Latest Discussions : HVAC


06:30AM | 06/12/01
Member Since: 06/11/01
1 lifetime posts
I need some advice. I own a bungalow in Montreal. The main floor is slightly higher than street level and there is a finished basement. I heat and cool by central forced air electric, with a built-in humidifier. I have 2 returns on the main floor and 2 in
the basement.
Would it be wise to close off the 2 main floor returns in the summer so that the heavier cold air which is in the basement is circulated better and cools the house more efficiently? Conversely, should I close up the 2 basement returns in the winter so that the warmer heated air upstairs can be distributed better all around the house?

Just a note, I have also seen at a
hardware store an gizmo with a fan that gets inserted in the return space and depending on the season changes the direction of the air being circulated made especially for homes with 2 floors to better equilibrate the up and down temperature. Would this be an answer to relieve the colder basement and warmer upstairs problem that I have? The thermostat
for the entire house is located on the main level.

I apologize for the length of the post. I look forward to hearing from anyone familiar with this problem.


08:31AM | 06/14/01
Member Since: 01/28/01
171 lifetime posts
Mano99 - I would close the basement vents and open the main floor vents to get air moving through the upstairs. I would look into installing ceiling fans for a cooling breeze. Also check the attic insulation amounts and attic ventilation. It could be that a very hot attic is heating your upstairs. Adding more insulation, more attic vents, and an attic exhaust fan could help cool your house.


07:59PM | 07/03/01
Member Since: 07/02/01
4 lifetime posts
You definetly want the returns in the basement open - this will keep your humidity down in the basement. What I do in the summer is close off the output registers in the basement to try and get more cool air upstairs. I don't do any thing with the upstairs returns. I would think closing them would just get more of the cool air to circulate toward the basement - and if you don't have enough returns open you may end up putting out less air. You can only blow out as much as you **** in.


08:02PM | 07/03/01
Member Since: 07/02/01
4 lifetime posts
Apparently the word **** (s u c k)is censored? It changed to all ****. There are clean uses for this word.


11:10AM | 07/23/01
Member Since: 11/14/00
333 lifetime posts
The first poster is absolutely correct that you should NOT fool with the intake so as to reduce it. Most systems are designed for barely-adequate intake, and many are installed with inadequate intake.

Instead, I would close the output vents in the non-problematic zones so as to increase air flow to the problematic zones. (Close the basement vents in the summer and open them in the winter).

That said, and assuming that you have the rare "problem" of too much intake, you want to INCREASE air circulation in the problem zones, not decrease it. Thus, if you do close an intake vent, it should be the opposite of what you suggested in your question: close the intake in non-problematic zones, not in the problematic zones. Closing the intakes in the hotter zones during the summer will just allow the hot air to stagnate in those zones. Instead, encourage the system to draw that hot air into the system, cool it, and then send it back into the room.

That is why putting your car AC on recirculate ends up cooling your car ten times faster. Instead of pushing fresh cool air from the outside up against the interior hot air and passively cooling the hot air, you circulate the hot air through the AC system, and actively cool that hot air so as to remove the heat more efficiently.

If you close the intake in the problem zones, it will just take longer for those zones to cool/heat up. THAT is what really reduces efficiency.

As another poster advised, you do also want to be mindful of the stagnating effect of closing the intakes in the non-problematic zones. Again, I would not mess with it and would instead adjust the output vents (which would not cause the same stagnation problems because the system would still draw air in from the basement and send it up to the rest of the house).

[This message has been edited by Lawrence (edited July 23, 2001).]

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