Friday, August 21, 2009

A better bathroom fan

This year the house is getting a total makeover. At the beginning of this year my husband wanted to buy a bigger house to accommodate space for his hobby, which requires a large space for motion capture video. After he looked around some he came to realize, which I already knew, that our existing house is hard to beat for livability. It's in a quiet but convenient location and laid out very efficiently to maximize use of its 1000 sq. ft.

He figured out that he could make our garage work for his purposes, so no need for new house. However, we're moving everything out of the house to replace the wall-to-wall carpet with cork flooring. When we move back in, we're going to reclaim our master bedroom as a bedroom and use our den as our office.

The master bath had a 2.5-sone, 50-cfm (cubic feet per minute) ventilation fan that I had installed in 2003 to replace a very noisy fan that was there before. While quieter, this fan was not nearly as quiet or efficient as the very best fans on the market today. I decided that the master bedroom would become more livable if I put in a really quiet fan that ventilated better.

After a bunch of research I found a great fan by Panasonic sold by R.E. Williams Contractor. It's 80 cfm, and only 0.5 sones. It's designed to run all the time at a lower air flow (at 0, 30, 50, 60, 70, or 80 cfm), then kick on at a higher air flow when someone enters for a set period of time. I set mine to be zero cfm when unoccupied and to run for 20 minutes at 80 cfm when occupied.

That it kicks in automatically means that there are no issues with odors leaking into the bedroom when the occupant of the bathroom forgets to turn on the fan.

At first I wired it so that you couldn't turn the fan off, but my husband complained that he wants the fan off while he showers so that he doesn't get cold. So I put it on a switch so that he could turn the fan off when he's going to shower and then turn it back on when he's leaving the bathroom. The fan automatically shuts off after running for a set period of time that you set with a dial inside the fan.

It took me all day to install the darn thing. The mounting instructions were complicated to figure out. But after I read through the many different mounting options at least a dozen times while puzzling over the different possible pieces of mounting hardware, I finally figured out the method that worked best for my situation. It required dissassembling the fan to remove the blower assembly from its housing, to make the unit lighter and easier to manipulate for mounting.

I had to cut a bigger opening in my ceiling and take a dremel to remove a nail sticking out of a joist that was left over from the original fan installed in the house. Fortunately, I was able to do most of the installation work in the bathroom from below the opening of the ceiling, because it was deadly hot in the attic.

And then, after having had several previous successful efforts to rewire other bathroom fans to accommodate new types of switches, I was careless in figuring out the wiring this time and blew out our house circuit breaker. We almost had to replace it, but after it cooled down it started working again.

This time, carefully checking with our multimeter I finally figured out the correct wiring configuration, and it worked.

But then my husband said he wanted to be able to switch the fan off, so I swapped out the single button light switch to a double button switch (for light and fan) and had to rewire the whole thing again, completely differently. Good thing I have an engineering background and can do wiring diagrams in my head. A fun mental challenge.

When the fan is on, the sound reminds me of being in a hotel room in a highrise that has the ventilation on all the time, i.e. it's basically background noise, fairly quiet. The fan has an occupancy sensor to automatically kick on when someone enters the room. I'll try adjusting the "occupied" setting to run at 50 cfm for 30 minutes to see if the noise level goes down to where you have to strain to hear it. The fan has a little green light that flashes on when it is detecting you, as you can see in the picture.

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