Is This A Source Of Heat Loss In My House?

[StihlRockin']

There is a vent on the top of my house and I always just thought it was a typical vent for attic ventilation. I got to thinking just tonight about something. There is an exhaust over my stove for fumes, smoke, etc. There is a fan mounted there inside, but haven't used it in years as it quit working. Sort of like a hood. I see above the stove in/beside the wall part of the exhaust duct work going up. I assume it is the only exhaust port to the roof vent. I could be wrong. The roof vent could also be hooked to the attic so the air in there can be extracted. Not sure.

Anyway, if that hood over my stove, with the broken fan mounted inside is the only source to the outside, wouldn't that be a draft source for air in the kitchen to escape? I do know every year that most of the snow is melted from around that vent exposing the roof.

I'm thinking the warm air inside the house is leaking out this vent 24 hours a day and with it being cold outside and warm inside, would create a draft sucking my hard earned warm air outside.

Should I just cover this vent completely? I could screw sheetmetal in front of the fan vent or even just duct tape it. What do you think?

StihlRockin'

 

[stihl sawing]

I moved this here, I believe you will get a whole lot more answers here instead of the OTF.

 

[StihlRockin']

I didn't think of that. Good idea.

Thank You!

StihlRockin'

 

[stihl sawing]

If you don't get an answer soon, I will move it back for you. but I believe these guys will help you out. I can help you some too. Yes that is a constant air leak. Since heat travels up it will go to the vent quickly. I would plug it up somehow especially since it don't work.

 

[Jim Timber]

Does it have a clear path for the air, or does it have some kind of shutters that open when the fan is running?

 

[farmer steve]

light a match under it and then blow it out. if the smoke gets sucked up through the hood then i would say you have a heat loss. it can be fixed with DUCT TAPE.

 

[Whitespider]

light a match under it and then blow it out. if the smoke gets sucked up through the hood then i would say you have a heat loss.

Verification is always better than guesswork... always‼
*

 

[NSMaple1]

Not only heat, but moisture too. That will condense when it hits the cold attic.

Verify with a smoke test. If you haven't even looked in the attic yet, you're doing a lot of guessing.

 

[StihlRockin']

If you haven't even looked in the attic yet, you're doing a lot of guessing.

Ok, ..."you're doing a lot of guessing."

Why look in the attic at the vent? To see if it also is attached or has an opening for venting attic air? I mean, if it was attached or not, what difference would it make to the vent above the stove that I thought was venting air from the kitchen?

I can see if I blocked the roof vent from up on top how that would be a mistake if it were an attic vent, but since I blocked only the part above the stove, I thought that would be good. Am I missing something? If I did check the attic to look at the vent, what should I be looking for and what should I be doing? Thanks.

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Ok guys, I did a verification smoke test. I struck 4 different matches and almost seems inconclusive. I wasn't real happy. Yes, "some" smoke seemed to be drawn up, but it wasn't in a hurry if you know what I mean. I looked behind the fan and there's no flap. The back of the hood had the opening to the vent that goes up to the roof. I wrapped the vent screening in front of the fan with aluminum foil. Worked good to block that spot off.

StihlRockin'

 

[cre10]

I would block it for sure.

 

[cprost]

IF you block it off do it above the stove. There should already be an anti draft device installed but most stop working after they get dirty. I don't think it would be connected to the attic vent, just dont know how that would work. But i have actually see a stove vent connected to a sewer vent and you dont want to block this off on the roof.

It could be a number of things. Do you have multiple vents on the roof? Do they all look the same? The best solution would be to look in your attic to see what is going on.

 

[idahohay]

Why not fix the fan? Kitchens are a major source of bad air in your house especially if you have a gas range and actually cook on it. The proper flapper will minimize air loss and you could probably do some air sealing or insulation somewhere else.

 

[gulity1]

BOCA code says that you need to have a working fan/vent over stove/cooktop for smoke fumes etc, if I rememeber correct. As stated earlier that they usually stop working when they get dirty. I have a hard time believing that this is a source of suggifaiant heat loss in your house, what about your bathroom? Should be the same setup, glorified fart fan. In the kitchen the filters usually clog with grease from frying bacon etc ( you know all the good stuff). I do beleive that the filters are supposed to be cleaned serviced once a year most are junk throw aways. Then again I could be toally wrong on the code and who really cares anyway. Just food for thought

 

[StihlRockin']

Why not fix the fan?

Well, because first of all I haven't used it in over 10 years('cause it's broke) and haven't seen the need to use it. Also, thinking back in those 10 years and further, I have never seen people use theirs. It's an electric stove. Don't know where the flapper would be. Thank you.

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What am I suppose to see or look for if I look at the vent from inside the attic?

StihlRockin'

 

[cprost]

"What am I suppose to see or look for if I look at the vent from inside the attic?"

It is hart to say. As stated before according to most building codes all bathrooms and range tops should have a vent. These will ether vent out the wall or threw the roof. But especially in older houses i have see all kinds of things. The main advantage to have a working vent over the stove top is to remove the heat and moisture from the stove in the summer months . If this is not a concern dont worry about it.


The Flapper is usually located where the vent duct is attached to the fan.

 

[ppkgmsy]

Have you gone onto the roof and checked the vent pipe? More specifically, have you smelled it? Waste systems also have roof vents.

FWIW, my house has four vents. The propane kitchen stove vents out from the kitchen wall, the propane dryer vents out a back wall, the bathroom fan vents out a roof pipe, and our septic also vents out a roof pipe.

 

[stihl sawing]

Guess I should have read your post better, I thought you had a vent above the wood stove. We have one of those vent hoods over our cook stove. Don't think you're going to lose much heat there. If it don't work and you're not going to replace it just cover it up. Probably save more energy by insulating windows and other stuff than you will lose through the vent hood.

 

[Whitespider]

The roof vent is most likely an attic vent and has nothing to do with the range exhaust fan. Not all range exhaust fans vent to the out-of-doors, some just redirect the heat and humidity away from the cooking area. Those that do vent to the out-of-doors normally go through a sidewall, not out the roof. Think about it, if they vented up and out the roof there'd be no real need for a fan... draft would do the work.

...I did a verification smoke test. I struck 4 different matches and almost seems inconclusive. ..."some" smoke seemed to be drawn up, but it wasn't in a hurry if you know what I mean.

That's about what I expected you'd discover... and that's why I agreed with the verification test. Really, I expected the test to be conclusive. I figured it would conclusively show there was no heat loss. You're not losing heat out the range hood. In fact, if it does vent out a sidewall, there's a greater chance cold air would be sucked in... but you'd feel that, wouldn't you?

 

[StihlRockin']

It's not the vent for the bathroom or waste system. I see a pipe exhaust for that. When I did the smoke test, I wasn't too happy to not see a strong draw towards the vent. I think I saw some, but nothing that would worry me. I closed it off. I recall now a number of times when the wind would blow hard, I'd hear something in the area over the fan exhaust. I believe it to be the swinging of the vent flap. I'm thinking there isn't a strong draft up that exhaust because this flap is closed and only opens when the fan is running... like mentioned earlier.

The vent above the exhaust fan goes up, does a 90° turn horizontal for about 12", then another 90° up the vent I see. It is away from any sidewalls, so it seems it goes straight out the roof. To me it seems it would be appropriate to vent outside. Why? Are these exhaust system fans made to vent out the kitchen and into the attic... bacon grease smoke and all?

I have not gone into the attic nor climbed the roof to see the roof vent. I will though as there is melting around the vent on the roof and I'd like to know why. I do have poor insulation in the attic. I do have attic vents both on the roof and on the bottom of the soffits.

As for working on the windows for heat loss, I copy that because I know for a fact I need better ones. Because here now where I'm at when it gets to 10°, that's a warm spell.

I really appreciate the help here. I'll keep the stove exhaust blocked off, although I think it's probably not necessary. I will confirm the nature of the vent on the roof. I want to know where the stove vent goes to, etc.

Thank you.

StihlRockin'

 

[stumpy75]

The exhaust vent for the powered hood above the stove in my parents old place went straight up to a vent through the roof. So, yes, they do it sometimes. As mentioned, the flap should be normally closed, and that keeps most of heat in, but I'm sure it leaks some too. But if you are not using the fan at all, some duct tape would take take of anything leaking past the flapper.