When you think of power you usually think of electricity. While the sun is an abundant source of light that can be converted to electricity, the bulk of the energy that comes from the sun is in the form of heat. A good solar panel can convert 15 to 20% of the light we receive into electricity but that's a small percentage of the usable power we can capture from the sun.
If you look at energy consumption in a home, most of it is used for heat. Space heating, cooking, and hot water are all examples. How hard is it to collect that heat and put it to work? The answer is that it's really pretty easy. Building a solar collector is well within the reach of the average do-it-yourselfer.

Let's take a look at how much energy we can capture. A 4x8 foot solar collector can capture about 5,000 watts of heat energy. This amounts to 17,000 BTU! That's a lot of heat. This is roughly equivalent to three 1500 watt electric space heaters people often use in the winter. With that much potential collectible heat available, even a less than NASA quality heater can be very useful.

More area exposed to direct sunlight equals more potential heat to collect. Flat black paint absorbs and converts the light into heat. Insulation improves the efficiency since heat is not so easily lost to the surrounding air. That's the basic theory. You need to be sure bushes, trees and other obstacles aren't in the way of the sun's view of your solar heater.

Improvised Solar Hot Water

All we need to do is focus the sun's light on an insulated container which contains a water tight tank of water. If the tank is black, the sunlight can pass through a glass window and heat the tank and the water inside it. Voila! Hot water. This idea is nothing new and is something that most of us can build. I originally read about a fellow who built a water heater like this many years ago in Popular Mechanics. He built it for his shop and it gave him plenty of hot water for his bathroom. There's nothing patentable of magic about this kind of heater and it works well.

To build your hot water heater you need a water tank. One easy way to come up with a suitable water tank is buy a used electric hot water heater, and use the tank inside. You want to be sure that it is in good condition and you will want to remove the heating element and buy a plug.  Your local hardware store can provide the plumbing supplies.

The tank lays horizontally in a wood frame, so you will need to route pipe for the water inlet and outlet. You need to have a vent in case your water boils. You don't want to build pressure in the heater, just hot water.  Be sure all your fittings are water tight. The tank is surrounded by a roughly U shaped insulated plywood box. The top of the U is at 45 degrees with a glass window allowing sunlight direct access to the tank. The tank is painted flat black to increase energy absorption.
In its simplest form you could just pipe water up into the tank to fill it in the morning, with gravity feed down to your sink. If you use a 40 gallon tank you'll have quite a bit of water to use through out the day. If there's any danger of freezing, just drain what's left in the tank in the evening.  Be sure to remember that water is heavy, and 40 gallons weighs over 200 pounds, plus the weight of your heater. Be sure you safely secure it so it stays safely in place on a solid mounting spot.

Homemade Solar Space Heater

Another easy way to put solar heat to work, is to build in a solar space heater. To do this you need to be a skilled carpenter so that when your done the result is pleasing to the eye. Once again I'm not going to provide exact plans but provide you with ideas that are proven that you can put to work in your own way.

The way this is done, is to remove a section of the exterior siding on a south facing wall of your home where there are no windows. The space between vertical studs that support the wall are painted black, any cross bracing is removed, and the exterior siding you removed is replaced with thermal insulating glass. On the inside of the wall vents at the top and bottom of the wall are opened when heat is required. The sun heated air rises in the wall and exits the top vent. This system can provide a lot of heat and reduce your heating bill in the winter. Every watt of heat you collect is one less you have to pay for!

Design Your Own

The principles of solar heating are actually quite simple. Reading about how others have solved some of the construction problems can help your project go more smoothly. If you design your own system, you can take advantage of your unique living situation. You don't have to spend big bucks if you don't want to, even though many do and are very happy with the results. I like to 'do my own thing' and I find solar projects to be a lot of fun. Perhaps you will too.

A little skill, a little thought, and a little effort can enable you to harness the sun, save money, and give you neighborhood bragging rights.

Go solar.

DIY Solar Projects: How to Put the Sun to Work in Your Home
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DIY Solar Hot Water, Solar power From £50
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