I haven’t posted lately because an electronic project that I worked on for much of 2017 and into 2018 occupied most of my spare time. Unfortunately, it hit a roadblock (cost of FCC compliance testing, not technical) and my attention was then diverted to more domestic pursuits (one is topic of this post). I do have a new electronic project, in fact I’ve already produced a PCB for it – but – it’s not time to talk about it yet. I did not post about the previous time-consuming project because it, and also the new project, have a commercial aspect and thus I am not prepared to disclose details about them, at this time.
Anyway, this post is about a recent domestic project. It isn’t electronic but you “may” find it interesting nonetheless. I live in the North Carolina mountains and it is cool enough that the air conditioning is seldom needed. In the summer, some afternoons between 3PM and 7PM it can get warm enough that air conditioning is needed. My home used to have a Tamarak HV1000 Whole House fan that I pretty much disliked. It seemed as loud as an airplane engine and provided minuscule air movement. Last year one of its two direct drive electric motors died and it is not a serviceable item, per Tamarak. BTW, to Tamarak’s credit they have added quite a few new fan types since my HV1000 was purchased about ten years ago, but they cost more than the solution that I selected.
I opted for a self-install Quiet-Air 4800 fan which is pretty quiet – maybe 5%-to-10% of the Tamarak’s noise level and exchanges air at 3,500cfm. It was expensive but my house just doesn’t have a good place for the cheaper old, traditional horizontal attic fans (which are also quite noisy). Some photos of my QuietAir install are below. I deviated slightly from Quiet-Air’s instructions, as follows: (1) QuietAir provides two steel mounting arms1 that are screwed into a ceiling joist and the damper box is supported on one side by screws into the ceiling joist and 2/3 towards the far side by the two mounting arms. This is OK except that one side of the ceiling grill would be supported by screws into Sheetrock, which is not acceptable to me. Thus I framed around the damper box with 2X4s primarily as support for the ceiling grill, but it also allowed better support for the damper box by screws into the 2X4s; (2) I used aluminum HVAC tape to seal around the damper box to sheet-rock seams, and also the flexible duct interface to the motor and damper-box so that absolutely no suction power was lost; (3) I added rubber washers to the fastening lag-screw that secures the motor support chain. The idea was to mitigate any vibration being transmitted to the rafter. Vibration turned out to be undetectable so the rubber washers are probably unnecessary. Click on photo thumbnails below to view larger. Click the enlarged photo to step to the next photo.
- QuietAir would significantly improve their product if the damper box support arms were lengthened and shaped at the far end with a horizontal section pre-drilled and tapped to accept the grill attachment screw. In this way the grill would not need to be supported by Sheetrock. See Figure 1, below.