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moneymgmt 06-08-2012 09:22 AM

Air return from dryer vent outisde?
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We've only lived here a few months and while watering the garden this morning it occurred to me that this dryer vent next to the spigot is on the opposite corner of the house from the actual dryer and it's vent. This vent doesn't even have the flaps that close, it is wide open. I went in the basement and it looks like this goes right into the cold air return. The return from the upstairs uses stud space half-way to the outside wall, so I think it could really be capped just past it.

Any idea why they would do this??

Rewound98 06-08-2012 09:56 AM

It's ventilation for your HVAC system and it's a good thing.

Definitely don't cover it up!

You should see a damper where it connects to the return.

You may even see an ERV or HRV at that location (heat/air recovery ventilator).

What type of system do you have ... thermostat, etc.

hvac instructor 06-08-2012 10:10 AM

good call. they are using that for fresh air. i dont think they are using a heat recovering system. the lengh of the pipe is to help warm the air up.

moneymgmt 06-08-2012 10:26 AM

Thanks for the responses.

We have a 30'x60' ranch, the unit is a 60k btu Carrier forced air natural gas furnace, on a very simple 3-button digital thermostat. The PVC vent and exhaust are 50' down the house, closer to the furnace. I understand why they would be so far away but I still don't understand why you would want outside air circulating through your returns, just seems less efficient. Too few air returns? I'll open it up, curious to see where the damper is.

hvac instructor 06-08-2012 12:43 PM

how old is the house? when new houses are built or remodeled, they
insulate the p--- out of them and then the house can't breath and the IAQ- indoor air quality is poor and the people inside are always sick.
years ago they didnt have to worry about this because of the leakage
thru the windows and doors.

biggles 06-08-2012 01:17 PM

when ever the supply fan runs it sucks in the days temps 10F or 90F might want to put a damper in by the AHU or cut a piece of wood to slide up into the hood there.... summer your returning 70F air and pulling in 90F air on that return mixing?winter 10F outside heating with a 70F return again....mixing and dropping the return to run the heat longer....$$$$$$ same as opening a window or front door

moneymgmt 06-08-2012 02:47 PM

House was built in 2004, 2x6 insulated exterior with 13" blown in above so yes, they insulated the P--- out of this house :) Makes sense, I'll replace it with a new cover that isn't broken and use screws that don't rust this time.... geez some people are lazy!

Thanks all!

biggles 06-08-2012 03:08 PM

if your going to block it up outside throw some insulation in there pack it....even convection thru the metal will end up being a pull...summer/ winter might want to disconnect just into the basement....just so you have an idea...commercial jobs as a Nordstroms store big $$$$ bring in 10% outside air 24/7 to keep the floor and customers fresh...that is bucks:wink:on the mechanical cooling and heating gas fired rooftops up in the 100 ton ranges...

Marty S. 06-08-2012 04:22 PM

Fresh air duct like that is to make up for the drier,microwave vent, kitchen vent, bath fans ect exhaust. Bringing into the return means the outside air gets filtered and conditioned before drifting through the house. Without it the air still seeps in but through cracks which can cause mold issues in the walls. Leave it alone.

hvac instructor 06-08-2012 07:56 PM

dont add a cover with a flap if your going to use it. air has to come in. if not stuff it with insulation like biggles said. at the hospital where i work we have units thats 100% outside air like surgury units.

moneymgmt 06-08-2012 09:14 PM

I am not covering it, I'm replacing the hood itself. In the pics you can see two corners have broken off already and it looks like crap.

wkearney99 06-09-2012 08:28 AM

And be sure whatever cover you use is designed to help keep the critters out of it. Even a square patch of hardware cloth would work. One with flaps, of course, would not work as you need the system to be able to pull air into it. Most flaps only open when air is being pushed out (like from a dryer). I'd certainly want to know how that should be insulated. Seems like a pretty bad idea to have an uninsulated, thin wall metal duct like that running cold (or hot) outside air inside your house.

It couldn't hurt to have your HVAC guys come take a look at it, if just to make sure it's not some half-assed mess left over from someone else's attempts.

moneymgmt 06-09-2012 10:04 AM

I won't use one with flaps built into because they'll go the wrong way but I will put some screen over it to keep the bees/wasps out. I'm certain it is original to when the house was built, put in when the HVAC was done.

Johnny'sHotDogs 06-16-2012 07:08 AM

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