Northern Arizona Wind & Sun

Electricity from the sun since 1979

How Much Will it Cost?

Every day we get asked something like "We have a 3200 square foot house. How much would a solar system cost?"

Well, the short answer is - how much money do you have?

The size of your house means absolutely nothing.

What does count is:

• Where you are in the world.
• How much sun you get per day.
• How much you use
• How much (if any) rebates and tax incentives you will get.

Where you are affects how much yearly average sun you get. Solar panels make power from the sun, so no sun, no power. In the US that can vary from a yearly average of about 4 to 6 hours per day. You will usually get more in summer, less in winter.

How much sun you get also depends on where the panels are, how much - if any - shade they might get during the day, and what angle and direction you can mount them at. To work best, solar panels should be aimed South, and tilted at around 15 to 40 degrees (again, depending on where you are).

See the PV WATTS program to figure it out for you. This is an online calculator at NREL and gives you a pretty good estimate.

How much you use each month is the main variable. To find out, look at your electric bill. Someplace on there it tells you how many kilowatt hours you used for the month, and often gives a daily average. It will also tell you how much you are paying. To get the TRUE cost, divide your bill amount by how many KWH you used.

How to figure the cost for 100% solar power

• First, take number of KWH shown on your bill. Divide that by 30. That gives you your average daily usage. So if you use 700 KWH, that is 23.3 KWH per day.
• Take that number. Divide it by the number of full sun hours you get per day on a yearly average. Multiply it by 1.15. That will give you a pretty close estimate of how many watts of solar panel you need. So if you get 5 hours per day, divide 23.3 by 5 - that gives you 4.66 KW, or 4,666 watts. Multiply that by 1.15, which gives you 5,360 watts of solar panel needed.
• Average installed cost of solar electric if you do it yourself is around $7 per watt, or $9 if you have it installed by a licensed contractor. That includes the cost of the panels, inverters, wire, mounts, and other hardware. It does NOT include anything else you might need to pay for, like inspections or extra watt meters by the electric company. So that system will cost you around $37,500. A battery based system will cost around 20-30% more.

See http://www.dsireusa.org for a list of Federal, state, and local rebates and tax incentives for your area. In some cases that can reduce your cost up to 50%.