To Heat, or not To Heat...

I have a finished basement, and have been trying to decide if I should leave the heating vents open to heat it a bit, or to close them (I have forced-air natural gas heat).

My instinct says to close the vents (only 2 of them for ~800 square feet of finished area), concentrating the heat on the more-utilized main floor.
If I close the vents, the temp hovers around 60 degrees. If I open them, the temp settles around 64-65 degrees.
I use the area sometimes--mostly for exercise, or doing small projects. I don't mind it being a little cooler.

Am I better off heating all living areas? Is it possible that heating the basement will cost no more (or possibly less?) than only heating the upstairs?
I have searched all over the internet, and found no good answers.
I suppose I could simply open the vents for a month, then close them for a month and see what happens...but, outside temp variations could skew the results.

Bob

Bob,

Your instincts are correct. You will lower your total heating bill by closing the registers in the basement. You can't raise the temperature in the basement by 4-5 degrees for free!

The tradeoff will be that the floor surface above the basement will be cooler and therefore less comfortable. So you may use slightly more heat to be comfortable on the first floor. The overall heat used will be less, though.

Yes, I would agree with Lou. Assuming your thermostat is on the main level, the heat going to the basement could have been redirected above ground which would turn of the thermostat sooner.

LMU

Thank you very much, LouRoy.

This is exactly why I love this site--many helpful, bright and kind people.

Bob

You could always put a space heater by your workbench for the really cold days.

My instinct would be to heat the basement. Some, possibly most, of the heat used there will find its way upstairs anyway. But more importantly, it will help keep the basement air dry so that mold and mildew will be far less likely to form.

Nikon,

You have a valid point if Bob lived "Way down south in de land ob cotton". But he lives in Michigan. In the winter, the air is very dry and cold. Cold air holds very little moisture and actually lowers the relative humidity of the house as it leaks into the house. If anything, Bob probably needs a humidifier to raise the relative humidity inside the house.

I am also assuming that the gas furnace is in the basement. Thus Bob's statement "If I close the vents, the temp hovers around 60 degrees." I think the basement would get much colder if the furnace heat was not escaping into the basement.

Unless he has a poorly constructed basement that leaks water, mold and mildew should not be a problem at 60 degrees.

What say you, Bob? :wave:

Point taken. Mildew is a real problem year round in Georgia.

The other thing to take into consideration is whether there is sufficient air flow through the heat exchanger with the extra vents closed.

In some cases (don't know about this one) your efficiency goes down if you close off too many vents. What happens is the smaller amount of air flowing over the heat exchanger pulls only part of the heat from the burner, leaving the rest of teh heat to go up the flue. The burner is on until the thermostat is warm, no matter how much of that heat is utilized at the burner. I don't know how to calculate the optimum airflow.

At a guess, if the rest of the house's vents are open you probably have enough airflow.

Daniel

Speakign of heat exchanger, we don't have one (the one that scavenges heat from the exhaust)..... Old furnace.

Yes, you are likely correct, Lou.

DRY, it is! Yes, I do use a humidifier during winter, and a dehumidifier in the basement in the summer. We don't have any moisture problems.

I believe the furnace can handle having the vents closed, because the vents were added sometime after the furnace (when the basement was finished).

I might do a little experiment: close the vents, allow the temp upstairs to hit perhaps 68 degrees. Then kick the furnace on and see how long it takes to get to 70. I will also time how long it takes to drop back to 68.

Then, I can open the vents, and repeat the test. Might give me an idea how much energy is going into the basement.

Bob

Living across the lake I would say it depends on how much your going to use it. If it is regularly I would leave them open, or I would open them if you think we might be headed for a nice snow storm. Having the basement a bit warmer will keep you house warmer longer and holds the heat longer then above ground spaces. But it does use extra power or gas to keep it warmer in the long run, but likely less then the above grund spaces.