Whole House Fan (Non Electronic Post)

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.

 

  1. 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.
fan-arms

Figure 1 – Improved Damper Support Arm

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3 Responses to Whole House Fan (Non Electronic Post)

  1. Doug Drye says:

    So I have a couple of Dumb Questions… This Fan is single speed? Why wouldn’t it be at least Low-Medium-High? Also I assume from the dampers that it draws hot air up obviously out of the house just like most Whole house fans (where you have room for them)… I too have little to NO attic space in most areas of my newer place and have considered a whole house fan, but down here in N. Georgia at the lower altitudes (as you probably remember) the extreme humidity has caused me to re-consider. The humidity today is relatively low (67%) at 85 degrees, I can’t remember a day where it I felt I wanted to bring the humidity indoors as it causes most of the discomfort… As I recall, in the western part of NC, the humidity is not as bad at the higher elevations… Nice solution for a mountainside home, unfortunately not so much for us high humidity folk……
    Regards,

    Doug

    Liked by 1 person

    • celem says:

      [is] This Fan is single speed?
      – No, two speeds, low & high. Look at wall switch – two position rocker. The timer is the on/off.

      I assume from the dampers that it draws hot air up obviously out of the house just like most Whole house fans
      – Yes, same principal.

      I too have little to NO attic space in most areas of my newer place and have considered a whole house fan, but down here in N. Georgia at the lower altitudes (as you probably remember) the extreme humidity has caused me to re-consider.
      – Yes, it would be less effective in Atlanta. Our humidity is often in the 20-30% range, unless it is raining. However, it might be useful in Atlanta at night in the shoulder seasons. I used a whole house fan when I lived in Stone Mountain, Georgia – mostly at night – but then I have always disliked air conditioning.

      Liked by 1 person

  2. have an old (really!) fan controller with a temp sensor used with a test rack for tube (HEATERS!) type equipment from the 1970’s military surplus stuff. tear apart and find it looks like a common type wall switch light intensity controller. the fan that came with it was Rotron vane axial 120vac 60hz generic, (nice and heavy, sweet smooth aero designed blades and ultra quiet ball bearings). nicely adjusts the speed to the sensor (common thermistor?). possible way to evade the limitations of proprietary controllers? its smaller than an entire house fan (about 8 inches dia) but moves air like a tornado at full speed and slows to near zero when temp goes below about 60 farenheit. you might be able to use a standard wall type light controller for a variable speed on even these larger size fans, also, many common room fans (18-20 inch) can be flipped horizontally much like the commercial house fans and used similarly (no sheet metal housing, but that can be made from plywood or other). once the units are secluded from prying hands (children?) the grills can be removed and supports can be jury rigged and beefed up. these can be very quiet and will move large volumes of air even at the lower speeds. as for durability? many use those cheap bronze self lubricating sleeve bearings, but have had them last 10 years before they start to get sluggish. find a good brand with REAL sealed ball bearings and they might go longer or have a lubricating access point. metal fans are rare with the glut of imported chinese products, but some metal types can be had, even at swap meets, yard sales and (bulk waste pickup days!)

    Liked by 1 person

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