Joseph asks…

Can Solar Panels Power My Whole House-Including A/Cs?

Hello, I’d really appreciate some input on the subject of solar power panels. I’ve ready a lot and I’ve learned a lot in the recent months by Googl’ing and I realize it’s a big undertaking and in order to generate a small amount of KWH it takes a lot of hardware/installation. I’ve been very interested for some time in this subject, not so much for my needs here in California (where my average monthly electrical bill is roughly $65, even when I run the A/C in my studio from time to time), but more for the time I spend in Rio de Janeiro, Brazil, where electricity is about 10 times as expensive and where the price per KWH increases every 2 months.

My question is; how realistic would it be to attempt to power a house in Brazil using solar panels? Of course it would be preferable to completely power the house with solar power, though partial solar power would also be helpful. It is hot in Rio 9 months out of the year (sometimes even all year long), and when it’s hot there is plenty of sun. The cost of electricity is so high in Brazil (roughly 6 times higher than the US…and it goes up every 2 months or so) making it unaffordable to run A/Cs for most people.

1. Is there any way that I could run between 3-5 wall A/C units in a house, or one central A/C unit for the whole house (all day and all night) as well as to run the rest of the house‘s appliances (fridge, freezer, TVs, computers, lights, etc) using solar panels? I realize I’m asking a lot and I’m not sure how many KWHs it would require to run all of the above-mentioned, but is there a chance it could be done by only using the roof of the house as the resting area for the panels? If so, how much would it cost in hardware/installation to generate that much electricity?

2. I’ve seen solar panel systems on TV shows that apparently generate DC and then it gets converted to AC and then something else happens so that it can be used directly for the house…and when there is an excess of electricity, it feeds that solar-generated electricity back into the city electricity which turns back your meter. I have also seen systems that have battery arrays that are charged from the solar panels and then the house is run off of the batteries. Which of these 2 methods is best? (In my case, there may be one month where we’re not at the house and one month where we are…could the “off months” be used to store generated electricity?)

3. Does anybody know if it would be better to seek to purchase solar panels in Brazil, or cheaper to import them from another country?

4. Has anyone heard of the SolCool Solar-Powered A/C? http://www.inhabitat.com/2007/07/16/solcools-solar-air-conditioners/ could this be a solution for those of us seeking to power A/Cs from solar panels?

Thank you for taking your time to read this. Looking forward to your answers!
Thank you to all for your good answers and input. Is there any way that I can add answers (to your answers) or further comments to this thread?

Henry Dover answers:

Woah…way to much info for a question…so I’m going to write my answer based on JUST the question and not the book of additional information you posted.
My understanding is no, solar power isn’t there yet. However, you could greatly reduce your energy costs by supplementing your home with solar power. How much really depends on where you live. For example, in the arctic Minnesota area where I am from, solar would not be the greatest thing. We get a lot of snow fall in the winter (thus covering the solar panels till they could be cleaned off) and we have some very short days in the winter with a lot of overcast days (thus reducing or eliminating the effectiveness).

I think it would still be a worthwhile investment if you plan to live in the home long enough to allow the solar panels to pay for themselves.

Ruth asks…

Can two solar panels power a whole house?

three bedrooms
two bathrooms
air conditioning/ heater
electric kitchen appliances
flat screen TV with surround sound speakers
Flat screen computers in each room

Henry Dover answers:

Hi Alina, unfortunately , the answer is NO. I live off the grid and have for over 16 years now. First of all , you cannot run your air conditioner off solar unless you have about 48 panels and 25 very large batteries. The elect. Range is way out of bounds for solar as well as any elec. Heater. You could however lessen you bill by at least a third or More by switching your main use appliance over to gas. IE> tankless water heater, gas stove, gas heaters and things like that. If you want to learn more, contact me through email, and I would be happy to educate you on solar living. There are also systems called sell back where you have the solar panels, and during the day while they are making elect. You sell it to the power co, and at night you buy from them. Usually cuts your bill by about 90% or more, depending upon your being careful , especially at night.

Betty asks…

Is there a way to install solar panels for one appliance in my home rather than the whole house?

After getting estimates from several local contractors, I can‘t justify the cost of taking the entire house solar – especially since we’re considering moving in a few years and solar power would price the house out of the market for its size.

In the meantime, though, is there a way to route solar power to one high-use appliance – say our PC or our TV – without fully rewiring the house? This would incur some savings and a lower cost, and we might be able to see some return on investment when we sell the house.

Henry Dover answers:

Not very practical if you ask me. The way the solar system works in a nutshell. Panels turn sunlight into DC electricity, think the battery in your car. Then an inverter is installed, which turns the DC into AC, which is what is used in your house. The system feeds your needs when the sun is out, and any excess produced during the day turns your meter backward, and at night you draw from your power company. To do for a single outlet, it would work during the day, but at night or if it got cloudy you would have to move the power cord,to the other outlet hooked to your regular power. If you put solar on your house it might make a great selling point, when you show the new potential owners your electricity bills, depending where you live, it could be close to ZERO for the year.

Chris asks…

Can I have a 100% fully solar power home without making any compromises on energy usage?

If I build a house or convert an existing house, even if i have to fill the whole roof with solar panels, is this possible? I mean, heating, hot water, TV, appliances, Washer, Dryer, PC and all the electricity I need, even floor heating, absolutely zero compromises and zero usage of any other source but solar panels, even if I want to put floor heating in the whole house, is this possibly or is it just me dreaming?

Henry Dover answers:

In theory, yes – on a clear day we get around 1000W per square metre in the UK so a large enough array of solar panels for both electricity and heat, plus a massive storage battery system, could run a house.

In practise, the cost would be astronomical as you have to guarantee sufficient storage capacity to run the house for days at a time during bad weather, and have enough generation capacity to recharge the system quickly as well as running everything.

Most energy efficient buildings use mains electricity and use the grid as the ‘storage’ system; you are paid for power you produce when there is excess, which offsets the cost of electricity when your (small) storage system is depleted.

Re. The underfloor heating: The best system is an integrated air conditioning/heating system using a reversible heat pump setup with an underground ‘heatsink’. You dump excess heat several metres underground from the air conditioning, then pull it back for heating.

You get roughly 3KW of heat transfer for 1KW of power to the heat pump.

Paul asks…

Would it be safe to turn on power in a home after 13 years?

My grandma died 1998. She lived in a very nice house that we ended up with it. We still pay for electric :P but without heat for 13 years. I went in the house to check on it today I haven been in it scents 2005 but other people checked on it for us. The house is still looking clean but has a few cracks in the fresh painted walls. We wanted to put the home on the market. The main power box is off, But it also has solar panels on the roof that still work well and back in its day can power the whole house. Solar panels still making power and charging the unit like batteries. The electric company still takes the left over power and we get money. But the main panel of the home has been off for 13 years. will it be unsafe to turn the breaker on to power the home? I’m just trying to be safe.
Just an update, Today I went over do as I was told, I turned off the power to the solar panel’s, Slowly turned on the box, Funny how the music just started playing in the withing room cracked me up LOL! but everything works exp for the water pumps.

Henry Dover answers:

I would not pay someone to inspect it. If the power has been on since you stated. I personally would seal the house “as is” and be very clear about that. Something to the effect of family mother passed away 13 years ago, and you just took legal position of it. Or however you got it. Trust me, there will be major stuff wrong with the house. Possible plumbing as the house was never winterized, water heater, heating and air system possibly. Something that sat that long may also have mold issues seeing that the AC was not on as well. Thats how I would approach it. Otherwise if you pay an inspector your going to probably find out that guessing here an easy 5-8K worth of work would need to be done to it. I would just adjust the price accordingly off the selling price.
I bought a home like that that set for 8 years, and to be honest it was nothing but a nightmare. But I knew it going into the deal. And the price was so cheap that even after dumping 15K I still was way below what I would have had in it if it was turn key IE move in.

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