Turbine vent pumping fresh air to basement! - DIY Chatroom

Reilley · 09-03-2008, 11:26 PM

Hi all, I'm new to the forum and have a question about a strange setup in my newly-purchased home that has me puzzled.

I have a turbine vent on the lower roof of my side split that is piped to the basement. It blows fresh air into the basement. My in-laws, who live across the street, have the same setup. They have referred to it as a "Venmar" but it is like no Venmar system that I am familiar with.

I haven't been able to locate any information about this strange setup online... I'm going to cover it up for the winter as it gets pretty nasty up here in Northern Ontario and I don't like the idea of pumping cold air into my warm house.

Can anyone offer any insight into this? Thanks.

**thekctermite** · 09-04-2008, 12:37 AM

Strange. If you have fuel burning appliances in the basement it could be some sort of system to supply them with combustion air. If they're in a small room, lack of fresh air can be a big problem. Combustion air can be brought in from outdoors, but I never advise it because people do just what you're talking about...Covering it up. I've never seen a turbine vent to provide combustion air.

How big is your basement?

What is the btu/h input rating of the furnace (on the sticker inside the furnace access door)? Is it a high-efficiency unit with PVC pipes for vents? How about the water heater size and btu/h's?

Here, the code for combustion air is at least 50 cubic feet of room for every 1000 btu/h's of appliances. If the furnaces or water heaters are sealed combustion high-efficiency that get their air from outdoors, they don't need interior combustion air.

I'd suggest contacting the builder that built the homes to see if he can shed some light on the system installed in them. You might also post some pictures here!

8 Ball · 09-04-2008, 06:25 AM

Venmar is a major manufacturer of HRV or ERVs. Energy recovery ventilators. They are used in your part of the world to supply tempered outdoor air to your home whenever your bathfan, range hood or furnace operates.

Outdoor air and tempered indoor air that is being exhausted, pass accross a heat exchanger that transfers energy from one to the other, saving you money. These are normaly offered during construction as an add or extra.

Due to more energy efficient, tighter construction, the outdoor air is a requirement and keeps you healthy.

If it is just pumping air into the basement, and not an identifiable ERV or HRV, it is probably an attempt to satisfy the minimum code requirement for fresh air. Invest in an ERV or HRV and start saving some money,

Reilley · 09-04-2008, 09:12 AM

Thanks for the replies. I am familiar with heat exchangers. In 1981 (when the house was built) I'm fairly certain that minimum code requirements did not call for any such device. Does anyone know for sure?

The basement is large, with a high efficiency natural gas furnace (1991) and natural gas water heater (newer). It is a full basement (including under the garage, a good topic for another post). The house is about 1500 square feet upstairs so the basement would be similar in size.

The house was originally equipped with a wood/gas furnace (wood was stored under the garage) and a wood fireplace upstairs. Perhaps it provided fresh air for these? The vent comes out in the main recroom and the utility room is right off of that. On a side note, my in-laws with the same device were primarily electric heated, with two wood fireplaces.

Although I am all-for the idea of having a healthy home, I don't want to be flushing out warm air with unheated outside air. If I disconnect the hose at the turbine I suppose I can just use the vent for the attic.

Any other information / ideas?

**thekctermite** · 09-04-2008, 09:47 AM

OK, it isn't for combustion air in a basement that big. That's for sure.

I'm at a loss.

EAP · 09-04-2008, 06:43 PM

Just a guess, but is it for radon? Usually the gas is mitigated through an underground fan which sucks the gas (out) from underneath the slab. Or it is vented naturally through a passive pipe system.

Reilley · 09-05-2008, 12:27 AM

Quote:

Originally Posted by EAP

Just a guess, but is it for radon? Usually the gas is mitigated through an underground fan which sucks the gas (out) from underneath the slab. Or it is vented naturally through a passive pipe system.

Interesting thought, EAP. We do not have radon issues in this area though.

Reilley · 09-30-2008, 10:24 PM

It is a Venmar... I was up in the attic tonight inspecting the insulation and I gathered some information from the bottom of the unit. Here's what it says:

Venmar
Patent 1980 - 1095316
Item #60339

I can't find any info on it online. It basically looks like a white bucket with two connectors (one for each hose, to the kitchen and to the basement), and another hole in the side (for the attic maybe?). I may give Venmar a call to see what type of info I can get.

JamesK · 04-29-2009, 10:48 PM

I'm trying to find out about the exact same type of device in my own house. Reilley, did you ever find out anything more about it?

I assumed that it would draw the air out of my basement and hallway, unlike Reilley who claims that it pumps fresh air in from the roof. There are vents inside my house at the end of each of the two hoses, and they've always been closed, so this device has been essentially inactive.

This winter I had a small amount of water leaking through the ceiling at the vent in my upstairs hallway. When I checked in the attic, I found that the hose to that vent had broken away from the pail beneath the vent, and some water had collected in the low spot in the hose. I assume it was from condensation.

Can anyone shed some light on this device?

Reilley · 04-29-2009, 11:42 PM

It's been a while since I first posted on this topic. You are right in your theory that it pumps air out of the house as all turbine vents pump air out, at a rate of up over 1000CFM in 15-20MPH winds.

So the issue is that the process in which this air is pumped out creates a vacuum which in turn draws outside air in from leaks around doors, windows, sill plates, etc.

To say that the device could be turned off is not entirely true as vents do not form an air tight seal, especially under the draw produced by the turbine vent.

The idea behind exchanging air in this manner is a great one if you aren't paying to heat the inside air. Up here, in Canada, that only happens for a few months of the year.

I have disconnected the flexible duct work and sealed up the attic bypasses where it once ran. This summer when I have my roof done, I will be replacing the ugly galvanized steel turbine with a typical attic ventilating turbine vent.

Hope this thread was helpful. I was quite puzzled when I first came across this ancient Venmar system.

JamesK · 04-29-2009, 11:53 PM

Thanks for the quick response, it was very helpful. It's amazing how hard it was to find out anything about this setup.

Reilley · 04-30-2009, 09:55 AM

Quote:

Originally Posted by JamesK

Thanks for the quick response, it was very helpful. It's amazing how hard it was to find out anything about this setup.

No kidding! They are in plenty of homes up in this area too... Maybe Venmar realized the error in the their ways and covered up all signs of these units.

toofart · 10-18-2009, 10:31 PM

Quote:

Originally Posted by Reilley

It basically looks like a white bucket with two connectors (one for each hose, to the kitchen and to the basement), and another hole in the side (for the attic maybe?).

Thank you so much for that info. I have the exact same thing in my 1982 home, and had always thought it was a home-brewed. I now need to deal with it, since the bucket broke and it's lying on the insulation. I fear that attic air can now enter my home through those vents.