over the shingles. Is that how you install this stuff?

Installation instructions are on the website. They install in a manner similar to other roofing shingles (nailed in place using roofing nails over felt) except that they are little over 7 feet long and you need to drill a small hole through the deck for each one to feed the wires through for the electrical connection. How durable is it?

They come with a 20 year warranty and are made from steel and plastic. How durable do they need to be? They will certainly outlast a roof made from asphalt and paper.

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I think you will find the roof build solar hot water heater panels more cost effective than the shingles, if you are starting with a new roof. They are all durable, but you have to come up with the cost justification.

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I think you will find the roof panels build solar hot water heater more cost effective than the shingles…

They don’t seem that expensive, at $384 ($6/W) for the SSR-64 from solarwares.com, $5.88/W from aapspower.com, and $5.54/W from solarwindworks.com… Anyone know of better prices for the PVL-64 and -128 “field-applied roofing laminates” which come in 9′ and 18′ rolls? Unisolar’s engineering manager says he doesn’t see a guarantee problem with trickling hot water over their faces, under a layer of polycarbonate.

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Be sure to compare the installed build solar hot water heater price, unless you plan to do the work yourself.  My understanding is that the solar shingles are a lot more work to install than panels.

acuum solar hot water heater

We would like to build the house to run on electricity only.

It’s more difficult, but we did it that way. Details at www.ctaz.com/~wmbjk In our existing house we are using an average of 1,000kWh per month. The new house will be bigger and and we will be cooking and heating the house and water using electricity instead of gas, so I know we will be using more than we are now. It seems to me we could guesstimate what we need in a new system (1,500 kWh as a start?) and add additional panels if needed.

If you start from scratch, you should be able to have the same conveniences on less energy. You’ll pay extra for some of the appliances, and more care will be required in how they’re used. My questions (finally): 1. Is it easy to add panels to a PV system?

Adding additional panels isn’t a problem, especially if you allow for it in advance. 2. For heating water should we consider an on-demand heater like this:acuum solar hot water heater

We don’t have a backup. There are several days a year when we have barely warm water. It’s a PITA, but not what I’d call a hardship. I just spent the money we could have used for a tankless backup on a plasma cutter instead. On the lukewarm-water days, I’ll go out and admire the plasma cutter.  :-) YMMV 3. Is running a house from a PV system even feasible?

Absolutely. 4. Are there any websites/books/etc that you would recommend?

Start with Home Power magazine. The current issue, and many excellent articles from previous issues, are available online for free. Wayne

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2. For heating water should we consider an on-demand heater like this: http://www.tankless-water-heater.com/ or should we go with an electric tank style water heater, or should we consider a solar water heating system, or a combination of the above Up-front cost will be higher, but a solar water-heating system with a tankless backup would be ideal.

Keep in mind that where electric heating is involved, you can’t get around the fact that you pay for what you use. All a tankless/ondemand heater will save you over a electric tank storage system with an electrical backup, is the heat loss that would occur though the tank itself. Which is minimal on a high quality tank, especially if you wrap an additional layer of insulation around it. BTW, I should introduce myself. I’m Stephen, I’m a Solar Contractor and have been into Solar since 1979 (the good ‘ol tax credit days). For the past few years I’ve been concentrating on Real Estate; I’m also a Real Estate Agent. But I can’t let go of this Solar thing! It’s like an addiction.acuum solar hot water heater

Oh boy.  I knew as soon as you said “cook and heat with electricity” you’d get jumped on.  I’m with you, why mess with non-renewable resources like gas when the sun provides tons of energy for free? Unfortunately, my investigations have also shown that the traditional solar cells — battery storage — appliances as needed doesn’t work well for high-wattage items like an electric stove or heater; even if you put the money into buying enough panels and batteries to have enough power, the drawdown is so big when they are used that you’ll need to replace those expensive batteries practically every week.  (Okay, I’m exaggerating a LITTLE …)  If you’re planning to stay on-grid, not mess with batteries, and just use the solar array to reduce your electric bills, it won’t matter.  But if you’re hoping this will keep you in reliable power during brownouts and blackouts, you can either just decide to turn off the electric water heater and not use the electric stove when the grid is down, or read on for our plans.  ;) Our land in the country, where we are not living now but hope to RSN, has very reliable grid service.  However, being 15 miles out of town, I’m assuming if it ever fails it will be under the worst possible conditions, such as a blizzard or ice storm that would keep us from being able to get into town.  Reliable backup power could literally mean the difference between life and death in that case.  In addition, DH and I are both emotionally committed to replace our use of non-renewable resources with renewables as quickly and completely as possible, so we don’t want to build in anything using LP or petroleum products. My original thought was to use a wind generator to power the high-demand appliances.  I’ve been told that won’t work well because you can’t channel the wind-produced AC right into a house AC system.  I still don’t understand why but since EVERYONE knowledgable has given me the same answer, I have to assume they are probably right. So our current plans, when we build, are to use everything renewable we can — belt and suspenders, so to speak.  Big south-facing windows and lots of thermal mass to minimize heating needs.  (Believe it or not, we get so much sun here in windy Wyoming that the plants in my big south-facing living room window do fine all winter, even when it’s 20 below outside!)  Some kind of heating stove that will burn renewables: haven’t decided between wood (scarce around here) or corn or #2 heating oil (which is interchangeable with diesel, more on that later).  A fan system to move the warm air from the heating stove around the house. Some kind of water reservoir in or around the heater with a tankless electric heater near where hot water is needed.  Lots of cooking alternatives, including my crockpot, microwave, steamer, and a solar oven built into the south wall, besides the electric stove.  And a diesel generator to supply the high-wattage power needed for electric stove and water heater. Why diesel and #2 home heating oil, when I made it clear we didn’t want to be dependent on ANY non-renewable energy sources?  Because biodiesel can be substituted for either regular diesel or #2 oil.  Biodiesel sounds absolutely wonderful and feasible for us to make on our own; we’re currently hunting for a super-cheap old diesel vehicle so we can see if we can make our own fuel before spending big bucks on a newer diesel to be our main car.  Assuming we are able to establish a regular source of waste vegetable oil (WVO), process it into biodiesel ourselves, and store it safely until needed, we should be able to meet our housing and mobility needs with no use of nonrenewable resources! Wheeeee! — Sylvia Steiger RN BS http://www.SteigerFamily.com Cheyenne WY, USDA zone 5a, Sunset zone 1a Home of the Wyoming Wind Festival, January 1-December 31

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Oh boy.  I knew as soon as you said “cook and heat with electricity” you’d get jumped on.  I’m with you, why mess with non-renewable resources like gas when the sun provides tons of energy for free?

Energy from the sun may be free but the hardware to capture it, convert it, store it and so forth sure aren’t.  :) But that is your call. Unfortunately, my investigations have also shown that the traditional solar cells — battery storage — appliances as needed doesn’t work well for high-wattage items like an electric stove or heater; even if you put the money into buying enough panels and batteries to have enough power, the drawdown is so big when they are used that you’ll need to replace those expensive batteries practically every week.  (Okay, I’m exaggerating a LITTLE …)

Uhmmmmm,,, no, a person just needs to properly size the number of panels/batteries/inverters/wiring and so forth to match the load, even if it is a high wattage load(s). Conclusion: with the proper sized panels/batteries and so forth, a person could run *all* the high-wattage appliances they want.  Just takes money. Lots of money.  If you’re planning to stay on-grid, not mess with batteries, and just use the solar array to reduce your electric bills, it won’t matter.  But if you’re hoping this will keep you in reliable power during brownouts and blackouts, you can either just decide to turn off the electric water heater and not use the electric stove when the grid is down, or read on for our plans.  ;) Our land in the country, where we are not living now but hope to RSN, has very reliable grid service.  However, being 15 miles out of town, I’m assuming if it ever fails it will be under the worst possible conditions, such as a blizzard or ice storm that would keep us from being able to get into town.  Reliable backup power could literally mean the difference between life and death in that case.

You could simplify your plan by just having a backup wood stove to provide heat and a coleman type camp stove/lantern and a few cans of beans when it is storming outside and grid power is interupted.  This setup is a tried and true method that has been used by lots of settlers before you in Wyoming/Montana and elsewere while raging blizzards and sub-sub zero temperatures are occuring outside.  So how long does grid power go out where you propose to live and for how long?  :)   In addition, DH and I are both emotionally committed to replace our use of non-renewable resources with renewables as quickly and completely as possible, so we don’t want to build in anything using LP or petroleum products. My original thought was to use a wind generator to power the high-demand appliances.  I’ve been told that won’t work well because you can’t channel the wind-produced AC right into a house AC system.  I still don’t understand why but since EVERYONE knowledgable has given me the same answer, I have to assume they are probably right.

You would have to channel the DC power from the windmill to your batteries, then through the inverter and then into your AC appliances. So our current plans, when we build, are to use everything renewable we can — belt and suspenders, so to speak.  Big south-facing windows and lots of thermal mass to minimize heating needs.  (Believe it or not, we get so much sun here in windy Wyoming that the plants in my big south-facing living room window do fine all winter, even when it’s 20 below outside!)

Of course your plants do well, it is 70 degrees inside the house and they get all the sunlight they want  Some kind of heating stove that will burn renewables: haven’t decided between wood (scarce around here) or corn or #2 heating oil (which is interchangeable with diesel, more on that later).

Corn is scarce too in Wy, but easy enough to get in Northern Colorado, which isn’t to far away from Cheyenne.  How many miles would it be to truck some in? A fan system to move the warm air from the heating stove around the house. Some kind of water reservoir in or around the heater with a tankless electric heater near where hot water is needed.  Lots of cooking alternatives, including my crockpot, microwave, steamer, and a solar oven built into the south wall, besides the electric stove.  And a diesel generator to supply the high-wattage power needed for electric stove and water heater.

Good plan.  Have you given it any thought on how to keep  your diesel/bio-diesel from jellying in the tank(s) when it gets below zero?  As in 0, -20,-30,-50 degrees F? Which occurs a number of times each winter?   I understand bio-diesel is really touchy in cold temperatures. Why diesel and #2 home heating oil, when I made it clear we didn’t want to be dependent on ANY non-renewable energy sources?  Because biodiesel can be substituted for either regular diesel or #2 oil.  Biodiesel sounds absolutely wonderful and feasible for us to make on our own; we’re currently hunting for a super-cheap old diesel vehicle so we can see if we can make our own fuel before spending big bucks on a newer diesel to be our main car.  Assuming we are able to establish a regular source of waste vegetable oil (WVO), process it into biodiesel ourselves, and store it safely until needed, we should be able to meet our housing and mobility needs with no use of nonrenewable resources!

Then you will need a truck of some sort to haul all the barrels that will contain the used cooking frier oils from fast food/restraunts back to your homestead for processing.    You mentioned possible getting a diesel powered “car”.  Perhaps you may want to think diesel powered PU. Kill two birds with one stone.  BTW, have you ever tried starting a diesel engine when it has been sitting out in temperatures overnight of minus 10 F (or lower) ? Ugly, You will be also competing with whomever else has the same ideas as you about making less expensive biodiesel.  As far as storing it *safely*?  Hope you store it far away from the main living quarters because it is very flammable.  Just like storing barrels of gasoline  next to your house.  Once the fuel source gets ignited (by whatever means) , it then becomes a potential powder keg.  Then you have the smell, fumes, spillage and contamination from handling it  to content with.  But it is free. Wheeeee!

Wheee is right!  Can be fun and entertaining.  Good luck

Response:

…my investigations have also shown that the traditional solar cells — battery storage — appliances as needed doesn’t work well for high-wattage items like an electric stove or heater; even if you put the money into buying enough panels and batteries to have enough power, the drawdown is so big when they are used that you’ll need to replace those expensive batteries practically every week.  (Okay, I’m exaggerating a LITTLE …)

Trojan batteries are rated for total “lifetime energy storage.” They wear out after say, 1000 100% charge-discharge cycles or 2000 50% cycles, and so on, approximately. They actually store more lifetime energy with fewer and deeper discharges, eg 30% vs 5%, and they have a finite shelf life, even if never discharged. You need more batteries to store the same amount of energy with shallower discharges, and batteries take up space and up-front and ongoing money. Most PV people tend to overpopulate and underdischarge batteries in an uneconomical way. Our land in the country, where we are not living now but hope to RSN, has very reliable grid service.  However, being 15 miles out of town, I’m assuming if it ever fails it will be under the worst possible conditions, such as a blizzard or ice storm that would keep us from being able to get into town. Reliable backup power could literally mean the difference between life and death in that case.

You might have just a few batteries, say enough for 12 hours for critical loads, and a generator to charge them or operate critical loads by itself if needed. That gives triple redundancy: grid, batteries, and generator. My original thought was to use a wind generator to power the high-demand appliances.  I’ve been told that won’t work well because you can’t channel the wind-produced AC right into a house AC system.  I still don’t understand why but since EVERYONE knowledgable has given me the same answer, I have to assume they are probably right.

I wouldn’t write off wind power quickly, if you have wind. It’s cheaper than PV, closer to $1 than $5 per peak watt, especially with a tree or a barn for a tower, and it can work on cloudy days or at night. It does require more maintenance than PVs. You might either get a small DC turbine and use an inverter, or get a larger one with an AC induction motor which can match grid power if present and match your inverter if not. Or maybe make “wild AC” and rectify that to make DC. This can be more efficient than a 60 Hz system, with a varying vs fixed prop speed. So our current plans, when we build, are to use everything renewable we can — belt and suspenders, so to speak.  Big south-facing windows and lots of thermal mass to minimize heating needs.

I’d suggest “lots of insulation,” eg a house built with Structural Insulated Panels (SIPs), ie glued plywood-foamboard-plywood sandwiches. Water can be excellent thermal mass, cheaper and more compact than masonry, storing 3X more heat by volume, easy to insulate and move around, fairly easy to heat with the sun. Big south windows can lose lots of heat at night and on cloudy days. Part of the south wall could be simple thermosyphoning air heaters which lose no heat at night, or you might supply daytime heat for the house from a low-thermal-mass sunspace. You might have a hydronic slab and trickle warm water between a dark metal roof and a single layer of polycarbonate greenhouse roofing (eg “Dynaglas”) over that, with a higher temp heat store for cloudy days. Part of the metal roof might be covered with Unisolar PV “field-applied roofing laminate,” with water trickling over that. And a diesel generator to supply the high-wattage power needed for electric stove and water heater.

Start the diesel whenever you want to make a cup of tea? You might heat water or the house with its “waste heat,” which might be 80% of the fuel’s heating value… …Biodiesel sounds absolutely wonderful and feasible for us to make on our own… Assuming we are able to establish a regular source of waste vegetable oil (WVO), process it into biodiesel ourselves, and store it safely until needed, we should be able to meet our housing and mobility needs with no use of nonrenewable resources!

Sounds like more ongoing work than sun and wind power.  And less independent, with this “regular source” requirement. And you will be adding CO2 to the atmosphere. Nick

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My original thought was to use a wind generator to power the high-demand appliances.  I’ve been told that won’t work well because you can’t channel the wind-produced AC right into a house AC system.  I still don’t understand why but since EVERYONE knowledgable has given me the same answer, I have to assume they are probably right.

Don’t understand this.  If you’re on grid, you can take advantage of Wyomings’ net metering law, which even calls for utility purchase of annual excess wind energy at avoided cost. Off-grid, you would depend on batteries.  As others point out, your occasional off-grid dependence on (wind and) batteries and their 1000 or so discharge cycles for your “high-demand applicances” (the use of which would be curtailed during an emergency, one would think), would not guarantee a weekly battery replacement, or even yearly.  Maybe 5-yearly to 8-yearly, depending on what you buy and how you maintain it. You need a 48-V DC 7.5 kW wind turbine/controller (Bergey), 18 grand, a pair of Xantrex SW 4-kW inverters (with GTI), 6 grand, a 7.5 kW dump load (heater/water heater) for dumping excess energy during off-grid operation, ? grand, and between 100 and 750 Ah (at 48 VDC) of batteries, 1 grand to 6 grand, depending on how often and how long you expect to put up with grid outages. If your annual average wind speed is 12 mph or higher, you can expect that turbine to produce 15,000 kWh annually, or more.  The purchase of annual excess energy guranteed by Wyoming’s excellent net metering law makes this system more attractive to people in your situation than in most of the other net metering states, where excess energy is donated to the utility.

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You need a 48-V DC 7.5 kW wind turbine/controller (Bergey), 18 grand, a pair of Xantrex SW 4-kW inverters (with GTI), 6 grand, a 7.5 kW dump load…

I still don’t get it. Why do wind turbines need dump loads? Why not just operate them closer to stall speed? Nick

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You need a 48-V DC 7.5 kW wind turbine/controller (Bergey), 18 grand, a pair of Xantrex SW 4-kW inverters (with GTI), 6 grand, a 7.5 kW dump load (heater/water heater) for dumping excess energy during off-grid operation, ? grand, and between 100 and 750 Ah (at 48 VDC) of batteries, 1 grand to 6 grand, depending on how often and how long you expect to put up with grid outages.

Although using excess energy build solar hot water heater during off-grid operation is not a bad thing, with the setup you describe there is no requirement for a dump load.  The Bergey is designed to run unloaded. — ron  (off the grid in Downeast Maine)

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Although using excess energy during off-grid operation is not a bad thing, with the setup you describe there is no requirement for a dump load.  The Bergey is designed to run unloaded.

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Why does any wind turbine need a diversion load, with an MPPT that can load it to limit power?

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Why does any wind turbine need a diversion load, with an MPPT that can load it to limit power?

build solar hot water heater, I don’t understand much about MPPT — how does it work with a wind turbine, and how would that obviate the need for a dump load (for those turbines that require one).

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Conclusion: with the proper sized panels/batteries and so forth, a person could run *all* the high-wattage appliances they want.  Just takes money. Lots of money.

I guess I should have specified that it wasn’t a realistic option unless they have more money to throw at it than I do! You could simplify your plan by just having a backup wood stove

No readily-available wood unless we buy it and keep it on hand.  Whereas I hope we WILL have biodiesel stored on-site to run an oil heater. So how long does grid power go out where you propose to live and for how long?  :)

As I said, I don’t know that it has build solar hot water heater.  I’m just planning for a worst-case emergency. Of course your plants do well, it is 70 degrees inside the house and they get all the sunlight they want

Do you do much gardening?  The participants on the gardening newsgroups frequently discuss the need for additional light for indoor plants during the winter because they suffer during short, cloudy days.  Since they agree my high amount of sunlight is exceptional, your comment seems rather ignorant. Good plan.  Have you given it any thought on how to keep  your diesel/bio-diesel from jellying in the tank(s) when it gets below zero?

Of course.  That is a problem we’ll have to face for vehicles as well. We haven’t decided on a system yet but it will be included. I understand bio-diesel is really touchy in cold temperatures.

My research is that it isn’t any less likely to jell than petrodiesel … but it isn’t any less likely, either.  :( Then you will need a truck of some sort

Not just for hauling WVO!  Believe me, I already wish we had a pickup. But my immediate priority is anything diesel and cheap; no point in spending the bucks for a nice diesel PU if it turns out we can’t manage to make our own biodiesel. Hope you store it far away from the main living quarters because it is very flammable.  Just like storing barrels of gasoline  next to your house.

Have you ever actually looked into this?  Diesel is NOT as flammable as gasoline.  Sure it needs to be stored appropriately, and not in a living room, but hundreds of thousands of people are managing to do so, and I’m confident we can also.

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I don’t understand much about MPPT — how does it work with a wind turbine,

You can think of it as “impedance matching for maximum power transfer.” If you push on a boxcar, it won’t move, with no useful human power output: a large force times zero velocity equals zero power. If you push on a feather, you and it will move so easily that there won’t be any useful human power either, with a large velocity but close to zero force. You can maximize your useful power output by pushing on something between, eg a car, if you feel strong, or a wheelbarrow or wagon, if you are tired. Here’s a wind interpretation: connect a large load (a small resistor) to a wind generator, and the blades won’t turn much. They will be aerodynamically stalled, and the generator won’t produce build solar hot water heater much electrical power. Connect a small load (a large resistor) and the blades spin fast and the generator produces a large voltage but little current, with little useful power.   and how would that obviate the need for a dump load (for those turbines that require one).

As windspeeds increase, increase the load on the generator to limit the rpm and power output to some maximum value, ie make the wind turbine operate less efficiently. This isn’t MPPT, but it can be done with the same hardware…

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Conclusion: with the proper sized panels/batteries and so forth, a person could run *all* the high-wattage appliances they want.  Just takes money. Lots of money. I guess I should have specified that it wasn’t a realistic option unless they have more money to throw at it than I do!

I know.  It is rather difficult to respond to some of these financial issues because one doesn’t know the persons porfolio.  After I punched the send key on the last message, I thought that wouldn’t it be funny if you were a Bill Gates clone and what I said wouldn’t have mattered because a Bill Gates clone could afford any kind of PV system he wanted to power whatever high wattage load he wanted with just his pocket change.  :) You could simplify your plan by just having a backup wood stove No readily-available wood unless we buy it and keep it on hand.  Whereas I hope we WILL have biodiesel stored on-site to run an oil heater.

In a *strict* emergency only build solar hot water heater situation , a free standing,  non nonsense, no electric fan driven wood stove would be ideal.  Buy a cord of wood and have it sitting on standby. Most economical scenario for emergency heating. Which was the thought?   All the oil burner heating stoves that I know of require electricity to operate the pump, fan, thermostat and such.  Now if you are talking a diesel/gas powered generator in conjunction with the oil burner, then that’s a doable combination.  Considered a pellet stove?  You could haul the commercial processed pellets from WalMart  in the back of your future PU. – Hide quoted text — Show quoted text – So how long does grid power go out where you propose to live and for how long?  :) As I said, I don’t know that it has.  I’m just planning for a worst-case emergency. Of course your plants do well, it is 70 degrees inside the house and they get all the sunlight they want Do you do much gardening?  The participants on the gardening newsgroups frequently discuss the need for additional light for indoor plants during the winter because they suffer during short, cloudy days.  Since they agree my high amount of sunlight is exceptional, your comment seems rather ignorant.

You didn’t specify what kind of plants.  We have plants, people in the drizzly rainforest of western Oregon (cloud free days in the winter are a rarity)  had/have house plants, everyone I know of have some sort of house plants and no one that I know of has supplementary artificial lights. Wyoming has plenty of cloud free days.  Different variety of house plants need different amounts of lights ( to the point of too much sunlight is detrimental to its survival) and whatever variety I’ve seen must not have been to picky.  In conclusion, whatever variety you are interested in must need more light.  Do you garden by committee since you base your gardening knowledge from what  newsgroups say?  Or are we discussing eatable vegetable type plants that you choose to grow indoors? Good plan.  Have you given it any thought on how to keep  your diesel/bio-diesel from jellying in the tank(s) when it gets below zero? Of course.  That is a problem we’ll have to face for vehicles as well. We haven’t decided on a system yet but it will be included.

What system? Either you run a winter blend (petroleum based diesel) or you don’t(vehicle application here) .  You can add an anti-jellying additive to #2Diesel that gets you down to ~-10F before jellying.  When you are talking real cold, then straight #1 is the ticket.   Then you need to figure out how to even crank over the diesel motor when it has been sitting out in subzero temperatures for the afternoon/night with 15w-40 motor oil in the crankcase and it acts like 120w.  Electric engine block heaters, battery warmers and such that draw 1500watts plus are the common solution.  Good idea to plug in your car for numerous hours before needing to start it.  Good idea even for gas burners when temperatures get that low.  We are talking the extreme emergency situation still aren’t we?  You will see these conditions several times a winter.  I know, I have lived in Wyoming before.  Great state, great bunch of people.  Got your Carhartt polar insulated coveralls and Pak Boots purchased?  :) I understand bio-diesel is really touchy in cold temperatures. My research is that it isn’t any less likely to jell than petrodiesel …

but it isn’t any less likely, either. Don’t know for sure about bio-diesels cold temperature characteristics. Hate build solar hot water heater to bet my life on it but it may be the cats meow. Then you will need a truck of some sort Not just for hauling WVO!  Believe me, I already wish we had a pickup. But my immediate priority is anything diesel and cheap; no point in spending the bucks for a nice diesel PU if it turns out we can’t manage to make our own biodiesel.

PU is still real handy when you have to haul building materials to the homestead. Hay for the future pony.   Makes sense to get a diesel for the fuel economy,  less pollution (than gas)  and so forth, even if you end up not burning bio-diesel in it.  4×4  PU’s are real handy to bust through the snow drifts going home, where a car would get stuck.   Did I mention  I can tell you are not a native of Wyoming.  <g  PU’s rule in Wyoming (cowboy Cadillac) and the preferred mode of transportation (by natives) .  Gotta get the big Wyoming mud flaps too.  <g  Don’t forget to get the big honken oil field special grill guard to protect yourself from suicidal antelope/deer/out_of_state_compact_cars.  Careful about the “anything diesel and cheap”.  Could end up with one of those 70’s GM  6.2lL want-to-be diesel cars. Get a PU of any shape size or description, then you will have to start defending it to all the city folks  who advocate mini-cars on the newsgroups.  :(  You will also get the glaring looks (if you are driving a PU w/Wyoming plates) when you travel to Denver as you go past Boulder. Hope you store it far away from the main living quarters because it is very flammable.  Just like storing barrels of gasoline  next to your house. Have you ever actually looked into this?  Diesel is NOT as flammable as gasoline.

Key word is “NOT as”.  Flash/vapor point of diesel is a bit higher than gas but still very flammable.  Yes, I’ve looked into it and work around petroleum products nearly all my adult life.   Have you ever tried putting out a five gallon diesel spill fire? Let alone a drum or two full of it?  I was thinking in your enclosed garage where vapors and spillage could collect and you are thinking (guess here)  in a 250gallon tank beside the house like they do in the East.  OK.  Sure it needs to be stored appropriately, and not in a living

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For my house during the summer time we only use 215 KWh per month, and we have an electric water heater and stove.  At some point I plan on getting a grid-tied system that will equal this. Then I don’t have to worry about any utility bills at all.  I see where you are coming from.  I want to be as self sufficient as possible.

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A few recommendations from a neighbor from the North. I don’t know build solar hot water heater how USA rates home insulation efficiency but I know Canada recommends builders to build homes that meet the R2000 standard. Maybe a search in Google will bring up more information on this standard. Now just recently, I was watching the Discovery Channel and saw a profile on a couple who built a Victorian style home that was 30% more efficient than a R2000 home. This is quite impressive and it pays for itself in a short time frame. The windows he mentions are fairly new technology and I know that at least Kohler (http://www.kohler-windows.com/) makes them. You can see a video clip on this by going to Discovery’s website at www.exn.ca You will have to search for “energy home” and click on the first search result returned. You’ll need Windows media player to view it. I also saw another program from this channel where a guy in Toronto built a house in the city without hooking up to the city services. He collected his water from rain, treated it, and stored it in tanks. His waste water was treated within the house and reused for non-hygienic related items such as washer, dishwasher and toilet. Excess water would just be discharged into the garden. His electricity came from solar panels. The house was designed to get the most of the heat from the sun. Unfortunately, Discovery’s website doesn’t have this clip available. Maybe I was dreaming this If you go to www.homepower.com , you’ll see an article on using solar water panels to heat up your household water. Personally, I feel this is the way to go for heating water. You’ll still need a second water heater to pick up the slack on those cold windy days. My next approach would be to pick a proper combination of solar and wind power. (Hydro generators too if possible) The first thing to realize is that it is cheaper to save power than it is to produce it. The second thing would be to understand your energy requirements on a yearly, monthly, daily, and hourly basis. Then determine what combination of RE generating devices will match your power requirements. Solar energy has the advantage that it produces it when you need it. In the daytime. It doesn’t work too well on a cloudy day and that’s where wind power comes in. Wind and clouds generally go hand in hand. At least where I live so the two are a good match. The next phase would be to have a proper back up when the solar and wind fail. The power company, a fueled generator, or battery backup are some of the options. At this stage of the game, costs, maintenance, reliability, location, and many other factors come into play. But I’m sure a little more research will reward you with some feasible designs. You never know, you might make some money by selling power back to the grid. The technology is there and waiting to be used. If only government and the power companies would encourage it. But that’s another topic. Hope all goes well. I’m definitely not an expert on the topic so I really want some feedback since I’ve only been research home energy for a couple of weeks now. I will also be building a house sometime in the near future.

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Start the diesel whenever you want to make a cup of tea? Naaaah, the microwave will be fine for that.  But I’ll probably run the genset when I’m cooking dinner and using the stove and two burners.  ;)

Is this going to be a  solar  or wind powered microwave? And you will be adding CO2 to the atmosphere. Only what the plants took out of the atmosphere originally — one of the

big advantages of biodiesel is the zero net CO2. I have a problem with the assumption that by burning biodiesel, you get a nett zero CO2. This will only happen if the ground on which the diesel plants are cultivated, remains bare if some other fuel is used. If this ground it is cultivated with any plant for whatever use, the addition to the CO2 production will remain much the same as for petrodiesel, or do I have it wrong?

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I am really curious how it “pays for itself in a short time frame”.  I hear this all the time from people advocating additional insulation and such, but I no longer believe it based on my own experience. I pay about $600 a year for gas heat.   I have an average size house (3br, 2 bath ranch). If I were to put in an attic blanket, I’d get maybe a 10-20% reduction in heat loss, but the cost would be in excess of $1000 for the insulation build solar hot water heater. You never really recover enough money in savings to justify the added cost.

Hi Bob, I assume you’re just pulling numbers out of the air, but let’s go with the numbers you gave here.  A 10-20% reduction in fuel cost would mean $60 to $120 per year.  So, just figuring simple payback, it would take between about 8 and 17 years to recover your money.  I sure hope most houses will last much longer than that. I recently spent a rather unpleasant day crawling around the attic of our new (old) house, adding R20 to the existing spotty R12 insulation.  Cost me $500.  I don’t know how much money it will save me, but it was definitely worth doing (though I sure didn’t enjoy it!).

I am really curious how it “pays for itself in a short time frame”.  I hear this all the time from people advocating additional insulation and such, but I no longer believe it based on my own experience. I pay about $600 a year for gas heat.   I have an average size house (3br, 2 bath ranch). If I were to put in an attic blanket, I’d get maybe a 10-20% reduction in heat loss, but the cost would be in excess of $1000 for the insulation. You never really recover enough money in savings to justify the added cost.

Insulation and conservation methods work on the rule of diminishing returns. Your heating bill is already pretty good so you must already have some insulation/conservation techniques in play. But as I said, it follows the laws of dimishing returns.  If your heating bill were $280/month, a thousand dollar investment that saves $100/month could pay off in just a couple of heating seasons.    But the second thousand dollar investment would *not* save an additional $100/month.  Might only save $60.  And the third thousand dollar investment might only save $15/month and would take more than 16 heating seasons. Even if each time you put insulation in the attic you were to double the insulation already there, you would never get the heating bill to zero.  And the cost of doubling the insulation would, of course, double each time you did it.

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Even if each time you put insulation in the attic you were to double the insulation already there, you would never get the heating bill to zero…

Au contraire. You would, if you used any electricity in the house. Nick

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Even if each time you put insulation in the attic you were to double the insulation already there, you would never get the heating bill to zero… Au contraire. You would, if you used any electricity in the house.

I beg to differ.  If the house conforms to common building codes, it will have windows amounting to 10 percent of its floor area. Since these will rarely have an R value in excess of 4, incidental heating is unlikely to bring the required makeup heating needed to counter loss through the windows to zero in any climate where people would consider adding lots of insulation to the attic.acuum solar hot water heater

No readily-available wood unless we buy it and keep it on hand.  Whereas I hope we WILL have biodiesel stored on-site to run an oil heater.

If you have bio-diesel I ASSume you have some oil crop.   Why not just burn the crop for heat?   What’s to gain by processing out the bio-diesel?   (I have NEVER seen bio-diesel realistically priced at less than petro-diesel and usually it is about twice petro-diesel.)   Burning corn, for example, as fuel can be cost effective under certain circumstances.

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Even if each time you put insulation in the attic you were to double the insulation already there, you would never get the heating bill to zero… Au contraire. You would, if you used any electricity in the house. I beg to differ.

OK. I agree with you. If the house conforms to common building codes, it will have windows amounting to 10 percent of its floor area.

I’d say 8%, or maybe 4%… Since these will rarely have an R value in excess of 4, incidental heating is unlikely to bring the required makeup heating needed to counter loss through the windows to zero in any climate where people would consider adding lots of insulation to the attic.

Weasel words… Attic insulation alone may not do it. A friend who squeezed foam insulation board into most of his window frames has very low heating bills… Say we caulk up an A ft^2 square 1-story house really tight to make 0.2 Air Changes per Hour. If it has R48 SIP walls and ceiling and R10 foamboard (2″ of Styrofoam, or thinner double-foil foam) in most of the windows, its conductance will be 0.08A/R14 for windows plus A/48 for ceiling plus 0.2×8A/55 for air leaks plus (8×4sqrt(A)-0.08A)/48 for walls, ie G = 0.05397A+0.66666sqrt(A) Btu/h-F. If half of the windows face south, with 50% solar transmission, and they collect 500 Btu/ft^2 of sun on an average 30 F January day in Phila and lose 6h(75-30)/R4 = 68 Btu/ft^2-day (when warm air between the foamboard and the window rises up and escapes into the room through small holes near the top of the foamboard), and the internal electrical usage is 600 kWh/mo (68K Btu/day), and the daily heat gain E = 68K+17.3A = 24h(65-30)G = 840G, A = 1,627 ft^2, a small house. How big could it be with R20 windows? Nick

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A friend who squeezed foam insulation board into most of his window frames has very low heating bills… I presume you refer to night shading here rather than permanently blocking windows.

Well, maybe he unblocks the north windows in summertime. Say we caulk up an A ft^2 square 1-story house really tight to make 0.2 Air Changes per Hour. If it has R48 SIP walls and ceiling and R10 foamboard (2″ of Styrofoam, or thinner double-foil foam) in most of the windows, its conductance will be 0.08A/R14 for windows plus A/48 for ceiling plus 0.2×8A/55 for air leaks plus (8×4sqrt(A)-0.08A)/48 for walls, ie G = 0.05397A+0.66666sqrt(A) Btu/h-F. I presume you meant to use R4 windows here.

The R10 board is inside the R4 window. If half of the windows face south, with 50% solar transmission, and they collect 500 Btu/ft^2 of sun on an average 30 F January day in Phila and lose 6h(75-30)/R4 = 68 Btu/ft^2-day (when warm air between the foamboard and the window rises up and escapes into the room through small holes near the top of the foamboard), and the internal electrical usage is 600 kWh/mo (68K Btu/day), and the daily heat gain E = 68K+17.3A = 24h(65-30)G = 840G, A = 1,627 ft^2, a small house. How big could it be with R20 windows? …with R20 windows, I doubt you would be getting 50% solar transmission.

This might work better with R1 windows with 90% solar transmission and R20 foamboard inside. With 0.08A/R24 for windows plus A/48 for ceiling plus 0.2×8A/55 for air leaks plus (8×4sqrt(A)-0.08A)/48 for walls, G = 0.051591A+0.66666sqrt(A) Btu/h-F. On an average day, a square foot of window might collect 900 Btu and lose 6h(75-30)/R1 = 270, for a 630 Btu net gain… 68K+630×0.04A = 24(65-30)G makes A+30.88sqrt(A)-3760 = 0, and substituting B = sqrt(A) in the quadratic formula makes B = 47.79, so A = 2284 ft^2. Better… …I would like to know where to get reliably R4 windows with transmission that high.

Gathering that kind of data is difficult. (The vendors I have found provide no guarantees on the lifetime of argon fill.)

You might do almost as well with low E-hardcoat. I also wonder why you use a 6 hour shaded period.  I think the winter nights are much longer than that in North America.

That’s an estimate for the average daily solar collection period in January in Phila. Finally, I’d sure love to get my electricity usage down to 600 kWh per month.

Steve Baer uses 80.acuum solar hot water heater

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Even if each time you put insulation in the attic you were to double the insulation already there, you would never get the heating bill to zero… Au contraire. You would, if you used any electricity in the house. I beg to differ. OK. I agree with you.

Thanks, that’s refreshing. If the house conforms to common building codes, it will have windows amounting to 10 percent of its floor area. I’d say 8%, or maybe 4%…

Yes.  The 10% requirement is only for certain rooms of a house, so my figure overstates the necessary window area. Kitchens, bathrooms and closets will usually have less, especially in a house designed for thermal economy. Since these will rarely have an R value in excess of 4, incidental heating is unlikely to bring the required makeup heating needed to counter loss through the windows to zero in any climate where people would consider adding lots of insulation to the attic. Weasel words… Attic insulation alone may not do it.

Try to be polite, Nick.  I’m only trying to exclude climates with so little need for heating that incidental heating would be enough without any heroic effort. A friend who squeezed foam insulation board into most of his window frames has very low heating bills…

I presume you refer to night shading here rather than permanently blocking windows. Say we caulk up an A ft^2 square 1-story house really tight to make 0.2 Air Changes per Hour. If it has R48 SIP walls and ceiling and R10 foamboard (2″ of Styrofoam, or thinner double-foil foam) in most of the windows, its conductance will be 0.08A/R14 for windows plus A/48

for ceiling plus 0.2×8A/55 for air leaks plus (8×4sqrt(A)-0.08A)/48 for walls, ie G = 0.05397A+0.66666sqrt(A) Btu/h-F.

I presume you meant to use R4 windows here. If half of the windows face south, with 50% solar transmission, and they collect 500 Btu/ft^2 of sun on an average 30 F January day in Phila and lose 6h(75-30)/R4 = 68 Btu/ft^2-day (when warm air between the foamboard and the window rises up and escapes into the room through small holes near the top of the foamboard), and the internal electrical usage is 600 kWh/mo (68K Btu/day), and the daily heat gain E = 68K+17.3A = 24h(65-30)G = 840G, A = 1,627 ft^2, a small house. How big could it be with R20 windows?

Well, with R20 windows, I doubt you would be getting 50% solar transmission.  In fact, I would like to know where to get reliably R4 windows with transmission that high.  (The vendors I have found provide no guarantees on the lifetime of argon fill.) I also wonder why you use a 6 hour shaded period.  I think the winter nights are much longer than that in North America. Finally, I’d sure love to get my electricity usage down to 600 kWh per month.

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Finally, I’d sure love to get my electricity usage down to 600 kWh per month.

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That should have been ‘January usage’. Really?  Do you heat your house with electricity?

No, but the electric clothes dryer gets used a lot during the rainy season here. We live a pretty normal life in our house, and use about 7KWh/day (210KWh per month).  Maybe you’re averaging in summer air conditioning?

Nope. We don’t use our air conditioner (silly thing came with the house — anybody want to buy a hardly used central air conditioner near Kitchener-Waterloo in Ontario, Canada?).

After installing a light colored roof, we hardly think of wanting any AC.

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Finally, I’d sure love to get my electricity usage down to 600 kWh per month. That should have been ‘January usage’. Really?  Do you heat your house with electricity? No, but the electric clothes dryer gets used a lot during the rainy season here.

Ah, that would take a big chunk.  I’m blessed with a wife who doesn’t mind hanging the laundry build solar hot water heater to dry, indoors or outdoors, depending on the weather. We live a pretty normal life in our house, and use about 7KWh/day (210KWh per month).  Maybe you’re averaging in summer air conditioning? Nope.

We have replaced all our commonly used light bulbs with compact fluorescents.  We also heat primarily with a wood stove, so no power to run any big furnace blower.  And we have a gas water heater — makes a big difference.  In our old house with an electric hot water heater we used to run about 15K-18Wh/day. We do still cook with an electric range, though I hope to install a gas range soon.

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Well, all depends.  Do you wnat ac?  You’d be better off with a solar water heater than electric, solar panels are, what, 15% efficient? Will the electric company pay you for extra power, or do they just get to keep it.  If the latter, they are probably going to have a say-so in the size.  Also, you are going to need many panels if you plan to use ac and size it to the peak demand.

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Well, all depends.  Do you wnat ac?  You’d be better off with a solar water heater than electric, solar panels are, what, 15% efficient? Will the electric company pay you for extra power, or do they just get to keep it.  If the latter, they are probably going to have a say-so in the size.  Also, you are going to need many panels if you plan to use ac and size it to the peak demand.

I think we could skip the AC….the temperatures don’t seem to be as bad as where we are at (higher elevation and better breeze, I think is what does it). The designer was talking about putting in a heat pump, which I am told gives you both cooling and heating, although I’ve never used one. The util co keeps any excess electricity you generate so sizing the system properly is a major concern. As for using the AC or heat pump or whatever we end up with, my understanding is that the utility power will pickup any slack in our PV system.

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Will be a lot of slack with a heat pump, unless it is ground source and even then you could well be talking a very large solar system.  It would be simpler to go propane for heat and forget ac.

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Your designers idea of a heat pump is not going to work well with solar. My home has a 5 ton 12.0 seer unit. Running amps is 22, locked rotor or starting amps is 89. Arizona Public Service has a solar play ground 3 miles from my home they have heat pumps running on solar, but they have 15 horse gensets sitting next to them because of the starting current. Works flawlessly, ya got $500k for the system. Be realistic, IF you can convert most of your appliances to gas do so, especially cooking water heating and heating in general. You can run most of the rest of the home on 12-24 volts. The biggest problem you will face is the washing machine, heat pump freezer and refer. Washing machines can take out generators when they go into spin cycle.  A Arizona Public service sells a unit that looks like one of those shipping containers, with a propane powered generator all ready connected for charging. I don’t remember the price exactly, something like 10kw of solar for $25000.00. Your intentions are admirable. Do some more research, trying to run a home on dc is a night mare, let alone the increase in cost of the wiring. My opinion only Alan
Will the electric company pay you for extra power, or do they just get to keep it.  If the latter, they are probably going to have a say-so in the size.  Also, you are going to need many panels if you plan to use ac and size it to the peak demand. I think we could skip the AC….the temperatures don’t seem to be as bad as where we are at (higher elevation and better breeze, I think is what does it). The designer was talking about putting in a heat pump, which I am told gives you both cooling and heating, although I’ve never used one. The util co keeps any excess electricity you generate so sizing the system properly is a major concern. As for using the AC or heat pump or whatever we end up with, my understanding is that the utility power will pickup any slack in our PV system.acuum solar hot water heater

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