If I add 4 large 12V computer fans to my roof vent and power them by a solar panel, will it make a difference?

Question

i would like to construct 4x 12VDC computer fans under my roof vent. These would be wired in parallel to a 12V solar panel (Wattage depending on size of fans). I know this would only work during the day, but that's really all I need. My question is, would this make a difference in the temp in the attic or am I wasting my time. Really, I don't want to spend $300 of a pre-made kit and have to replace the vent.

Answer 1

I'm a roofer, any fan unit will help to exaust the heat from your attic, but make sure you have the proper vents to begin with; sofit, ridge, and you obviously have gables. They all work together.

Answer 2

Will it make a difference in what?

You should have insulation between the living space and the attic.  The attic should be properly vented.

If you want to cool your attic down, my guess is that due to the volume of the attic the CFM of the fans will be too low to replace the air faster than it will heat up.

There is also the issue of static pressure and your fans effectiveness.

Answer 3

Totally cool idea, and yes it will make a diff

Answer 4

you will definitely be wasting your time

proper venting is through natural convection flow -- cool in at the eve vents and hot out at the ridge.



venting starts with screened openings in the bird blocks between rafters and either mushroom roof vents or continuous ridge vents at the top.

improperly installed ceiling insulation is the most common problem with attic venting -- make sure there is a clear path for air to flow over the insulation right behind the bird blocks --

cardboard baffles are often stapled between to the rafters to keep the passage clear

Answer 5

We had a solar vent put in our roof, and were amazed at how much cooler the house got.  Years later, the house was still cool, but when I went up to check the fan, I found that the solar panel had burned out, and the fan was not moving.  Apparently, just having a large vent near the ridgeline, even without forced air, is enough to make a huge difference.

If I had to do it again, I would put one of those wind-powered vents, the kind that looks like a turban, up there.  In our neighborhood, those things have been on people's rooftops for like 20 years.  They've rusted, but I still see them turning in the breeze.

If you really want to use the existing vent, maybe consider one of those really powerful attic fans, that plugs into AC.  You would only need to run it on low, or maybe just for a few minutes to clear out the hot air.

Answer 6

All attics are hot in summer and cold in winter. So why are you worried about it?

But if you are, First make sure the vents at the eves of the attic are clear. that way you have movement of air.

Second, if your still concerned you can put vents in the side walls of your attic.

Third and most important- make sure you have lots, and I mean 10" to 14" of insulation in the cealing of the room below the attic.(the attic floor) This will help keep you cool in summer and warm in winter.

Unless there is a specific problem with the construction of your house and roof I would recomend the K.I.S.S. plan. (keep it simple _____)

The attic will ventalate itself, if you keep the vents clear.