It’s a common question. “How many solar panels do I need to power my ### square foot house?”
The answer is not so simple. In fact, I can’t even give you a rule of thumb. Some industries can tell people a reasonable range for sizing equipment, and often building codes dictate sizing of appliances. For example, an A/C company might tell you that on average you need one ton of air conditioning for every 600 square feet of living area for a Southwest Florida home. A plumber might tell you that you need a minimum 50 gallon water heater for a 3 bedroom, 2 bath home. There is no such approximation with solar energy.
The energy used by a home, and more specifically a homeowner, can vary tremendously (note: homes don’t use energy – people do). My 3,000 square foot home uses about 2,000 kilowatt-hours (kWh) of electricity each month. I’ve been at a customer’s 2,500 square foot home that uses 3,500 kWh of energy! That would be a range of 0.67 – 1.4 kWh per square foot per month – hardly a useful range to use as a rule of thumb.
Energy use is complicated. People have very different habits, standards of living, and luxuries.
I was at a customer’s home where they had two refrigerators in the garage. That is the worst place to put a refrigerator in Florida (because of the ambient temperature). But two?! They were wondering why their electric bill was so high despite the installation of solar products. I think I have an idea…
Pool homes consume more energy generally. Old air conditioners and poor insulation cause poor efficiency for cooling. Some people run incandescent lights in their yard 12 hours a day. And many times, habits are the cause.
Even the utility company averages have little value. LCEC and FPL report about 1,100 kWh per residential account. However, that includes small condos, separately metered buildings, manufactured homes, and seasonal residents. It’s not a good metric to use – just about every customer we visit consumes more than the “average.”
What we need to know is how much energy you use. Fortunately, that’s easy to find out. Both utilities in Southwest Florida have online account history that shows you energy use by month. Fafco Solar’s solar advisers can help you figure out how much energy you are using and how many solar panels you need to power your house!