Thoughts on cold/hot air return venting

User

9 years ago

last modified: 9 years ago

My home was built in 1986, so maybe this is a 1980's thing. I have 3 return vents.

#1 is upstairs in hallway

#2 is in family room

#3 is in basement but routes "outside"

The #3 is a smaller duct, so I would guess its pulling 20% fresh air from the outside into the unit.

I've poked around google & the information is conflicting. Most say that it puts more stress on the unit, as in Ohio we sometimes hit zero degrees in the winter & do have some 90 degree days in the summer.

I'm not an allergy sufferer & sometimes it's nice to have fresh air in the house, but I've never seen this setup before in any other place I've lived.

So is this just a fad from the 80's, like parachute pants & Gee Your Hair Smells Terific shampoo or is there some useful, purposeful reasoning behind it?

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PRO

Austin Air Companie

9 years ago

weidmeister : ok.

The oldest areas I tend to work in are builds from the 80's so I don't see these kinds of set ups like I used to. I think this was more common in the 60's and 70's. Once early 2000's came around the controls were available to operate these via damper and controls typically placed in blower section to control the damper. Most homes in areas I service from the mid 80's to late 90's do not have the fresh air intake... probably because they started to realize the trouble with those of earlier times.

Many times I find these controls either off or disabled because in my area it's rarely that good outside to let the out door air in. If the house is really that tight you're probably better looking to a HRV or ERV for fresh air. Or let the homeowner crack a window on their own.

In JeCriglers climate it's probably a toss up. As far as the hops smell goes you might still smell that even with no fresh coming in. When I was a kid growing up in Wisconsin we had the Nestle plant. (chocolate smell)

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Comments (11)

PRO
Austin Air Companie
9 years ago
There are homes around this area with similar attributes minus the basement.

The idea was to pull in fresh air, problem is that the technology didn't exist then to close this vent when temps were not favorable. It is typically just a manual vent unless the vent was upgraded with a powered damper with control to operate it.

80's style of home is no where near as tight as one built today so your home air exchange rate is typically high enough to where you really don't need this 'so called' fresh air vent.

Given your location the detriment is probably quite small except during extreme weather conditions, You could test it by closing this vent and keeping it closed and see if you notice any difference. In some cases I've seen over the years some didn't even have a manual damper. If that's the case with yours then you won't be able to test it that easily... find the end of the vent and plug it up / or chop into it and plug it that way.
mike_home
9 years ago
You should not be pulling in outside air into your HVAC system. I suggest you seal it.
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klem1
9 years ago
Wherther you should or should not pull outdoor air can depend on things other than your comfort and utility cost. Engineers often want positive pressure to address backdraft fron other appliances or other concurn. You should have a pro check the place before perminatly stuffing rags in the pipe. Assuming there's no need for positive pressure,I have comments in favor of doing away with it or as A. Air mentioned,controling it with a damper. About 75% of fresh air ducts I've seen were down stream from filters. If you are going to run one I recommend it be filtered which often requires installing a dedicated filter. If it's needed only when a certain appliance is running,it's not expensive to have that appliance control it with power damper as Austin mentioned.
weedmeister
9 years ago
If this is a gas furnace, are you sure this isn't a combustion air vent?
PRO
Austin Air Companie
9 years ago
last modified: 9 years ago
If the pipe runs into the return of the HVAC system it's not for combustion air.

to this day, people still do not read in a forum board.

'I have 3 'RETURNS'... #3 goes to the outdoors.'

Now if #3 is not attached to the return then it's not a return, but that is not what was said.
User
Original Author
9 years ago
Yes, I also have a gas furnace attached but this pulls air inside whenever the fan turns on. The duct feeds in through the basement ceiling and goes right into the big huge pipe/duct for air return going straight to the air filter. I could easily disconnect part of it and let it pull air from the basement instead, but I figured there must be some sort of logical reason for this set up adding fresh air to the mixture.
weedmeister
9 years ago
AA: I just wanted to clarify.
User
Original Author
9 years ago
Like I said, the fresh air is nice....most of the time. However we do have an occasional skunk spray the neighborhood & that gags me when it blows inside.

Also, I live 5 miles from the Budweiser plant. During the night, if the air is thick & breezy I do smell the hops.

Or my dogs will go #2 under the vent outside in the grass. Have to clean the up immediately.

But on normal days I don't mind.

Rays theory about the vent closing & opening does make sense tho, but no mechanicals are installed for that to happen unless I do it myself.
User
Original Author
9 years ago
I'd prefer chocolate to hops.
Vith
9 years ago
last modified: 9 years ago
I was considering fresh air hooked to the return, but then I thought of the ultra cold winters and how that would affect my heating and also the positive pressure in the house would push all the conditioned air outside. Instead I installed make up air with a passive damper in the dryer room that lets fresh air in when vents are running (dryer, bath vents, range hood). My house is fairly tight during the winter (less tight in summer due to removable storm windows), so I get fresh air when I run vents. Either way when you push air out of the house you pull air in (and vice-versa). I dont have passive gas appliances so I dont have to worry about backdrafting. If I did install gas appliances they would be power vent, I am not interested in messing with the whole backdraft situation or having undampered open holes to the exterior. When I moved in I had a standard flue with a gas water heater, and I got rid of the heater and flue when I re-did the water lines, used electric so I could place it where I wanted, monthly bill ended up being similar.
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