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[hrc200x]

Is infloor heat in a garage more efficient than other heating options? Thinking of building a work shop for automotive type work and wondering if my boiler could keep up, currently its heating a older house that I plan to insulate better located in northern minnesota. What temp water should be run through the slab? Heat is coming from below so maybe the thermostat could be kept around 55? Seems like we don't get -30 degrees anymore. The past couple years, on the coldest nights it has a good amount of coals left over come morning, using birch that was almost at the end of its life span.

[aarmga]

In floor heat is by far more efficient than any type of forced air, no doubt about it.

[mlappin]

In floor heat is very efficient if the slab is insulated correctly. One drawback, you can’t change temperatures quickly. We’ve discussed tearing the entire shop floor out and starting over to goto radiant slab, however unless we had a full time mechanic it may be weeks at a time when we don’t spend more than an hour in the shop every day. I don’t like to be bundled up when pulling wrenches, when I’m gonna work I turn the heat up to 65 or so and work in shirt sleeves, would take a long time to raise it from the 45 I keep it at night to 65 with a slab.

The water circulating thru the floor shouldn’t be any warmer than required to maintain your preferred air temp. I have a friend who has a radiant slab in his new shop, temp is set way too warm as on a call for heat my feet will be soaked in ten minutes as the floor gets that warm.

[E Yoder]

We run into the infloor problem down here in VA a lot. In our warmer climate people want to heat only when they are working in the shop and let it cool down otherwise to save wood. A blower can raise temperature in minutes. Infloor takes a day or two.
So in that situation (occasional heat) infloor burns more wood, but in a continuously heated building the opposite is true.. I always ask how they intend to use the building before we tackle an infloor job.

And I agree, most infloor is run with too high temp of water. It heats up quicker but over runs on warm days and sweats your feet. Should have an outdoor reset control to adjust water temps with the weather.

[mlappin]

We run into the infloor problem down here in VA a lot. In our warmer climate people want to heat only when they are working in the shop and let it cool down otherwise to save wood. A blower can raise temperature in minutes. Infloor takes a day or two.
So in that situation (occasional heat) infloor burns more wood, but in a continuously heated building the opposite is true.. I always ask how they intend to use the building before we tackle an infloor job

Exactly, like I said, if we had a full time employee that was in the shop all winter, then yes, we’d goto radiant in a heart beat, but in my current situation I run three forced air HX’s, two 50,000 BTU and a 100,000 BTU, can raise the shop temp from 45 to 65-67 in no time at all.

[E Yoder]

You're absolutely right. I know a dealer who also does emergency repairs on snow plows in the winter. He loves his infloor radiant! Dry floors.
But there's nothing like a blower for a lot of quick heat.

[BIG AL]

I have pondered this question several times when Thinking of building a new 30 x 50 shop. I am leaning towards the 150,000 btu hanging heater though , as we wouldn't be in there all the time. My 50,000 btu heater in my basement doesn't really add to my wood consumption when it runs. I feel like for the amount of time I would be in the garage I cant see heating it all the time. I would leave the pump running all the time and the t-stat low and turn it up when I was working in there. Couple ceiling fans and we'd be good to go. My 2 cents in my situation.

On the other hand I would put radiant in my bathroom under the tile floor , nothing like warm tiles.

[hoardac]

BIG AL you could always just radiant a small area so you can have a nice dry warm floor if you have to roll around on the ground and get under stuff. One or two 300 foot chunks of 1/2 pex plus your radiator you would have all the heat you could want. Leave the in-floor off unless you know your gonna need, it will take 8 to 12 hours to heat up the concrete . I have radiant floor throughout the house and it is amazing and very easy to install. Then your floor is dry when the snow melts off the vehicles in just a quick bit.

[aarmga]

BIG AL you could always just radiant a small area so you can have a nice dry warm floor if you have to roll around on the ground and get under stuff. One or two 300 foot chunks of 1/2 pex plus your radiator you would have all the heat you could want. Leave the in-floor off unless you know your gonna need, it will take 8 to 12 hours to heat up the concrete . I have radiant floor throughout the house and it is amazing and very easy to install. Then your floor is dry when the snow melts off the vehicles in just a quick bit.

You know what, this is absolutely excellent advise. I will be building our new garage this summer and that is my plan as well.  Going to build a 4 place garage 28x36 with 2 doors.  Going to heat only half the garage in floor and keep it warm enough to sustain a 40 to 45 degree temperature.  Will use forced air to heat the garage up to a comfortable working temperature when needed.  This way the in floor will never need to change and will also support forced air heat by only having to heat from 45 to 65 instead of 0 to 65.