Unvented Heater In A Garage?

Thoughts? Thanks, Glenn F.

The heater does let off a small odor which can get annoying over time, and my metal tools do condensate if it is really cold. In my opinion it was one of the best things I have done.

I just suggest that everyone be careful, as my dad almost died with a oil furnace. He was sick from Nov. till April when he called me and said there was a oil film on a cup of water in the sink. In the process he quit smoking for the rest of his life. He had the flue we thought, it turned out that in his double brick chimney the inner brick had colapsed. The Co2 detector did not work, but no one else ever was effected including the grandchildren staying over at his house.

In the last twenty eight years I'v been on the EMS in my small town of (700 plus surrounding rural area) we have had numerous close calls, and a few deaths, they all say the same thing--I had no idea it was happening.

I test my detector very often, starting the car in the attatched garage and opening the house door for a second or two and it goes off.

From your own Iowa State University:

"How efficient are direct vent heating appliances? While the flame burns with over 99 percent efficiency not all the heat is available. Approximately 9.6 percent of the heating energy available in gas comes from burning the hydrogen which produces water vapor. To recover this heat, the water must be condensed. ******With an unvented heater, the water vapor condenses on room surfaces, which increases the potential for wood rot, peeling paint, plaster failure, and mold growth.****** To prevent wet windows and walls, the vapor must be prevented from condensing, reducing the maximum efficiency of the heater to 90.4 percent.

Unvented heaters release pollutants into the house. Once combustion pollutants are in the house outside air must be provided to dilute and remove the contaminants. The additional ventilation needed to reduce pollutants to tolerable concentrations depends on the tightness of the building and the health of the occupants. Heating cold outside ventilation air reduces the thermal efficiency of the heater. The National Fuel Gas Code, commonly used in determining outside air requirements, is based on 1.0 air change per hour (ACH). Providing 1 ACH to a 10 x 20 foot room in Iowa would require over 1,000 Btu/hour, which is over 25% of the output of a 3800 Btu/hr heater."

With an UNVENTED heater, air exchange in the room is recommended, which obviously cools the room, and reduces efficiency.

SO, why not just run a VENTED heater in the first place!

• Source... Read this, and see how unhealthy unvented heaters REALLY are!

The AGA (American Gas Assoc) should have never allowed the term "unvented" or "ventless" to be used by the mfg's. Too most people ventless means just that, no venting of any kind is required when in fact that isn't true.

All carbon base fuel burning appliances have to be vented in some way. Doesn't matter if that's direct vented or active vented as without venting CO levels can and will become at a dangerous level. This is even true of catayltic and inferred heaters.

If your working on a project and start yawning or get a headache, is it because your tired?

Or is it because you have too much CO in your blood? Me, I'd head for the nearest door for some fresh air.

That's why they call CO the silent killer as it has no odor nor color.

Our local ABC news did a special last year on new CO detectors. 60% of the detectors failed right out of the box of the name brands tested.

I personaly don't have a problem with unvented space heaters but I also respect them alot and understand there limitations.

T_Bone

You could also go with a corn stove as they vent through the wall and don't need any fancy chimneys.

You will want to go to a power or gravity vent type unit heater that will keep flue gases separated from the conditioned space. Modine and Reznor are the most common types of these heaters.

Glenn F.

Veal barns probably are not as well sealed as your garage, be sure to provide some ventilation so that it doesn't kill you. And don't forget that in an attached garage, it can seep the CO into the whole house and kill everybody there too.

Be careful.