cold air return & radon issues

cold air return & radon issues

PostBy: pret On: Fri Nov 16, 2007 1:35 pm

Hi everyone,

I am simply amazed at what has happened to the temps on my first floor as a result of providing a very small cold air return to 'complete the air circulation'! I have an old stone house with a wood siding addition that was put on in 1917. There is only one door from the stone part to the newer part. This doorway joins a living room area with a wood burning insert (also the stairs to the second floor), with the formal dining room and kitchen. The formal dining room and kitchen have been by far the coolest place in the house since we began burning wood about 3 seasons ago. The degree difference was always about 8 to 10 degrees - ALL ON THE SAME FLOOR! I figured, after reading info on this forum that the culprit is simply no provision for air to circulate back into the living room area (contains the wood stove) from the kitchen/dining area. I'll add that even when 40 - 45 degrees outside, it was work to keep the dining/kitchen area at 70 degrees.

What I did:

I cut a hole in the bathroom floor (same side as kitchen, etc. but shares a wall with the living room with wood burning insert) underneath an old radiator (virtually unseen) at 1.5 inches in diameter and the same sized whole in the living room area beneath the baseboard unit. Note that these holes are along the same exterior wall and the only doorway connecting these two areas is on the opposite exterior wall (the house is a rectangle). I connected the holes with 1.5 pvc pipe with a 90 degree elbow at each end and a 30cfm blower attached inline. I didn't seal all the connections yet, but things are fairly tight.

What I'm experiencing:

After about two days, I am astounded at the temperature of the newer side of the house! It is consistently between 72 and 73 burning a small but hot fire! I now have only a 3 degree difference between the two sides of the house! How could a 30 cfm blower do that!!! I remember only last year that I had to be burning that fire so hot and filling the firebox so constantly that I had more coals in the ash than ash! I wasn't allowing the fire to subside enough to complete the reaction. Now, I am able to let the fire burn nearly everything, and I'm just putting in a couple small pieces every hour or two - not near the consumption as before, and getting better results! I was worried that the 30 cfm fan wasn't big enough... and I know I'm not moving 30 cubic feet because the outlet for the blower is only an inch, and I'm using a 1.5 inch pipe to traverse the air. Also, all the joints and so forth aren't sealed very well. But it's working!

I just want to thank everyone who has commented on these types of issues... I'm a believer.

On to another problem: radon. Anyone ever deal with or remedy a radon problem? Safe levels in my area of Pa is considered 4 units or less. Our recent test recorded a level of 8units. This is a problem, what's the best way to fix it?

Details: our basement slab was probably poured onto dirt. We live on soil that is primarily limestone and shale. Our basement in one corner - about a 4 X 4 foot section - is dirt, the rest is concrete. The basement is not all that tight... but that certainly is a relative comment. Only two windows - one is bricked shut and the other is shut with insulation on the inside (it's under the porch). The outside access door is not tight at all. I can see the outside.

Anything would be helpful.

Great forum!

Pret
pret
 

Re: cold air return & radon issues

PostBy: WNY On: Fri Nov 16, 2007 2:01 pm

Good job...!! Circulation is the key.

Radon, you won't get rid of it, but putting some type of exhaust/blower unit (in-line type) in the basement/attic etc... or depening on the slab, put a hole in it and pipe it thru a vent fan to the outside to keep the levels down inside the house/basement. Basically similar small blower with 2-6" PVC from ducted from under the slab. I would make sure it is a sealed type unit so you're not spreading the radon where you don't want it.....

Here a few ideas

http://www.infiltec.com/inf-pixr.htm
WNY
 
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Re: cold air return & radon issues

PostBy: Bob On: Fri Nov 16, 2007 6:41 pm

I have had radon and installed mitigation. The process of drilling the slab and using a radon fan to maintain a suction under the slab works well PROVIDED that there is a permeable layer--crushed stone or gravel--under the slab. If the slab was poured on bare earth this method will not work.

If the slab is in good condition one approach is to cut the slab all around the perimeter, dig out a ditch and fill with gravel and cover with concrete after installing perforated pipe in the trench. The perforated pipe is then connected to a radon fan that exhausts outside.

You also mention that an area of the basement has an earth floor--this is a possible path for radon infiltration into the house and mitigation will probably require that this area have a layer of gravel/crushed stone installed with perforated pipe and then a slab poured.
Bob
 
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Re: cold air return & radon issues

PostBy: rockwood On: Wed Jan 26, 2011 11:34 am

I've never tested for Radon at my place so I thought I should. This state has a 'Indoor Radon Program' that residents can purchase Radon kits for 6 bucks.
Anyone here test for Radon recently?
rockwood
 
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Re: cold air return & radon issues

PostBy: oros35 On: Wed Jan 26, 2011 12:57 pm

I need to get some cold air returns plumed in my house. I can easily have a 10 degree difference.

Solution for radon is dilution and ventilation. Or Isolating the source which is tougher.

I've never tested for Radon, but if it was a problem it would set off our radiation detectors here at work (nuclear plant) In some of our areas of the plant, we get a high enough radon concentration to set off the detectors. The radon gas is attracted to static electricity in your clothes. It is especially bad when the air is dry and static builds up. When you try to leave the area, you set off the radiation detectors.

How much is bad is up for debate. There are other sources of natural radiation that are probably worse for you than radon.
oros35
 
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