Tuesday, June 11, 2013

Our biggest fan

It's this one:


This baby can churn out somewhere between 6,000 and 7,000 cubic feet of air per minute (CFM). We sometimes use it in the evening or early morning to help cool down our non-centrally-air-conditioned house by setting it up in a window, blowing outward. Then we open up a bunch of windows to let in cooler outdoor air, replacing what the fan blows out.

However, this makeshift system isn't all that efficient. While the big fan can push out a huge volume of air, we don't really have a window to put it in where it can create a draft through the whole house. The big fan also uses a fair amount of power—between 100 and 180 watts on high speed, spiking up to 270 when it's first turned on. And it's loud enough to make conversation difficult, if not impossible.

So lately we've been toying with the idea of having a whole-house fan installed. If we put it right smack in the middle of the hallway, it would pull air through every part of the house. And during the past couple of weeks, when temperatures occasionally spiked over 90 during the daytime and then dropped into the 60s at night, we had a vivid demonstration of how useful it would be to be able to replace all the hot air in our house with outdoor air as soon as we get up in the morning.

Never having installed one of these things before, we didn't have a good idea how much it would cost. A site called Homewyse gave me a rough estimate of between $450 and $650, including labor; this article on HouseLogic was less optimistic, saying we could expect to pay between $150 and $550 for the equipment and $1,000 or so for installation. So, to get a more concrete idea of how much this would cost and whether it was likely to be worth the money, we decided last week to get quotes for the job from several local electricians.

Well, that was the idea, at least. In reality, two of the four electricians I contacted never got back to me at all; a third one e-mailed me with a couple of questions about our setup, and then never replied to my reply. The fourth one, by contrast, responded very promptly, calling me within minutes after my initial e-mail to set up an appointment. However, they couldn't commit to a specific time, saying only that someone would be there "in the early afternoon"—and then sending a follow-up e-mail to say "you are scheduled for Friday morning," leaving the matter even more ambiguous. So I spent most of Friday trapped in the house, unable to go out to the opening day of our local farmer's market, because I had no idea when to expect a visit.

The electrician finally showed up around 3pm, and the first thing he did was try to convince me that we need to upgrade our old panel box (which may be true) because "it really should be done every seven years" (which definitely isn't). Then, after spending the next 45 minutes checking this and that and trekking back and forth to his van, he finally presented me with a quote of around $2,275. Yep, more than $700 above the highest estimate we'd seen anywhere else. And this, mind you, was for a fan with a maximum output of 1,000 CFM; most sources recommend at least 1,500 CFM for a house the size of ours. And on top of that, the electrician told us we'd need not one, but two circuits dedicated entirely to the fan; he actually complained at first about the fact that we only had two free circuits with nothing on them, saying that a fan large enough for our house might need four. Four?! We know that a single circuit in our house can run our refrigerator (with the compressor on) and our microwave at the same time; that's at least 1,500 watts. Is the fan he proposes to install really going to draw four times as much power as that? If so, how can it possibly be more efficient than air conditioning?

So it might have seemed like that was the end of that idea. However, while researching whole-house fans in general, I'd happened upon the website of a company that makes what it describes as "Quiet Cool House Fans." According to their FAQ, these have two main advantages over a conventional whole-house fan. First, they're easier to install. They're narrow enough to fit between floor joists, so you just cut through the ceiling between to insert the grill, and the fan itself hangs suspended from the attic rafters. All you need is a standard 120-volt outlet in the attic to plug it in. And second, they're quieter. Because the fan assembly hangs from the rafters instead of being mounted right in the ceiling, it can push through the same amount of air without creating as much noise in the living space below.

These fans aren't cheap. The 2,250-CFM fan, which is the minimum size they recommend for a house the size of ours, costs $650 and uses 249 watts; the more efficient Energy Saver version, with an output of 2,850 CFM, costs $969 and uses 178 watts. But that's still less than half the price we were quoted to have a less powerful, less efficient, and louder fan installed. Of course, we also need to factor in the cost of getting an outlet added in the attic. Kudzu estimates the cost of that job at about $100; Homewyse puts it between $150 and $220. And if our town requires a permit (and it usually does), that could add another $50 or so.

So the questions now are:
  1. How much of this job can we actually do ourselves; and
  2. Is this fan going to be so much quieter and/or more effective than our current jury-rigged system as to make it worth between $850 and $1,170 to install?
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