Heat registers in unfinished basement - open or closed?

[Murdoc]

I bought a 1920's colonial over the summer. 1100 sq ft. The basement is unfinished, except for a half bath, which I never use. There are two heat registers in the basement coming from a natural gas forced air furnace. One goes into the half bath. The other is out in the middle of the basement pointing down from the ceiling.

They were open when I moved in, and my first thought about it was why keep them open and heat the basement when I'm never down there? But then I thought, why would someone go through the trouble of installing them in the first place if they weren't meant to be used?

Btw, even with these registers open, the basement is never warmer than 60 degrees when it's cold outside, even when it's 70 degrees upstairs.

Should I keep them open, or close them?

 

[boomerang]

Right or wrong I try to remember to close mine in the summer and open them in the Winter. I see no advantage to cool an already cool unfinished basement. I do see an advantage to inserting some heat into it in the Winter. But, we do go away for the Winter months and with the thermostat turned down, I feel it is even more desirable to have some heat being introduced into that space.

 

[MagnusTheBrewer]

If there's a door to close access to the basement, keep the door closed and close the registers. If there's no door, you could install one or a heavy curtain. Otherwise, leave them open to lengthen cycle times. Ideally, you do an empirical test tracking temps versus heating bills for a two month period with one month keeping them closed and one month keeping them open.

 

[Murdoc]

What would be the reasoning behind leaving them open or closed?

 

[nickbits]

I keep mine closed. No point in hearing and cooling an area I never go in. Even with them closed, the temp is fine.

 

[MagnusTheBrewer]

If you leave them open AND there is airflow between zones, the furnace should cycle less often because there is a smaller differential between temps. If there is no airflow between zones AND any thermostats in the basement are turned off then, it makes sense to close the registers so as not to lose heat for the upstairs zone.

 

[Greenman]

The correct answer is that none of us can know without doing a manual j calculation. With a whole bunch more information it's possible to make an educated guess.

Where is this house? We need summer and winter temperatures.
Is the basement insulated and finished?
Is there a moisture problem in the basement?
Is the basement ventilated?
Was it designed as conditioned space or was the heating added at a later date?

 

[edro]

I opened a few in my old unfinished basement just to keep air circulating down there.
We had a dehumidifier down there, so my thought was that it helped circulate the air.

 

[utahraptor]

My concern with closing the registers would be about Radon gas. I am not sure what effect negative or positive it would have to not allow the air to circulate as much down there.

 

[tsiunltdus]

I have an unfinished basement that is all concrete. I do get moisture in it at times so I Put one in my basement to help with the moisture. I do have a dehumidifier also in the basement. So it basically for air circulation in my basement. I live in the Ohio area so the temps get cold through the winter. I don't use the vent to heat as much as circulating the air for the moisture content in my basement.

 

[Exterous]

I keep mine closed. No point in hearing and cooling an area I never go in. Even with them closed, the temp is fine.

If you have pipes that run along the foundation wall it can be a good idea to heat the basement so they don't freeze

 

[NoTine42]

Unfinished concrete basement walls are going to suck up a ton of heat, so it makes little sense keeping a basement temperature above 60 if you are not using it. Get an indoor/outdoor digital thermometer and put it down there (most have min/max reading)

Unless you have an extremist low frost line, the floor should remain above freezing.

I have hot water radiator heat, with pipe insulation on the pipes, and I have my basement radiators closed. Our high temperature outside was about 8F today. My dehumidifier still shows 61F down there.(it shows temp and humidity)

If you just have sheet metal ducts, they might leak more than enough for the basement. If you have really nice, fully sealed and insulated ducts, you might let the vents open a little.