So I was looking for a heater for the garage at the new house I bought and I had a question for the masses. I see these non vented 99.99% efficient propane heaters etc going cheap but how good are they?? Do you still get that propane smell? Are they safe for working around? I would be working in the new garage quite a bit and don't want to get the black lung!!

Here is the link of an example
http://www.northerntool.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=6970&productId=1029784&R=1029784

The idea behind those things is that they totally consume all the LP - thus no smoke - no fumes. I know a lot of people up nort' that run those babies in their family rooms and porches to add extra heat. They work good. The main drawback is no fan. I'd rig up a couple of small fans to help circulate the heat - slow speed is best - don't need to cool everything down - just gently circulate. (I used to use computer case fans in the corners of my doorways to move air from room to room when I heated with wood - they worked great - less than 2* drop from one end of the house to the other and you can't even hear them run.)

so what if they burn 99.99% of the propain.

what about the gases they leave behind?????

as in carbon monoxide, carbon dioxide, both will kill you and you can not smell them.

so you must keep a window open....sorta makes having the burner on a moot point????

Those type of burners are much like the catalytic heaters that are used in tents... They burn their own gasses.

They DO consume the oxygen in a room - but in a garage-sized area, and with the typical sealing arrangement of most workshops - you would be fine.

Ahhh I see now, I was doing some reading and apparently the moisture output on those puppies is kinda high and they recommend a large dehumidifier in the room as well.

The space is 24x24 with a 12' ceiling so I figure I need about 15000 BTU at the very least (I think) so this unit would do nicely if I had the fans to push it around. The local HD has ceiling fans on sale right now for $25 so I would think two would move the hot air out of the high spots and create circulation.

I guess a CO detector is a good idea to eh?

Anyone else with input?

I have a 20,000 BTU unit in my 22x24 garage, and it works great. As long as you are not air tight, you will be fine as far as oxygen goes. No smell or anything from the one I have. It also has a built in fan in mine too. Yes, they do release moisture in the air, and your tools can rust if you are not careful.

I have a 24x28x12 garage with R20/R40 insulation and 1 heated wall, I use one of these to heat it:

http://images.canadiantire.ca/media/images/AroundtheHouse/Electrical/HeatersFans/0522604_450_CC_361ad.jpg

Puts out ~16,000 BTU's, has a built in thermostat and fan for $80 at your local crappy tire.

No worries about flammable gas in the garage, no problems with Carbon Monoxide or humidity as well as cheaper to buy and likely cheaper to run.

If you are planning on running a small heater off of a 20# propane cylinder the electric heater can be cheaper to run. A 20# cylinder of propane is ~ 440,000 BTU and costs me $10 to refill so it costs 2.3 cents/Thousand BTU. 1 kilowatt-hr is ~3400 BTU and costs ~6 cents so 1.8 cents/Thousand BTU.

MATH!!! aghhh my eyes are bleeding....

Problem with my space is its got no heated walls (stand alone) and one of those 18' long single metal doors on the front and that would be a bastard to seal up nice and tight.

How long does it take your garage to heat up from dead cold with that heater?? I just finished rebuilding the house so the garage is next and I could wire the plugs into the service I am designing.....

The thing that must be remembered when burning hydrocarbons is that they produce almost as much water vapor as fuel burned...the electric heater that was pictured above works well....and is much better in a metal building like my shop as there is little condensation,

Agreed, I am in a stick and panel building which looks to be about 15 years old maybe more (still trying to find out) Its got insulation but the older tarpaper backed stuff and the wood panel on the walls...

I am going to pull the panelling and reinsulate, vapour barrier, tuck tape and drywall the whole thing but I wanted some heat to do it with, -15 is chilly and thats been the daytime temps lately.

I'll go whatever makes more sense, if electric is better i'll do it but I don't want to wait 2 hours for it to heat up enough for use.....a wood stove gives better performance than that.

CRO how big is your building? How long does it take to heat up with electric??

I mainly use it to keep the garage just above freezing, if it is -20 outside and I want to putter in the garage if I turn up the thermostat about 3 hours ahead of time it is about +12 to +15 when I go out (from just above freezing). If I am in a hurry I just use a tiger torch to warm it up quickly, it has 2-9x8 R14 doors with decent seals if that helps you out.

Find a furnace repair dude...

Slip him a 6er of whatever he drinks...

Ask him nicely for a used house furnace...

Get one free and stick it in the garage...

Set it up about 3 feet off the floor so you don't suck up fuel vapor...

Plumb it to natural gas or an LP tank (even the 100# size - like the old mobile homes used will work)...

Hook up 120V to the controller and a 24V thermostat somewhere on a wall opposite from the furnace...

Enjoy the heat...

If you want to get fancy - you can even get a sheet of galvanized and make a plenum box over the top and run a couple of ducts to the other sides of the shop.

I scored mine today. :D

As has been mentioned, big problem with the "ventless" gas heaters is the moisture buildup. Probably more of a problem in a house than in a garage.

I second the idea of trying to find a used furnace. If not free, could probably find one very cheap. Just saw one for a mobile home in the local classifieds the other day - free if you hauled it away. I have a friend that does HVAC work. He has scored a few squirrel cage fans for me from removing old equipment. They just toss the stuff in the dumpster.

I guess I could find a LGP furnace or get a NG one converted, I cannot run the gas from the house out to the garage right now....cost and frozen ground.

I'll keep looking...

I guess I could find a LGP furnace or get a NG one converted, I cannot run the gas from the house out to the garage right now....cost and frozen ground.

I'll keep looking...

The change over from LPG to NG is typically just an orfice in the gas valve. Your local LP distrubtor would have them in stock... No big deal, I've done it a bunch of times. At the very worst, it is a replacement gas valve - still cheaper than a new ventless unit.

Here is a very basic article that explains why there is a difference.

http://home.howstuffworks.com/question197.htm

A paragraph from a gas utility site:

If your furnace is in good condition, the only change you'll need to make is to modify your gas valve in the furnace. Most new furnaces are made ready for natural gas and require a "propane kit" which costs $15 to $25. Most likely, you should be able to buy a similar kit to convert your furnace back to natural gas for a similar price. The benefits of natural gas over propane are constant, uninterrupted supply and generally the price is comparable, or less than propane. If your furnace is in a basement, natural gas is also safer — propane is heavier than air and can accumulate in the basement, causing an explosion, while natural gas is lighter than air and will rise [if you smell gas, always turn off the gas, open all windows, and leave your home and call the gas company from a neighbors house].

And, here is an actual PDF document for making the changeover on a furnace.

http://www.nordyne.com/Literature/708285b.pdf

If you look at the price to install your free furnace to meet Federal, Provincial and Municipal codes (Regulator, B-Vent, LPG Conversion kit, cylinder/tank, hoses/piping, etc) you will find that your free furnace gets pretty expensive.

If you already have 240V service to the garage installing a 240V/20A branch circuit will cost you $25 and the electric heater can always be returned to crappy tire if you are not happy with it's performance.

I have a 18k btu ventless LP unit and with a semi attached (1.5 walls) garage thats 20x22, it works great. I ditched the Keroseen heater due to the fumes, this has the O2 depletion sensor to shut it self off if needed etc.. Its also my backup house heater if needed.. The Pro somthing unit i have from northern has a fan kit but i use a small box fan on a shelf.