HowMuchIt / Video
How many solar panels do I need? The 10-second version
Ten seconds: your bills, your sun, your panels. Then work out your own roof with the calculator.
Open the calculator: How many solar panels do I need?
What the video shows
A homeowner stands in the yard with an electricity statement in hand and looks up at a bare roof. A moment later the panels are up, and the answer is on the phone. The order is the one the calculator follows: start from what you use in a year, then from how much sun your roof gets, then from the panel you would buy.
Do it for your house
Add up the kilowatt-hours on your last twelve bills. Get the yearly production of one kilowatt of panels for your address from the free PVWatts tool, and read the watts of one panel on its spec sheet. The calculator gives the system size, the number of panels and the roof area. Type a price per watt only if you want the cost: it stays in your browser.
Before you ask for quotes
- Have your twelve months of kWh ready.
- Note which parts of the roof get full sun; shade cuts what panels make.
- Roof work and wiring are jobs for licensed professionals, with permits.
On screen, word for word
- How many solar panels do I need?
- Your bills. Your sun. Your panels.
- howmuchit.com
- How much do I need?