question regarding forced air heating/cooling

dorota · 02-23-2009, 08:08 AM

Hello,
This is my first winter in my 3 years old condo in Toronto. I have a furnace located on a balcony (enclosed). When the furnace is on it is blowing hot air into the apartment but at the same time the cold air is coming through the return air duct. This return air duct is very large and even when the heating is off, it is the source of cold drafts when the day is windy and cold. There is no insulation between the outside wall and the duct and there are gaps.
My question is:
is it normal that the fan is blowing cold air through the return duct or is it because of air leaks due to lack of sealing and insulation?
Covering this return air crate would eliminate the source of cold air but is it safe?
Thanks for explanation>
Dorota

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**Markus Keller** · 02-23-2009, 08:38 AM

No it's not normal, there is a problem.
It sounds like there is too much air just for gaps/leaks in the ductwork. Are you sure there isn't a make-up air damper at the end of the run that needs to be closed?
If not, I would suggest buying some good foil tape and insulation board and getting to work.
Is there a HUM, if so maybe the air is somehow going through the bypass. If the return side is really 'blowing' you could have a heat exchanger or cross connection problem.

dorota · 02-23-2009, 08:56 AM

Thank you very much Markus. I am not familiar with this system so I just wanted to know if there is a problem. From your answer I see that I should contact my management and report it. I am not sure who is responsible for faulty heating system in my building.
Dorota

**Jim Luttrall** · 02-23-2009, 09:00 AM

Get an HVAC contractor out there and DO NOT START SEALING OFF ANYTHING! It could just be a gap that can easily be closed BUT it may be a combustion air vent that you are trying to close off. Your actions may cause incomplete combustion, carbon monoxide production and death

We cannot tell what your situation is without much more information and maybe some pictures.
This is a home inspector site and we tend to get caught up looking at details and assume the person asking the question has a basic knowledge of how things work and it this case you really need a professional to look at the situation and answer your questions.

dorota · 02-23-2009, 10:20 AM

Thanks Jim. I won't cover this duct but it is a source of cold air coming to my house from outside. It is like having an open window during the winter all the time. It is very inefficient system when the hot air is blown from one opening and the cold air is blown at the same time from the other opening. Because the previous owner was living with this for more than 2 years I thaught it is designed like this but now I am sure something is wrong and needs to be done. I just wanted a confirmation from you - experts that it is not normal.

**Scott Patterson** · 02-23-2009, 12:28 PM

Get some tissue paper and tape a few long strips on the top and sides of the return so that they are hanging down over the front of it and along the sides. Also tape a few pieces on the center of the return. This will give you am idea if and how much air is blowing into your home. Turn the unit on and take a look at what the paper is doing, then turn it off and take another look.

dorota · 02-23-2009, 01:33 PM

Well, I have just done it. It looks like it should be. When the heating is on, the return is sucking the air from inside, when it is off there is no movement of the paper. So I guess the system is working OK. The cold air is not blowing as I previuosly described it but it is coming from outside through this crate. This duct is not fitting tightly along the outside wall, there are gaps, so these gaps are responsible for the outside air leaking inside? The access to the back and bottom of this duct is very difficult but I think I should try to seal any gaps?

**Jerry Peck** · 02-23-2009, 01:51 PM

Sounds like air leaks, so try this:

Use blue painters tape (it pulls off without taking the paint with it) and tape 6" wide or wider strips of food plastic wrap over the cracks you suspect are blowing cold air in, then watch the plastic 'breathe' with the air movement in and out.

If there is no movement of the plastic, that crack/space/gap is not leaking air either way.

I've always used plastic food wrap as it is light and moves easily but does not allow air to permeate through it like tissue does - tissue paper works okay when checking for larger air movements, plastic wrap works for both large and small air movements - just leave slack in the plastic wrap so you can see it balloon out and back in.

dorota · 02-23-2009, 02:22 PM

Yes there are air leaks and it is directly connected with the wind outside. When it is windy and cold like today I can feel the cold air coming from the return crate. I think the builder who was installing this heating system did not care about small things like fastening the duct tightly to the wall. My concern is that, even if I correct it somehow, the whole furnace area which is on a balcony, outside of my living room, cannot be completely leaks-free.

Ken Kimball · 03-02-2009, 08:00 PM

Have you considered contacting a home inspector in Toronto. I did a quick search on the internet and see several listed.
You indicated that you are not sure of the installation.
So If a home inspector is not what you are looking for, then maybe a heating contactor or your utility supplier.

hope this helps,

Ken Kimball, COSA
The Carbon Monoxide Safety Assoc

dorota · 03-03-2009, 06:00 PM

Thank you Ken. I have contacted my building management. They might help. I did not consider seeking help from home inspector buying a resale condo last year. I would if I was buing a house. But now I see that even a condo can have problems like poor construction or installation of equipment. I am curious if there is any inspection of units after construction. Toronto is one huge construction site and new high rise condos are being built very fast, with this quantity, quality must suffer...