Shop Heat - Why Didin't I think of This sooner?

[Bruce Wrenn]

I have a ventless, wall mounted gas heater in my shop. Located on the ceiling, near the heater is my air cleaner. Last week, I had a BRILLIANT IDEA! Why not add a line voltage thermostat to air cleaner so when heater comes on, air cleaner also comes on, circulating warmth through out the whole shop. Works great! Thermostat has to have a "cooling function." Meaning when temperature rises, contacts close, and open on fall. I had a remote bulb thermostat on hand, so that's what I used. Thermostat is mounted on wall, and sensing bulb is above heater on ceiling.

[Bill Dufour]

A ventless heater is a poor idea in occupied spaces and especially in a woodshop. They are not legal in my state for a good reason. Make sure you have a working CO alarm if you use one.
They put out about the same weight of water as the weight of fuel burned. So the humidity in the shop is all over the place. Hot and wet then cold and the water condenses everywhere.
Bill D

[Bruce Wrenn]

Bill, you have to remember that you live in another world. (CA) We can't send an OTR truck into CA that is older than 2007, but it's legal in the other 49 states. My shop is in a separate structure, and I have NEVER had rust or condensation problems since adding gas heater. A CO alarm is REQUIRED anywhere you have a fossil fuel, or wood burning device. As for hot then cold, I maintain my shop at 55 degrees from Nov 1 thru April 1, so there is no temperature swings to form condensation on surfaces. They are all above the dew point all the time.

[Bill Dufour]

I do know that gas cooking stoves used to be vented with a flue pipe for the oven but that is no longer an option, even here in California. The top burners were never vented at all.
I remember when it used to be a common thing to read about a southeast Asian family using a hibachi grill to warm the house at night. They would be found in the morning all dead of CO poisoning.
Bill D

[Bill Dufour]

Your fan idea sounds like a good idea to me. On my woodstove I added four computer case fans run off a doorbell transformer with a thermostat that senses when the stove gets hot. I added a big capacitor so there was enough amps to get them all running at once after I dialed down the running voltage to reduce noise. When running they are supplied with about 11 volts through a variable resistor.
And in Crazy California when I sell the house I will have to either remove or permanently block the stove shut.
Bill D

[Jim Becker]

Using the air cleaner to provide additional air circulation is a very good idea and a nice use of something that's already there. I'd like to try that in my shop, but unfortunately, my air cleaner faces "toward" my heat source because of how my shop is arranged and where I machine and finish. It would certainly make my heating arrangement more efficient, however, and I may consider leveraging a simple fan to perform a similar function...I do that already with my small AC unit which is at the opposite end of the shop.

[Bill Dufour]

Using the air cleaner to provide additional air circulation is a very good idea and a nice use of something that's already there. I'd like to try that in my shop, but unfortunately, my air cleaner faces "toward" my heat source because of how my shop is arranged and where I machine and finish. It would certainly make my heating arrangement more efficient, however, and I may consider leveraging a simple fan to perform a similar function...I do that already with my small AC unit which is at the opposite end of the shop.

I suppose you could have a "door" or roller shade that swings down from the ceiling to bounce the airflow around in winter ? Maybe a magnetic catch to hold it open/closed. In my last shop I had a hinged door to close off the roof vent in winter.
Bill D

[Bruce Wrenn]

I remember when it used to be a common thing to read about a southeast Asian family using a hibachi grill to warm the house at night. They would be found in the morning all dead of CO poisoning.
Bill D

Burning charcoal gives off CO due to incomplete combustion. Modern gas heaters emit very little CO. They all have oxygen depletion sensor (required) which will shut them down. Last night's low was 29, and today's high was only 39, which is about 15 degrees colder than normal. Shop temp only varied by two degrees (55-57) and relative humidity reached max of 46%. Before adding heat, when we had a day like last Saturday (70+) every metal surface in shop would have condensation if I opened the doors any.

[Jay Larson]

I have a little electric heater mounted on the ceiling. I have found out that if I run the dust collector at the same time as my heater, it gets the shop warmer. At least down where I am working. Otherwise the warm air stays on the ceiling. I have tried pointing the vents down, but then I get hot air blowing on my neck when I am at the table saw.

I do have plans to put an air cleaner on the 'other' side of the ceiling. When I get to building one in the next couple of months.