Unused floor vents seeping cold air - what can I do?

daddyratty · 10-08-2010, 11:38 PM

Hello there,

We're in a rental that's a 2-story house originally built around 1936. The house we live in was definitely not all built at once, and one of the interesting nuances is creating a bit of a situation now that the weather is getting colder.

We have a great fireplace in the home (Blaze King), and right on the other side of the wall is an old fireplace. Both chimneys run within a few feet of each other in an unfinished/storage room in the upstairs. The fireplace's chimney is covered in bricks inside the house, which draws the reasonable conclusion that the room was once just part of the roof.

I don't know much about older homes, but is it possible that a plethora of floor vents in the downstairs are connected to this fireplace in some way? I don't see any other evidence of a more modern forced air system.

My main question is if there is an effective and safe way to plug up these vents. Evening temps are now in the mid 40's and lows where we live average in the mid-upper 20's.

**beenthere** · 10-09-2010, 06:29 AM

Do you have a furnace in the basement.

AllanJ · 10-09-2010, 09:15 AM

It is usually easy to close off floor vents using things like books, towels, welcome mats, plastic sheeting, (duct) tape, etc.

But first find out where those ducts lead. They could be needed return air vents to establish a flow for the warm air coming from the furnace and emerging from other floor vents.

When you light your fireplace, combustion air is taken from the room. Makeup air must come from someplace and may have come from those floor vents and may have otherwise been unheated air.

daddyratty · 10-09-2010, 01:50 PM

The mudroom has a hole in the ceiling that constitutes a THIRD chimney in the house for a diesel furnace that has long since been removed from the house. So I think at one point there was a furnace system in place.

But these vents do not connect to anything active today.

Do I understand correctly that I should be able to seal these up with duct tape and/or plastic sheeting?

**beenthere** · 10-09-2010, 06:11 PM

Sounds like they were for the furnace at one time.
Yes. you can cover them.

What is the homes primary source of heat. A fire place is not allowed by code to be the only source of heat.

AllanJ · 10-09-2010, 06:15 PM

If the ducts currently go nowhere (are open at the other end) you can simply cover their floor registers with plastic sheeting taped in place (or cover them in any fashion).

Right now you probably just have cold basement air drifting up through the ducts.

daddyratty · 10-10-2010, 04:23 PM

Quote:

Originally Posted by beenthere

Sounds like they were for the furnace at one time.
Yes. you can cover them.

What is the homes primary source of heat. A fire place is not allowed by code to be the only source of heat.

It's actually a woodstove (does that make a difference?) that is the only source of heat in the house. There is no electric heating source in the home.

And I did cover them up by taping the inside of the registers with duct tape and simply replacing the covers. Seemed to make a BIG difference already.

**beenthere** · 10-10-2010, 04:41 PM

Around here. An apartment, or house couldn't be rented out with a wood stove as the sole source of heat.

daddyratty · 10-10-2010, 05:27 PM

Hmm. Well, this is a pretty rural area (practically "frontier"), and the house was built almost 80 years ago, so perhaps those are factors.

**beenthere** · 10-10-2010, 06:15 PM

Quote:

Originally Posted by daddyratty

Hmm. Well, this is a pretty rural area (practically "frontier"), and the house was built almost 80 years ago, so perhaps those are factors.

Not really. Just your landlord is cheap. And no one that counts knows it doesn't have an automatic central system in it anymore.

daddyratty · 10-10-2010, 06:21 PM

Wait, there is actually a Monitor heating system in the house. I forgot about it because we've already decided not to go the kerosene route.

Anyway, thanks for all the help and replies.