Four Pros And Two Cons Of Solar Attic Fans

by Nicola Temple on February 27, 2012

Anyone who has had to crawl up into their attic on a hot summer day appreciates the value of a ventilated attic. Fans can help exhaust that hot air from your attic, and a solar attic fan can do it using clean energy from the sun.

When the sun’s rays hit your roof tiles, they heat up…a lot. Some of that heat is transferred from the surface of your roof into the attic space itself. Depending on how well your attic space is insulated, there could be a great deal of heat being transferred into your home.

In summer, this means that your air conditioner has to work that much harder, which can be a real energy drain, not to mention financial drain. If you get that hot air out of there, your air conditioning won’t kick in as often and you could be saving some money.

This cost savings can be diminished when you use an electric fan because some of the energy you’re saving on driving the air conditioner is now driving the fan; but solar energy costs you nothing.

If you’re still undecided about going solar, here are some quick pros and cons…

Four pros of a solar attic fan…

1. Solar units are self-contained in that they don’t require any wiring. You just literally pop the unit in a hole in your roof and you’re ready to go. This is particularly useful in attic spaces that are very difficult to access.

2. Since there is no wiring involved, solar units are much easier to install than wired in units. In fact, here’s a video to show you just how easy it is:

3. Solar energy is a clean, renewable resource that doesn’t cost you a penny. For most solar attic fan models, the solar panels come with a 20 or 25 year warranty.

4. Solar models are generally considered much quieter than wired versions.

…and two cons

1. There have been claims that solar-powered fans can be under-powered.

2. The fans don’t run at night. This is a drawback as air will stay hot in an attic space even once it’s dark and temperatures outside have started to cool. Without a battery, this isn’t going to change.

A solar attic fan that seems to meet expectations:

solar attic fan

The Natural Light solar attic fan has an adjustable solar panel, which helps maximize its efficiency.

I’ve spent quite a bit of time scanning feedback from people who have bought solar attic fans, and products manufactured by Natural Light seem to come out on top.

They make models that are 10 watts, 20 watts and 30 watts, each with a 25-year warranty for the entire unit, suggesting the company is truly confident in its product.

The fans range in price from $310 to $467 USD.

The flashing that comes with the unit is made from one piece of heavy gauge stamped aluminum and has no seams, ensuring it’s leak-proof.

Another nice feature is that the high quality solar panel is adjustable so it can be angled for maximum sun exposure. The thermostat is sold separately.

Some considerations when purchasing a solar attic fan:

Some fans don’t have an adjustable solar panel, which is fine so long as your roof is positioned at an angle and aspect to maximize sun exposure.

Like many things, it would seem that you get what you pay for. Feedback from buyers of cheaper models seems to consistently be that the fan is underpowered or that after one year of use the unit’s motor died.

Also, before you head to the shops, you should calculate how big your attic space is in cubic feet. All attic fans are sized in terms of their cubic feet/minute (CFM) output. An attic fan should provide 10 attic air volume changes per hour, so you’ll have to do some minor calculations to figure out the size of fan you’ll need. Larger attics may even need two fans.

So, if you’ve been up in your attic lately and noticed that it’s a sauna, a solar attic fan might just do the trick. It’s relatively little investment of time or money on your part to help that air conditioning unit stay off more during the summer. Of course, making sure your attic is well insulated is the first step. That way, you’re also saving on heating costs in winter, which an attic fan can’t help you with! However, if you’ve done that and are still looking for ways to reduce cooling costs, this might be just the thing you need.

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