Magdaddy

doing a stand alone propane system was certainly cheaper up front. The modine Hot dawg 30K unit uses about 1/3-1/2 gallon of propane per hour-according to Modine. That kinda consumption equates to almost $1 per hour of operation, compared to about 15 cents per hour for NG. The NG line cost me over $200 to install. Over the life of the operation, i MIGHT recover that cost.

However, the real deciding factor was how to hide the tank outside. I simply wouldn't leave it standing in the back corner without building something around it. So, by the time I built a box around it-matched the cedar shakes/architectural roofing/etc...I just shot thru the $$ savings.

I still think propane will be expensive for all season long use, season...after season. No worries about the pipes freezing either...you could always have the water circulating constantly...and only have the thermostat work the fans. Or, simply insulate the pipes, hell...heat trace them if you want. But if the entire reason is to heat the garage...then freezing should not be an issue.

ltc

For me it was easy...no NG, so propane was it.

IXLR8

Some have mentioned the Mr. Heater units which I was going to go with.

Then someone pointed me to a Cozy Direct Vent Furnace.

Any comments on the Cozy? I certainly like the simple through-the-wall exhaust installation.

matt777

You might want to compare cfm ratings on the fans. I have both the Modine Hot Dawg in my garage (similar to Mr Heater) and a Williams heater (similar to the the Cozy Direct) in my wife's art studio (old attached garage). The Modine garage style heater blows much more air for bigger areas and more circulation.

IXLR8

The Cozy works on convection I believe and has an optional blower available.

johnsjmc

Also note the gas code in Canada requires the heater to be mounted 8 ft above the floor in a garage because of the chance of gasoline fumes being ignited by it.Also so called ventfree(unvented) heaters are not legal here. There is a horizontal vent kit available for the Mr heater but I went up through the roof because the walls are brick.

IXLR8

Is the burning process not external to the heater due to the use of a heat exchanger? Furthermore, would the arc from a wall switch not ignite fumes as well?

What else does the gas code state? Can we use copper pipe just as the gas fired fireplace is plumbed? I'd also like to have a main shut-off valve in the garage, as well as some kind of conduit for the gas pipe.

johnsjmc

You can use soft copper tube just like a gas fireplace or water heater.I put a shutoff valve at the furnace where I tapped in the new line and I put a second shutoff in the garage at the heater. Use at least 5/8 copper tube or 1/2" black iron pipe. The burner is a mid efficiency design (80%) and uses room air for combustion unlike a high efficiency furnace which pipes in outside air for combustion. I think the electrical code requires vapour tight lamps and switches in a body shop spray booth but they are not required in a residential garage . I placed the wall sockets and switches above 3 1/2 ft. as a precaution but I don,t know the electrical code requirement if any. I came across the 8 ft gas code caution statement for Canada in the installation manual for the heater

IXLR8

That is news to me. I guess that is why the Modine has an air inlet as well, if you get that series (they have two series of models in the Hot Dawg range)

johnsjmc

The Mr Heater is very similar to the Modine HD series which uses room air for combustion . The Modine HDS uses seperated combustion . Most garage commercial heaters are of the room air type.It,s not usually a problem using room air just mount it high enough, I suspect but don,t know for sure that the gas code doesn,t differentiate between styles of burners. It probably requires the same mounting height for any burner in a garage. Obviously the seperated combustion style would be a better choice in a harsh envirnment. Even better would be the radient tube style heaters because they are cheaper to operate in a drafty garage. I am more than satisfied with the inexpensive Mr Heater system I have installed. After all it,s only a residential garage and since I retired I only work a few hours at a time in the garage anyway. The 45000 btu heater has an output of about 34000. It heats my 500 sf garage beautifully.