Quote:
Originally Posted by BigNumbers
Sounds like you're not closing your exterior intake flap - should be closed (mostly closed) in the winter to stop this from happening.
|
Quote:
Originally Posted by Komskies
It looks like my cold air intake is around 12 feet away from the furnace and ties directly into the duct work. I assume if you have that valve and close it completely in the winter the furnace wouldn't have any issues running, you'd just be running it off of recycled air instead of a combination of fresh and recycled air?
|
Whoa Whoa, hold up here. You need to be careful here, I'm not sure I'd suggest closing off your vent until you understand your HVAC system fully. It is there for a reason.
Generally you should have a cold air vent coming in from the outside into the furnace room for
combustion air. This ensures sufficient air draw to ensure combustion gasses are going up and out the vent, and not being drawn back down to combust. (ie if you don't have this and have a closed off furnace room, the only source of air to burn would be air from the exhaust vent). So this can be dangerous to close off.
You will also generally have a cold air duct running into the return ductwork, this is
make up air, and is there to replace fresh air into the home as air is exhausted out. When you flick on your range vent, your bathroom vent, and even the furnace/hot water tanks run, these are again, sending air out of the house, and that air has to be replaced. Without it, air will be drawn into the house through various air leaks (doors, windows, vents), or (you guessed it) back down through the furnace exhaust ducting. Rule is you should have enough make up air capacity to compensate if you had all these things running at one time. You don't want your well sealed house to be drawing air from somewhere you don't, be it the furnace exhaust, fireplace flu, etc. You can dampen this line depending on needs and weather, but again, closing off totally I wouldn't recommend, and it will still be filled mostly with cold air since your damper will likely be accessible in the furnace room.
Any and all of these air inlets should be insulated, which should solve your problem while maintaining proper & safe operation of your HVAC.
If you are concerned about the amount of cold (combustion only) air coming in, you can get valves that are triggered to only open up when furnace is firing, which reduce amount of cold air coming in, but again, that is combustion only. I'd go with insulation, there is a reason 90% of new installs have both inlets installed wrapped in the fibreglass/black right from the get so. See BigNumbers' picture for example.