[kennykenny]

Cold/hot air is entering back into my house, from my exhaust hood over my stove. With recent subzero weather, the cold air has entered back into the house back through the vent and through the filter and dripped down onto the stove below.

Is there anyway of preventing the outside air back into the house? I have attached a picture of the vent(kind of hard to see) that is on the outside of my house. Are there alternative vents that might work better or other ways to prevent the air return? Thanks!

 

[Windows on Wash]

I was at a home yesterday that had a spring on the exhaust vent. Might have been DIY homemade but it appeared to be working well.

 

[Fix'n it]

that pic is about worthless. anyway. can you get up there to look at it ? if so, how easy does the flap work ? if very easy, you can tape or glue some weight to it. and see how well the flap seals and if its clean.

i used to have that problem, but i couldn't do anything about it from the outside. so i just wrapped the filter with tin foil.

and there are nice units
http://www.luxurymetals.com/outside-vent-covers.html

 

[GAPossum]

I've been thinking about buying backdraft dampers from Tamarack for my dryer and soon to be bathroom fans. They get variable reviews on amazon but I think they sound like a good idea.

http://www.tamtech.com/Backdraft-Dampers_c_10.html

I'm not sure how easy they'd be to use in a kitchen. They'd have to be somewhere accessible for occasional cleaning.

 

[ProGreen]

It's been a while since I did my exterior hood vent selection.

One aspect I notice looking at your photo is the pitch of the exterior vent opening doesn't appear to be parallel to the wall but rather appears facing out at you. Wonder if wind might drive rain straight on. Most exterior wall hood blower units have both a bird/insect cage and as mentioned above, a damper somewhere along the run to keep prevailing winds during rains from getting into the duct system and beyond. The link provided above shows the dampers well. Do you know where the damper is? For example, mine is a butterfly type shown above and is above the removable baffles of my vent hood

At installation of the external blower vent, after the blower ring is placed in the wall opening, the blower is attached by six screws to the wall. All required screws on the back panel must be placed, so that any moisture that may get inside the housing won't leak into the house.

Perhaps you may wish to check these two aspects for potential help to your problem. Good luck.