Solar Power & Energy

Overview
Solar furnaces aren’t quite as robust and large as conventional home furnace systems are. Solar heaters are usually space heating designs, which heat a room or space in a home instead of the entire house at once.

Conventional Furnace
To use a conventional whole house furnace with solar power, you’d need to buy a solar panel power generating kit and connect it to an electric furnace. Then you’d be using solar power to run the furnace instead of using standard household electricity.

Running a whole house electric furnace on solar power could be expensive however, depending upon how large your furnace is and how much power it needs. Home furnaces tend to use a lot of electricity, and the more your furnace needs to be on the more solar power you’ll need to be able to collect for it.

Determining how much electricity your furnace needs is a simple math equation: The number of amps times the number of volts equals the amount of watts your solar panels need to generate.

So a 110 volt furnace which uses 5 amps would need solar panels which generate a minimum of 550 watts for full time use. If you’re only using your furnace part time, you can store some of the power generated by the solar panels. The solar power is usually stored in batteries, then your furnace can pull off of that stored power as needed–even at night time.

Solar Space Heaters
The more common type of solar furnace is a space heater design. Small solar heaters like this can be attached to a window which faces south, a wall which faces south, or they can hang below a south facing window via the window sill.

Solar heaters like this take cool air from inside a room, warm it up from sunlight, and release the warm air back into the room it was taken from. This creates a circulation effect that continuously warms the air in your house.

Putting several of these small solar space heaters strategically along the south facing side of your home could generate enough warmth to replace a conventional whole house furnace.

Small solar furnaces of this type are easy to make yourself. They are just a box frame with a black metal back and glass on the front. The metal backing has vent space at the bottom and top: The bottom vent is the cold air intake and the top vent is the hot air outlet.

You can make the heater sized to fit your available wall or window space, and it’s estimated that a 4ft by 4ft heater frame will warm up about 400 square feet of space. Three to four solar heaters built well could effectively replace a furnace for a house ranging from 1200 to 1600 square feet in size.

References:
1. Planet Green

2. How Much Electric Is Needed