Replies

1. 
   rjw | Jan 08, 2005 08:42pm | #1

   Google got me 18000 hits in less than 1 sec for "duct booster fan"

   Here's the first link: http://www.smarthome.com/hvacbooster.html

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   Sojourners: Christians for Justice and Peace

1. 
   OverKnight | Jan 08, 2005 08:52pm | #2

   Thanks, Bob. Your Goggle search words worked much better than mine; adding "duct" did the trick. Looks like I've found what I'm looking for. Thanks again.

1. 
   Hubedube | Jan 09, 2005 12:10am | #3

   do you have return air in these rooms. If no air moving out (return) ,it make sit difficult to bring (supply) air in.

    Also, a little "balancing" done to your duct take-off system may be the answer.

    an a slight rpm increase  (notice i said slight) to your blower may just be the ticket along with possible balancing.

   Anything is better than installing these sometimes unnecessary 'booster' fans.

   The single zone systems usually were designed to supply the furthest outlets with ample air flow.

   i'm sure yours can be solved (corrected) without the boosters.

1. 
   OverKnight | Jan 09, 2005 01:56am | #4

   Thanks, Hube. No, each room does not have a return; there's one central return for the upstairs and two returns for the downstairs. Although I understand the importance of returns and everything I've read said for every supply there should be a return, I've never seen a house with returns in every room. It sounds like it would be messy and complicated to retrofit them, also.
   The blower motor was replaced just last year, and an increase in volume was noted with its replacement, so I don't see the blower as being part of the problem. I don't know how the speed could be increased; kinda sounds like overclocking a computer.
   I solicited quotes from six HVAC contractors a few years ago for a second upstairs zone. One contractor had suggested installing damper motors on all of the ducts, with a second thermostat for the upstairs. When the upstairs needed heat or cooling, the downstairs dampers would close and the upstairs damper would open, allowing the full blower output to go to the upstairs; if the downstairs needed heat or cooling, the opposite would occur. This sounded like a great solution to me, better than adding a second zone; what do you think? Alas, as with many of the contractors in this area, when it came time to put the quotation in writing, I never heard from him again.
   The duct blower fans sounded like a fast and inexpensive way to remedy this situation, at least until I can get someone here to install the damper motors.

1. 
   Hubedube | Jan 09, 2005 11:25pm | #5

     I'll bet you that the problem can be over come by a simple, (and a couple of work hours) by "balance technique".

   Unless these cold rooms have little or no insulation, by putting more heated air into them, they have to get warmer

    And you do'nt necessarily need a rturn for EVERY supply, but it would make for a better evenly distibuted air flow. (which appears you have not)

    Installing returns can be very easy and then again it depends on the conditions Have you actually checked to see what conditions you are up against.

    You would be further ahead by taking the $50 that one fan would cost and apply it to an hvac tech's visual on-site opinion as to any  balance/ return work.

2. 
   NickNukeEm | Jan 10, 2005 04:03am | #6

   Another option to balancing the heat/cooling load is to place manual dampers in each supply duct, then regulate each until you achieve desire comfort levels in each room.  A HVAC contractor would normally do this with a meter to determine supply velocity (or volume, I'm not sure).  My own system, 2 zones (one first floor, second upstairs) forced hot air is setup in such a manner.  Ironically, the rooms farhtest away are either coolest in the summer, or hottest in the winter and the reverse is true for the rooms closest to the A/H because the dampers need to be set so less is reaching the farther rooms and more reaching the nearer ones.

    

   I never met a tool I didn't like!
1. 
   OverKnight | Jan 15, 2005 07:27pm | #7

   Thanks, everyone.  Sorry I hadn't checked in for a while; work's been kinda rough.  It looks like I should call that HVAC contractor back and try to get him in here.  If balancing doesn't work, them I'll look into the motorized damper for two-zone control.

   Thanks again.

1. 
   reganva | Jan 15, 2005 09:39pm | #8

   Have you tried setting the fan switch on the thermostat to "ON" intead of "AUTO".  This keeps the air in the house constantly circulating.  It worked for a cold bedroom I had in my old house. 

1. 
   OverKnight | Jan 16, 2005 03:39am | #9

   That might work with systems that have variable-speed blowers, but mine doesn't have one. It sounds like it would be expensive to run the blower continuously. Will the thermostat turn the furnace on and off while the blower remains on?

1. 
   reganva | Jan 26, 2005 07:59pm | #10

   It works with any blower.  The fan stays on all the time and the furnace only fires when there is a call for heat.  I did notice that my electric bills went up about $15/month while letting the fan run 24/7.

2. 
   BossHog | Jan 26, 2005 09:53pm | #11

   Just a quick thought to add - I was taught when trouble-shooting anything to always check the obvious first. So I was wondering if you'd tried to check the duct in that room to make sure it wasn't plugged with something. Like a kid's toy, or anything they wanted to hide from their siblings, etc. It might be worth a look...
   Every great advance in natural knowledge has involved the absolute rejection of authority. [Thomas Huxley]

3. 
   OverKnight | Jan 29, 2005 07:19am | #13

   Good point, Boss, especially since both of these rooms were childrens rooms before we bought this house.I think my plan of action with be to 1) insulate the ducts leading to these rooms (they're exposed in the basement), and 2) get quotes for motorized dampers and a second-floor thermostat.

2. 
   hurnik | Jan 28, 2005 06:19am | #12

   I will say that I've tried the "leaving the fan on" business. It seems to work quite well in the summer, but in the winter here, it actually makes the house seem colder.Whether or not it really is, is a diff. story.Of course in the summer, leaving the fan circulating will also eventually draw the cool air from the basement and help "spread" it through the house and eventually "even" the temps out (but it can help "cool" the house without running the actual AC sometimes).