Gas and Oil Home Heating Furnaces - Duct Work - Returns

I live in a two story colonial house built in 1985. I replaced the heat pump/electric heat with a gas fired furnace and A/C two years ago.

In the summer time, cold air seems to get distributed unevenly. The master bedroom on the second floor can be freezing, but another bedroom right next to it will only be somewhat cool. Both rooms seem to be getting a good amount of air from the supply.

One thing I noticed is that the return in the master bedroom seems to be pulling a lot more air than the returns in the other rooms -- the return in one bedroom is pulling next to nothing.

I also noticed that when the A/C is running I get a lot of air pulled underneath the basement door (the furnace is located in the basement).

Each room in the house has its own duct work for the supply of air, but returns are shared and aren't completely metal. In many cases sheet metal is used to enclose a joist or a stud.

Is this a common practice? I can see how I could seal the sheet metal in the basement to the wood to make a tighter fit, but the the whole setup seems a little cheap.

I would like to seal the returns to get more even circulation and cut down on the air being pulled down into the basement where it isn't doing me much good in the summer time.

Would it be worth it to have actual duct work put in for the returns?

Panning of the floor joists for the return air is common practice in NJ and very legal and safe. Sealing joints always helps. Sounds as though you may need to balance the systems air flow. Check for air flow dampers at your supply runs. If none are present have them installed.

WillinNJ:

I agree that balancing the airflow may help quite a bit.
You don't say if the basement is finished or not and if you have a high efficiency furnace that uses outdoor air for combustion.

Here's some reading on ductwork: http://www.fpl.com/savings/hes/contents/poor_duct_layout.shtml
Let us know if you need more.

If you have high and low returns make sure the high ones are closed if they have dampers and the low ones are open. It makes a difference if you draw the cold air off the floor in the winter.

Thanks for the replies.

I have an unfinished basement and a high efficiency furnace that could use outdoor air for combustion, but it isn't setup that way. A PVC pipe runs from the furnace to the side of the house for exhaust. A second coupler exits at the furnace for air intake, but PVC wasn't run to the outside of the house. I don't know why the second connection wasn't made.

Is it better for the furnace to grab air from outside the house?


Also I will check for the supply dampers.

...and regarding the location of the returns, on the second floor the returns are high and on the first floor the returns are low

As I'm sure you know, cold air is heavier than warm air. If the cold air is allowed to remain on the floor, the comfort level is reduced. It is like a water heater with no dip tube. (Haven't we seen enough of that here?) The air is being recirculated from the ceiling and even if the supply is on the floor, you would have to be in the direct path of the air to benefit from it's temperature. And when you can feel the air moving, it is uncomfortable because of the evaporative effect.

Don't know exactly how to tell you to rectify it, but it gives you more info to use in your assessment of the problem.

Ken

Thanks, but can I take a step back and ask a few of questions...

GregH asked if I had a high efficiency furnace (I do) and if I have outside air for combustion (I don't, air is pulled from the basement). I could have this hooked up if there was a reason to.

-How does the air intake on the high efficiency furnace not being hooked up to the outside impact heating and cooling performance?

-Does this have some bearing on the large amounts of cold air being pulled into the basement during the cooling season (maybe during the heating season also, but I haven't checked for this)?

In the case of the room that is performing poorly, the register is at the floor level off of the wall and the return is near the ceiling on the other side of the room. This room seems to have less draw from the return then other rooms. I was thinking this is part of the reason it seems warmer than other rooms even though it seems like it is getting an equal amount of air out of the register. I though that looking to seal the duct work and "panning" would help overall and then look more specifically at the path from the underperforming room to the furnace.

-Am I on the right track?

Thanks all!