Garage heat

[Dave in MN]

Originally Posted by mnguy

OK northern Ford Barners. Looking for advice on heating a 1200 sq ft garage area in Minnesota. Area is attached to house and has one single and one double overhead door. Walls and ceiling are still open. Gas or electric heat? Not considering wood heat. Let me know heater brand names if you are so inclined. Thanks in advance for sharing your advice and experiences.

mnguy,

I have been a Minnesota Home Builder/General Contractor for 44 years. I have seen just about every type of heat people put in their garages, some are good others lead to trouble.

First: You say the garage is a typical three car attached but yet un-insulated. Get the needed wiring, gas-line and heater venting installed and inspected before placing any insulation or cover material. Insulate the walls and ceilings, cover the entire ceiling and wall areas with the proper fire-rated drywall to conform with your municipalities code. Stop to see the Building Inspector and ask for his advice. Yes, get the heater installation and wiring inspected, your family's safety depends on it.

Second: Since this is an attached garage, you are likely using it to park your daily driven cars. You know Minnesota winter roads and the stuff you bring into your garage each time you arrive home. All the accumulated snow, ice and salt will melt from your car each evening and fall to the floor. In a heated garage, this water will quickly evaporate and load your garage with moisture. The best way to vent this moisture from the space is to install a ceiling hung gas fired space heater. The space heater should be designed to draw its combustion air from the garage space and in doing so will pass the damp air through the combustion chamber and move it to the outside. You do not need to install a make-up air duct, the seals around two overhead garage doors will allow enough make-up air in. The air coming in around the overhead doors will be cold and dry (cold air can not hold much moisture) the air being cold will sweep across the floor and dry the surface. It is best to install the heater away from the garage doors so you encourage the air circulation to increase the sweeping effect to dry the floor. Warm air is directed towards the overhead doors across the ceiling, gets to the cold doors then cools and drops to the floor it is then drawn back towards the heater and in doing so contributes to drying the floor.

Third: Since you have a desire to have a heated attached garage, please install a carbon monoxide sensor to keep you and your family safe. There are no short cuts on safety.

Equipment: Invest in a Modine Hawt Dog ceiling mounted heater. Compact and safe. No open flame! (They are often on sale at your local Fleet Farm.) Get about a 60,000 BTU unit. This suggested unit is slightly larger than the space needs but if you only heat the space when you want to work, the unit will bring the temp up quicker. Picture this: Arrive home from work and turn up the stat as you enter the home, grab something to eat and go back to the garage 15 -20 minutes later and it will be warm. Install a wall mounted thermostat located on the common wall to the house away from the heater; next to the entry door to the house is always convenient. Face the heat output from the heater towards the overhead doors.

Note:
There would be more options for a good heat source if you were heating a shop space where you did not bring lots of moisture in each day from daily driven cars. Closed loop heaters and ceiling mounted radiant heaters work well in a dryer shop application as well as some off-peak electric heaters and in-floor heat loops.

Long winded...I know; but proper heat in Minnesota is important!
PM me if you want a phone number to ask more questions. I am not looking for work...Just offering some sage advice.
Good Day!

[bills]

Great information! Thank you!!

[Ed Saniewski]

Dave in MN, do you find many people installing radiant floor heat in their homes and garages?

[Dave in MN]

Originally Posted by Ed Saniewski

Dave in MN, do you find many people installing radiant floor heat in their homes and garages?

Ed,
In the homes (living space), yes quite frequently with good results.
In the attached garage...Not on my jobs! (I repeat to them what my previous post contained.)

In Minnesota some do use it in their garages but I usually don't see the installation until 3 years after they move in when they call me to complain about the mold growing on the sheetrock in the garage. At that point, we treat the walls with an anti-mold product and install an exhaust fan wired to a humidistat. I warn them that even with the exhaust fan, the mold will eventually be back.

The warm floor converts the melted snow to vapor so fast it moves into the cooler drywall before any amount of venting can move it outside.

Good Day!