Radiant Heat or Not

[Grizzlyman]

I am in the process of building a house and attached garage. I am in Western NC and the winters are not very cold. The average winter months are a in the low 40's. My shop will be 36 x 40 with 10' ceiling. The overhead insulation will be R38 plus and R21 in 2x6 walls. I am using a 2.5 ton mini split HVAC system for primary heating and cooling. I will be installing 2" foam board insulation under the concrete slab. The slab will be 4”-6” thick. I was thinking about installing 1/2" PEX for radiant heat to help warm the concrete floor during the winter months. The radiant floor will not be the primary heat source rather warm up the floor for better working conditions. I would be heating the water with solar panels on the garage roof. In my last shop, the floor would get cold and very uncomfortable if I was on a creeper or working close to the floor. I did not continually head my last shop as I will this new garage. I only heated it during the weekends when I would play with the hot rods. I did not have insulation under the floor in my last shop. Anyway I am looking for advice on this topic.

 

[HoosierBuddy]

I would say "no".

If you have available solar heating capacity (or cubic **** loads of cash to outlay for same) you'd want to use it to effectively heat your primary residence, rather than use it for a part-time/non-essential application.

IIWY, I'd go with the mini-split and call it good.

Phil

 

[bobsgarage]

Ten years ago I built a standalone garage in West SC, in which the construction is very similar to the one you are building. It is 51 x 31 with a 12 ft. ceiling. R40 in ceiling R21 in 2x6 walls, exterior is brick with three insulated overhead doors and insulated pedestrian doors. Bath with shower. Gas central heat, water and 3 ton a/c, all duct work in the conditioned space. I keep the Winter temp. at 60, Summer temp. at 80, bump it up or down when working there. Winter Gas/electric about $75, Summer Gas/electric about $85.00. Because of the second gas and electric meters must pay commercial rates. I thought about heating the floor, but opted for a two post lift. With the lift I do not have to lie on the cold concrete floor work on cars, therefore heated floor not required. Have fun with new garage.

 

[Mr onetwo]

At least put the blueboard under the slab and put in the PEX to your manifolds.PEX is cheap and easy to lay out.That way you can do anything you want later.It will also increase your resale value.

 

[Grizzlyman]

Thanks for the info. I am decently going to put 2" of insulation board under the concrete. The insulation board cost more than the PEX and manifolds. I was surprised at the cost of foam board.

 

[Mr onetwo]

Yup...up here in Maine it has doubled in price in the last 12 months!

 

[Steve in Mi]

Grizzlyman, your plan for insulating sounds good as far as you go with it but there I no mention of how you will prevent heat loss from the 4" to 6" thick slab around the perimeter. With what you plan for the rest of the structure the slab edge (including drive aprons and door sill extensions not isolated from the slab by a thermal barrier) heat loss becomes the biggest hole in the boat, if you get my drift.