rry@homxa.UUCP (R.YADAVALLI) (12/05/84)
I am posting this article here as I could not find a more appropriate newsgroup. My apologies if it doesn't belong here. I am surprised that there is no news group net.home. Wonder if there would be sufficient interest to form a newsgroup. Anyway, back to the where I started... I am looking for helpful information on reducing the noise caused by the cold air return of our furnace. We have a split level house with a very small basement under the family room. The basement is approximately 12'X14'. Because there is not enough room in the basement for the cold air returns to be scattered around the house, there is a big (about 3'X2') opening in the foyer area which is connected to the cold air intake of the furnace. The furnace is only a two years old and quite energy efficient. Now, the problem. Every time the furnace goes on and the fan starts, the airflow is so noisy that it is hard to do things like watching TV or listening to music in the living area of the house. In fact, the noise is so loud that it can be heard on the second floor of the house. Of course, the house being a split-level doesn't help in blocking the sound from reaching the second floor from the first. It appears as though the single opening for the cold air return is not large enough. But, there is not much room anywhere else in the basement to provide additional returns. One alternative suggested by a friend is to make an opening in the basement wall that leads to the outside of the house thereby bringing in fresh air which is quite desirable. But, the amount of extra heating necessary to heat the cold air from outside to the room temperature makes me wonder how efficient this would be. His contention was that there is more Oxygen in the fresh air than in the recirculated air. Does anyone have similar experience or expertise on this topic? I would appreciate any suggestions and infromation such as books on the subject. Please mail the responses to me if you feel there would not be a netwide interest on this topic. Thanks in advance. Raghu Yadavalli AT&T Bell Laboratories Holmdel, NJ
zimmerm@ccvaxa.UUCP (12/09/84)
Your friend must work for the gas company. Do not bring in air from the outside unless your house is very air tight and then do so with a heat exchanger. This allows you to get fresh air into the house with a small loss of BTUs'. The problem you have does sound like one of high cubic feet per min. through a small opening. Is there no way to increase the size of the intake opening? Did the installer provide properly sized ductwork? Can the vent and ductwork be lined with insulation? Most hvac contractors should be able be to this. If there is not room in the floor for more vent space how about the wall down near the floor else where in the house. Several small vents will add up to a large addition in square inches of intake vent. convex! pur_ee! uiucdcs!ccvaxa!zimmerm ihnp4!
ron@brl-tgr.ARPA (Ron Natalie <ron>) (12/09/84)
Contrary to public belief, an airtight home is not optimal. Consider building a passive heat exchanger to bring in outside air... -Ron
mike@amdcad.UUCP (Mike Parker) (12/11/84)
> Contrary to public belief, an airtight home is not optimal. > Consider building a passive heat exchanger to bring in outside air... > > -Ron < Being uncreative, I can't think af anything truly funny to put here > A truly airtight home is as you say not optimal, it is a health hazard. A passive heat exchanger is a good idea, but, I'm not sure how I would go about building one. One of the problems is that exchange of heat is not really enough. Warming up cold, dry outside air and cooling off warm, humid inside air gets you a heat exchanger full of water and cracked furniture. Drainage for the exchanger is possible, but most efficient heat exchanger have narrow air passages between many plates and could easily clog with ice if poorly designed. A humidifier will save the furniture, but is noisy and a pain to tend. ( When I lived in Maine, ours ate five gallons of water a day, and the only air exchange was bad weather stripping ). I think it would be best to buy a commercial exchanger. There has been much talk on this in recent issues of "Fine Homebuilding". Commercial exchangers are available that exchange heat *and* moisture. If you think about how a heat exchanger, you can see how readily moisture is exchanged if the membrane is not waterproof. Mike @ AMD