I reside in NY and above the stove had a hood that vented to the outside. I do not remember it being drafty. The vent or vent cap (not sure what you call it) outside does have a damper that closes. The vent above the stove was removed. A microwave was installed above the stove and vents outside. Now in the winter it is very drafty. Cold air is coming in through the filter screen and below the microwave also. It feels like a window is permanently open in my kitchen. It feels so much colder, I do not want to be in my kitchen to have coffee in the AM. The vent or vent cap outside not sure what you call it is closing when not being used. Vinyl siding was installed on the outside of the building and the vent cap and vent was supposed to be changed and the contractor just didn't bother, or doing what was in the contract But that is another story or should I say nightmare. Now it is hard to change the vent cap I was told due to siding being installed. The microwave was installed about 2 years before the siding, and cold air was coming in so I do not know if that really is the problem. I am probably getting cold air going out in the summer when the AC is on also. Who do I call in a HV or a microwave repair? I do not know what to do? Thanks

I live not too far from you but a bit farther north in Alberta. I have always had my hood vented outside and have never yet had a problem with crazy amounts of draft. It gets windy here, on occasion I might feel the suspicion of a draft, but nothing bad enough to cause that kind of freezing temperatures inside my house! And on occasion I can hear the louvers for my range and bathroom fans clanking when the winds are bad. At present my hood is vented directly through the rear. Since my hood is on an outside wall, the distance involved is really small. I don't typically have water on my stove overnight but that sounds like overkill to me. I keep my house at a toasty 19 degrees (Celcius, unfortunately I don't understand the Farenheit system at all, but it's a few degrees below room temperature) so water freezing on the stove should be pretty much impossible. I'm not an expert in the field so I don't have all the vocabulary but the wall louver on the outside of the wall is supposed to help prevent drafts. It's a little piece of metal that sits flush with the outside wall covering the duct opening, when the vent is on the air pressure forces it to open so the air can flow. There's a little plastic "roof" over it that attaches to the outside wall which prevents snow/rain from getting in. I'm sure there's an equivalent system to make venting through the roof just as worry free. If it were that bad none of us Canadians would ever be able to vent outside! HTH

I'd suggest reposting in the Appliances forum. That's where lots of ventilation discussions take place--and also where downdraft vents are widely viewed as not very effective, so beware. :)

It would be best to start any quest involving kitchen ventilation to study the literature, or at least study the many many threads here on the topic. I would prefer to write answers to questions that are based on my possibly inadequate previous writing than generate yet another long message covering the entire topic. You may wish to start with the "Hood FAQ" which can be found by searching. I believe it is listed under @opaone. Hoods are about capture and containment, and success in this depends on many factors, the most critical of which is sufficient air flow velocity at the hood entry to ensure that which is captured is contained and expelled from the residence. This velocity is independent of how many burners are running at once, but rather what the cooking surface temperature is plus plume heat augmentation by gas burners. In any case, the 100 CFM per 1000 BTUh is derived from certain standardized commercial hoods, not residential hoods. See the Greenheck Guide available at https://www.tagengineering.ca/wp-content/uploads/2015/02/KVSApplDesign_catalog.pdf for comparison between the 100 CFM per rule of thumb and the hood aperture velocity rule. I suggest 90 CFM per square foot of hood entry aperture, and this aperture needs to be large enough to overlap the rising and expanding cooking plumes. Let me adjust the salesman's statement: "...because the design pulls more air than a filtered/baffled hood of the same [zero static pressure rated] cfm [when hanging unattached to anything in free air]." Ventahood use squirrel-cage blowers that also perform the function of baffle filters, thereby eliminating that cause of pressure loss. However, as blowers go, they are more susceptible to other pressure losses than conventional blowers, and hence if there is extensive ducting, or inadequate MUA, their flow rate will be less than the actual rate asserted. My guess is that you should have a 24 x 42 inch hood aperture, requiring an actual 630 CFM obtained from a 900 - 1000 CFM rated blower. Read MUA related threads to determine how closely the interior air pressure has to match the exterior air pressure for safety. Your state may require heated MUA. There are a lot of ways to accomplish MUA under these conditions, and the threads here should help you understand what you have to tell us to allow better tailored help. kas