CALCULATING SOLAR

[Karen Margrave]

I own a 4400 sq. ft. house which has a 2100 sq. ft. guest house in Redding, CA. With the rising cost of electricity, I am considering solar. Also, because both buildings are on one meter, it kicks it up to Tier 4, the priciest, very fast. 

The house is on PG&E. My dilemma is that PG&E won't tell me how many kwh the house averages for me to be able to do any type of calculations, because the power is in the tenants names. They won't even give me a rough estimate based on the size of house, etc. as to what it should be, etc. 

Does anyone know of a formula based on the square footage of a house to try to figure out what would be required in the way of solar panels to generate 100% of the electric from the solar?

I have 20 acres, and Redding is one of the sunniest cities in America, therefore; plenty of sun. I could do banks of panels on the ground, or on the roofs (which are south facing) Also, the house is very well insulated, has attic fans, etc., as are the garages and the guest house.

I know new nano technology coming on soon, but who knows when?

Has anyone ever achieved 100% from solar?

Does anyone else have a large house they use solar on? 

Costs? 

[Kevin Martin]

@Karen Margrave

Everything starts with the power usage especially if you are trying to go net zero and make all your own power. There is a great online tool (pv watts) and it will give you a very close estimate on how your system will perform after its sized. There are many factors that go into sizing a system but it usually starts with past usage, goals, application, budget, etc.

We built a 1,600 sqft home a year ago with a 5kw system and a solar hot water heater and the owners had an $18 electric bill in July. We got the house tested and it came out to a HERS score of 9; maybe another kw or 2 would of put them over the edge for a net zero house but it really depends on usage. Also, keep in mind this was new construction with some other energy efficient building materials/practices.

Based on your info I would say maybe a 7-10kw system should get you close to making 90-100% of your own power but like I said above there is alot that goes into this. Either way, the cost of electricity in California is way high and its more than worth it no matter how much power you make.