fresh air into hvac


  #1  
Old 01-11-04, 09:31 AM
timwash
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fresh air into hvac

My question:

Our house was built in 1989 with a Trane forced air furnace and air conditioner. It gets awfully stuffy in the sinter time...stuffy noses, etc.

My question is whether I can (or Should) cut a hole in the return plenum and attach ductwork or pipe that allows outside air into the system.

there is currently no fresh air entering the system...just recycling the same air.

any thoughts would be appreciated

Thanks,

Tiim
 
  #2  
Old 01-11-04, 10:12 AM
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Lightbulb winter time

Before I think air from the outside in the winter time Id look at a good power humidifier on that furnace. It will make you lower the tstat some and also get that stuffy nose out of the way. ED
 
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Old 01-11-04, 10:54 AM
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absolutely go with the humidifier as ed says, fresh air will add to the heating load, and you can put in a humidifier for @100 to 150 yourself, easy and we can help
 
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Old 01-11-04, 04:39 PM
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Before we jump into the Humidfire, how dry is the home? Less then 30%?? If it's less then that, then put one on.

Down on OK, it's not that cold for heating load, you can attatch the fresh air vent into the return duct.

I put a damper into the fresh air line, so you can close it down if you run the fan all times. and close it off in the summer to keep the heat and humdity out.
 
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Old 01-11-04, 05:52 PM
timwash
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thanks for all of your input...I have a whole house (tank type) humidifier that we run all winter. It seems to help. The only problem about attaching a humidifier to the system is lack of water supply and drains.

Thank you for all your advice.

How large should the opening be to allow the fresh air to circulate?

Tim
 
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Old 01-11-04, 06:52 PM
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We use 5" up here in MN 5" should be good enough, don't want too big.
 
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Old 01-12-04, 06:40 AM
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Lightbulb make up air

Lets think about it. You go around the home. New doors, new windows. seal and caulked ,more insulation.Then you want to cut a 5" hole for air from the out side????????? Over the years we have found its not worth it. Also when you bring in out side air with the high humidity in it you warm it so it expands and you end up with less humidity in it.I have had the intake pipes ice up inside the home then melt and water run all over . Just the way we look at it.
ED
 

Last edited by Ed Imeduc; 01-12-04 at 08:27 AM.
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Old 01-12-04, 05:58 PM
timwash
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Ed:

Don't most of the high effeciency units that are installed today have some sort of fresh air return???

I know a an air exchanger exists...so it cna't be a new concept.

It is humid here in Oklahoma most of the time...except winter...it can be dry as a powder house.

Thank you for your input.

Tim
 
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Old 01-13-04, 06:56 AM
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Tim,

You can add on an Air to Air Exchanger if your buget allows you to do so.

Air to air will temper the incoming air for your home, and pulls out the stale air.
 
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Old 01-13-04, 08:28 AM
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Lightbulb Vent air

The units with a high AFUE take their air from the out side and say blow it out. What you said is "stuffy noses" Now as I have said to take outside air in you wont get the humidity you need here and that is what you need.
There are many humidifer out that you can put on the furnace that dont need a drain for them . Just a 1/4"water line to it. Know OK spent time there in Enid ED
 
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Old 01-13-04, 09:42 AM
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Houses in the South Central areas are dry in the winter because they're designed to shed moisture. In the warmer weather, the design is advantageous. For the few days when temps drop and the air becomes desert like, we suffer. It takes a ton of added moisture to get a Texas house (and I'm sure an OK. house) up to 30 percent humidity. It goes out almost as fast as you can put it in. If you do succeed in getting to a comfortable humidity level, you'll have water running off the windows. Bringing additional dry air in from outside via the existing furnace intake will add to the problem rather than help solve it. It will also cause additional much bigger problems (some of which have legs) in the summer. Please don't put a hole in what should be a sealed system. If air quality is a big concern, add a heat and humidity recovering air exchanger with it's own duct system. Expensive? Yes, but cheaper than the mistake you're about to make otherwise.

The problem described sounds more like a dry air problem than a quality problem. The solution is really a compromise: Add as much moisture as possible, use saline spray/gel in your noses and live with the rest of the problems knowing that your house is well designed to fight off the warm humid air that is upon us for the majority of the year.

Doug M.
 
  #12  
Old 01-13-04, 03:04 PM
binford
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keep it simple. I crack open my windows durring the day to get some fresh air in the house if needed.

You might want to look at Fantech Heat Recovery Ventilators. I would look at the SHR Models http://www.fantech.net/hrv_erv.htm

Heres a web page that you can buy one at
http://www.hvacquick.com/frhrconfig.asp?fm=HRV
The SHR1504 is $544.00

Another option you might want to look into would be a UV Lamp.
 
  #13  
Old 01-13-04, 03:44 PM
timwash
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Thanks much for all the advice. I have been convinced NOT to cut a space in the return for a fresh air return.

Just pray for rain, add another humidifier, and open the windows occasionally.

Once again, thanks to all for very sound advice.

Tim
 
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Old 01-13-04, 04:01 PM
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look into getting a water supply (can use a BPV, seen on many icemaker installs) for supply, and drain where a/c evap drains...put in a humidifier, and you will not experience those dips in humidity. interesting info from other posters, conditions and the way we deal with them seems to vary from region to region. what do you neighbors and friends do about the problem in their homes?
 
 

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