Buyer's Guide to Solar Heating

Tap free heat from the sun with these solar hot-air collectors.


| December 2006/January 2007



solar hot air system - Solar Max

SolarMax collectors incorporate 240 aluminum cans.


Cansolair

Are you freezing in the winter to keep your fuel bill down? Or paying an arm and a leg to stay warm? Either way, it’s probably time to consider installing a solar hot-air system. There are several options, and these systems are a hot commodity right now — in recent months several suppliers have reported increased consumer interest.
Solar hot-air systems capture sunlight energy and use it to heat incoming air. Heated air is then transferred into your home, often with a small electric fan. The solar energy costs what it always has cost — nothing. Solar hot-air systems can help alleviate homeowners’ worries about rising fuel costs and provide years of inexpensive, maintenance-free comfort. They can heat homes, offices, workshops, garages and barns.

Solar Simplicity

All solar hot-air systems rely on hot-air panels or collectors. Collectors are typically mounted on south-facing walls, roofs or even on the ground, if it’s unshaded during the heating season.

Some commercial systems are simple thermosiphon collectors that rely entirely on convection to distribute hot air, but most use fans or blowers controlled by relatively simple electronics. A temperature sensor mounted inside the collector monitors internal temperature. When it reaches 110 degrees, it sends a signal to a thermostat mounted inside the home, which turns on the fan if room temperature is below the desired level. When the temperature inside the collector drops to 90 degrees, or the room reaches its setting, the thermostat turns the fan off.

Solar hot-air systems actively produce heat only in the daytime, but some of that heat is absorbed by the building’s thermal mass: drywall, tile, framing lumber, etc. At night, the heat stored in the thermal mass radiates into the rooms. The more thermal mass, the greater the nighttime benefit.

Hot Air vs. Hot Water

Solar hot-air systems are far simpler and easier to install than solar heating systems that circulate water as the heat-transfer medium. They’re also less expensive, and don’t use potentially troublesome chemicals or require complicated electronic controls. You can even build a solar hot-air system yourself (see “Build a Simple Solar Heater”).

Solar hot-air systems also produce heat earlier and later in the day than water-based systems. As a result, they may produce more usable energy over a heating season than water-based systems of the same size, according to the U.S. Department of Energy’s online publication, Consumer Guide to Energy Efficiency and Renewable Energy . Moreover, air systems do not freeze. Minor leaks in the collector or distribution ducts, which cause significant problems in water-based systems, also are less troublesome in hot-air systems. (Water-based heating systems do have one major advantage: They can store heat for use at night in water tanks inside the home.)

gina_21
9/30/2009 7:30:11 PM

I realize that this article is a few years old, so I would like to add some information about an amazing socially progressive organization that manufactures solar air heating panels. The organization is a non-profit called the Rural Renewable Energy Alliance (RREAL) based in Pine River, Minnesota. They manufacture the SPF Solar Powered Furnace solar air heat systems. They also design and install photovoltaic and solar hot water systems. The organization is headed by Jason Edens and BJ Allen. Their mission is to make solar power accessible to people of all income levels. They do this by offering the Solar Assistance program where solar air heat systems are installed on the homes of low income families who qualify for energy assistance for no charge to the families. The Solar Assistance program is supported by grants, donations, fund raising, and the profits from market-rate installs. I am a student in the Sustainable Living program at Maharishi University of Management and interned with RREAL for a month in May 2009. I was completely blown away by the dedication, generosity, and perseverance demonstrated by the people in this organization. I would love to see them get more support for what they are doing, promoting social justice, renewable energy, and reducing dependence on fossil fuels. If you do an update on this topic, please include them in your sources for solar air heating. More information can be found at rreal.org . They deserve your support. Thanks. Gina


sh
9/27/2009 9:41:16 PM

Does anyone remember an article in Mother Earth News or Popular Science about solar air collectors, tube format that basically hung in your home toward windows that faced the sun, if I remember correctly, the black tubes were about 6 feet in lenght and would draw air up and out as being heated by the sun coming thru the windows. There was no power at all used. Its was a long time ago and I dont remember all the details? Do any one remember the rest of the story or have details? Thanks S


doug_8
1/8/2009 5:58:33 PM

We have a 2100 sq ft home in Ohio. The house has no duct work it is currently being heated by electric baseboard heaters. Would this type of heating be recommended for a house like ours. We are wanting to heat our home with some sort of renewable energy but feel completely lost at the moment.


dan_26
11/25/2008 6:56:13 AM

This article to me is the unofficial source on what solar air heating is all about. It is very well written and I refer to it often. It is in part because of this article that we purchased and installed a solar air collector on our home's south wall this fall. We are writing a series of article on our family's home blog about our our adventures for those who want to read more about solar air collectors detailed installation, parts, performance, etc. If interested you can access the series of our home blog's solar air heating articles here: http://dailyhomerenotips.com/2008/11/10/solar-air-heating-part-6-unpacking-the-solar-max-240/ However, this article states that the SolarSheat was able to constantly provide a temperature rise of 40 degrees. Well we purchased the Solar Max 240 from Cansolair for various reasons. What surprised me was the temperature rise we are experiencing. Using just an Infra-red temperature reading device, we measured a temperature rise of 60+ degrees in the ceiling vent 24 feet away from the Cansolair product, from a temperature around 72 degrees F at 7 am before the sun came up to between 135 to 140 degrees F about an hour after the unit was on. Various manufacturers are out there and as shown in Mother Earth News there are various DIY construction plans for those with the apptitude, patience and time for these wonderful environmentally friendly supplemental heating sources. Dan






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