Solar Heating Guide

William McDonough once described solar power: "it just so happens that there's an enormous fusion reactor safely banked a few million miles from us. It delivers more than we could ever use in just about 8 minutes. And it's wireless!" It is also free; we just pay to capture it and move it around.

What is Solar Heating

Evacuated Tube Collector: Power from the sun, which can be used to heat water, air, or be turned into electricity. The best thermal solar systems use an evacuated tube (like a thermos bottle) so they are unaffected by cold weather; inside the tube is a heat pipe, containing a liquid that evaporates, absorbing the heat from the sun as it changes states. This rises to the top where it condenses, releasing the heat and transferring it to water in the manifold. Gang as many of these as you need together and it can generate a great deal of hot water all year round.

Flat Plate collector: Simply a box with a glass top and a black interior; pipes running through the box pick up the heat. Alternatively, flat plate collectors can be used to directly warm air instead of water; a lot of home-made systems work this way. Here are plans for one you can build for under five bucks.

Why we like it

Did we say Free? Once the system is paid for, one gets a lifetime of carbon-free, green energy.

What we worry about

Night, when the sun doesn't shine. It has to be part of an overall system design that stores the heat, or used in combination with other forms of heating, or built into a Passive House system that is so well insulated and sealed that no additional heat is needed.

We also worry that people are putting expensive photovoltaic systems on their roofs because they are fashionable, whereas solar hot water systems delivering the same amount of energy cost a tenth as much. It makes absolutely no sense, but as one commenter noted on an earlier post about this subject, solar hot water isn't sexy.

Eco-factor of Solar Heating

The greenest form of all heating systems. Properly designed, it needs a small amount of electricity to run the pumps, (which can be run by a photovoltaic panel so the system can be entirely off grid).

Costs of Solar Heating

Evacuated tube systems used to be rare due to the very high cost; a system for a house could cost $ 20,000. Then the Chinese started manufacturing them in quantity and you can now get a system large enough for a house for $ 4,500. For cooler climates they are by far the most effective kind.

Flat plate collectors can cost as little as $ 450 to purchase; or, as we noted, five bucks to build yourself out of easily available junk.

Learn More:
When Solar Panel Installation Goes Wrong: 5 Things to Avoid When Solar Powering Your Home
Are You a Solar Power Wiz? (Quiz)