Blind devotion can put you on the losing side
Fanaticism is typically associated with political extremism or sports. Seems like a pair of odd bedfellows. Although if you have met a die hard sports “fan”, you know it’s really not that far of a stretch. I for a time was a sports fan, but my team was sold and moved away. So I can understand….to a degree, how one can become emotionally irrational when it comes to supporting their favorite team. Or a point of view for that matter.
Such is the case I have found with whole house fans. A whole house fan is just like the name says, a big fan meant to cool the entire house. These big blowers are installed in the ceiling below the attic, exhausting the hot house air through the attic ventilation to the exterior. I find many people simply love their whole house fan. I know this because when I state that I’m not a fan, I get a very impassioned response from the owner of said fan.
As a home inspector I see several technically related problems with these devices. The first being, where does all that air go? The attic vents are almost always to small to exhaust all the air pushed by these large (about 3 feet in diameter) fans. Second, with use the vents become clogged with dust and dirt carried by the fan into the attic further restricting air flow. Which means the attic ventilation itself becomes restricted when the fan is off, which brings up yet another point. The fan is used very little during the course of a year. When not in use the opening is a large, un-insulated hole in the ceiling.
For some reason, I have found a good number of homeowners, both new and seasoned, seem to not recognize the detriment to having a large un-insulated area in their ceiling. This would include the attic access. Most realize quickly, when discussed, the heat loss associated with a lack of insulation over the fan or an access, but few fail to understand cooling loss. Attics get hot in the warmer months, the insulation also keeps the cool air in and the hot air out of the living spaces. So when the fan is not running, it’s contributing to the warming of the house, which it will be called on to “fix” later in the day.
I do find some of these fans covered with insulation, often haphazardly, on occasion, but most are left as is, diffusing the heat the homeowner is paying for, into the attic. I will usually half kiddingly state that the snow on the roof over the fan will be the first to melt. In fact I recently found direct evidence of the whole house fan actually creating a mini ice dam.
Climbing my ladder onto the roof I saw the tell tale water staining on the siding and soffit from an ice dam. The stain was very localized, being about three feet across. Examining the rest of the house exterior I saw or didn’t see staining any where else on the siding. Later, when inspecting the attic I found the attic insulation to be uninterrupted with the exception of where the whole house fan protruded into the attic. There was not a cover or loose insulation anywhere in the vicinity of the fan, meaning it was left exposed all year round. The staining on the exterior directly corresponded with the fans place through the ceiling.
In my mind this just demonstrates of why I’m not a fan of the fan.