Solar panels have enjoyed a meteoric rise in popularity in recent decades. That’s thanks in part to an increase in environmentally responsible behavior and the desire to reduce energy bills by exchanging traditional sources of heating, cooling and electricity with cleaner, more natural sources. If you’re thinking of making this switch, you’re probably wondering how many solar panels it takes to power a house.

While the answer can be a bit complicated, if you hire a professional or off grid solar system installation company to consult with, they’ll likely handle this part of the process as well (and may give you tips on how to maintain and clean solar panels).

But if you’re wondering how many solar panels you may need, and you’d like to take a stab at calculating it yourself, you’ll need a few pieces of information: how much energy your household uses; how much space you have on your roof that can be used for solar panel placement, how many hours of sun your home gets and the wattage and relative efficiency of the photovoltaic (PV) solar panels you’ll be installing.

Factors that Affect How Many Solar Panels You Will Need

Is there anything else to think about outside of the above calculations? Turns out, there are a few other things factors need to consider when determining how many solar panels to power a house.

System Efficiency

Your solar panels won’t draw the sun’s energy at top capacity all the time. Think of those three-day bouts of rain that come in the fall, or large snowfalls in the winter that take several days to melt. Those are times you’ll need a buffer in your energy usage, so it’s recommended to have about 25% more solar panels than you need.

Hours of Sunlight

The amount of energy you’ll get from your solar panels is directly related to how much sun your home gets. More panels will be required if you live in an area without long hours of strong sunshine.

Wattage of Your Panels

Most solar panels range in wattage from 150 to 350 watts per panel. If you choose lower wattage panels, you’ll need more in order to generate enough energy for your home. Of course, that’s assuming you’d like to replace 100% of your energy usage with solar energy. If you’re only hoping for a partial conversion, the difference in solar panel wattage may not matter as much.

Cost

How much do you want to or plan to spend on your solar panels? Before you buy, make sure you know how many make sense for your budget.