Furnace efficiency ??? Should I be heating the basement ???

Question

I live in an 1100 square foot ranch in Michigan built in 1942. The furnace is 20+ years old and is located in the basement. Currentlly I have all the heat ducts in the basement closed off. Should I be heating the basement for maximum efficiency ??? Also, would humidifying the air in the basement help ???

Answer 1

I live and build homes in Alaska...I don't insulate the basement ceilings and would NOT recommend you add moisture to your home. In the cold weather building classes we must take up here...one thing stands out...you need to insulate your foundation walls...this keeps the cold air from penetrating in on the bottom, cool air is heavier,so when it pushes in, your hot air is forced out, because it is lighter. we use a r-19 on the walls with a 6-mil poly sheet in the crawlspaces(on the floor) with 24'' laid flat around the footer, or perimeter.we don't vent any heat ducts in crawl spaces....If your home is 5-star ...you need to regulate the humidity with a DEHUMIDISTAT..so it won't hold in moisture...a house that old will not be that well insulated...check to see what is in your walls and ceilings...insulation has come a long way in 70yrs.....

Answer 2

A 20 year old furnace is most likely around 65% efficient. YOu do not have to heat the entire bsement, however most people keep a little heat in that area
Adding a whole house humidifier to a furnace adds mositure to the heat and is more comfortable.
You can replace the furnace with a new 80% furnace for around $2000.---$2500. If you install a 90-96% unit you will cut your fuel consumption by nearly 30%. Those units normally cost about $1000 more than a standard furnace but arer well worth the investment if you are going to stay in the house for at least 5 more years.

Answer 3

It depends on where the furnace gets its air from, how much insulation there is between floors and in the walls downstairs and how the heating air is recirculated. There is a very slight increase in efficiency if the air drawn into the furnace for combustion is warmer, but the difference between 40F and 70F is negligible. On a furnace that old, it unlikely that vent heat is being use to preheat supply air.
Usually, the furnace collects cool air from the house and blows it back into the house heated. If the return air loses a bunch of heat in the basement ducts, less efficient.
And if the ceiling of the basement is uninsulated then you are walking around on a cooler floor while the heated air is around your head and higher - not comfortable.
Furnaces you can buy today with have much higher efficiency than old ones. We just put in a 95% furnace that wrings so much heat out of the flame that it condenses the water from the flame products (and must have a drain) and vents through PVC pipe that may vent up or sideways through a wall while preheating the supply air somewhat.

Answer 4

I live in a similar situation. not heating the basement will keep your cost down. You shouldn't need to humidify the air in the basement especially if you are not heating it. I heat the basement because it makes this space more comfortable to use and almost doubles my living /working area. A cool mist humidifier will make your upstairs more comfortable. Some say that the more humid air allows you feel warmer and I agree.My plants also agree with the added moisture. The furnace add-on humidifiers seldom work well if at all.

Answer 5

theres a lot that goes into answering that question. 1. is any of your basement finished? Do you have a washer or dryer in your basement? Are you using the basement for anything besides storage? If the answer to any of those answers is yes then you should heat your basement if not leave them closed and you should also insulate your basement ceiling. Having your ducts closed in your basement shouldnt affect the efficiency. If you do decide to not heat your basement you should also look into getting your duckwork wrapped with insulation.