Cliff notes: looking for recommendations for a residential make-up air unit to reduce negative pressure in my basement.
I have been sealing up and insulating my older house to be more energy efficient, It is a two story home with a full basement in NJ, so it gets cold here. I have NG fired furnace, HWH in the basement. 2 kitchen exhaust fans, and 4 bathrooms with exhaust fans. clothes dryer on first floor. I just had a wood burning insert installed in my fire place so i can get the benefit of the fire place and heat without sucking my heated air up the chimney.
So i have a lot of appliances competing for air and some also oxygen.
So what i noticed was that when burring my new insert occasionally I would get the wood burning smell in my basement. Now since the insert is producing my heat and if i don't call for hot water the gas flu gets cold, with only a little polite light on the HWH to keep it warm. So with the negative pressure in the basement it was getting some of the wood flu air down it (single chimney with 2 flu)
When i call for hot water or the furnace calls for heat the flu drafts fine. It when it cold that the draft is weak. I learned to open a window or door when lighting a fire, or when i open the door to reload, spillage from the insert has not been an issue.
I just don't want to keep a basement window open all the time to reduce that negative pressure.
So what i am thinking is i should have a make-up air unit installed but i have no experience with them
Get a 6" dryer vent and take out the back draft damper. Install it somewhere and run 6" snap lock pipe to the basement. You can find a small fan at Grainger or McMaster Carr that is 6" round. You can then install a small 6" round grille to make it pleasant to look at. You can then wire the fan to a 110v outlet. There controls that you can get if you want to get fancy, ask at your AC supply house.
The HVAC/Insulation guy who i am working with is thinking I may want abandon my natural draft hot water heater and go with a power vent one or do a retro kit. The HWH is a 40 gallon tank and was installed in 2002. My gas bills in the summer for hot water and coking are very low so i don't see any return on investment from a tankless and running out of hot water has not been an issue.
From the documents the homeowners left the furnace looks to be an 80% York model installed in 2005. From what was being explained it is more sophisticated compared to the HWH, there is no pilot light, a sealed combustion chamber, there is a blower, etc, that getting any smoke smell down the flue from it should be mitigated or eliminated. The Y pipe to the HWH would be caped off.
He is going to come over Thursday and take some pressure measurements and use a blower door. We going to see how the gas flue behaves with the air handler on, off, opening a basement window etc. Normal they only test for when the gas appliances are on since they are only concerned with CO getting in the house when on, not when they are off.
The guy who put in my insert is going to see if he can get a taller liner cap to go above the gas liner cap as well, that should help when the wind blows from the wood flue to the gas flue.