Adding Heat to Garage?

DJDrew

We have a 1938 small garage that is below living space, the garage is too small for 2022 vehicles, so I use it more as a workshop. The living space above is OK, but the floor is always cool. We are replacing the garage door with an insulated model. Would adding a panel radiator with a TRV set at 63 degrees help keep the garage and the room above more comfortable?

The garage itself has concrete floors and block walls, the room above is insulated. Would adding an insulated garage door and radiator make much of a difference, or is it a lost cause with the concrete floor and block wall?

Adding an additional radiator into the system seems feasible, as there is a supply/return piping highway circling the house and all the radiators have individual connections to that piping, so it is easy to add another tap.

Thoughts?

Paul Pollets

Oversize the panel rad to account for the uninsulated slab. The insulated garage door will help reduce the heat loss

Big Ed_4

Add a venturi tee to the return riser . If possible run the two risers up hill all the way . If not add a set of purge valves to the riser to remove air from the risers .Add the optional radiator diverter when using theTRV not to take away from the rest of the system..

pedmec

Is your garage above or below grade?

DJDrew

Thank you for the help, those are good ideas!

pedmec said:

Is your garage above or below grade?

It is mostly below grade.

mattmia2

You have separate supply and return mains, right, this isn't a monoflow system?

Adding some foam insulation and drywall over the block would help a whole lot.

pecmsg

Nothing will warm that slab comfortably except in floor radiant and slab insulation. 

mattmia2

pecmsg said:

Nothing will warm that slab comfortably except in floor radiant and slab insulation. 

Of course if you aren't planning to use it as a garage you could do sleepers, foam, and plywood.

DJDrew

mattmia2 said:

You have separate supply and return mains, right, this isn't a monoflow system?

Correct, separate supply/return mains.

pecmsg said:

Nothing will warm that slab comfortably except in floor radiant and slab insulation. 

That sounds like an excessive amount of work, but would be really cool. I just want to make the place tolerable in the winter when I am working and hopefully the floor in the room above a little more comfortable.

hot_rod

Radiant on the ceiling is second to floor radiant for comfort. Much easier to install.
Some tube and transfer plates is all you need. Very quick responding, even works with setback stats. Radiant energy travels at the speed of light, the second the tube and plate warms you feel that energy.

Use copper tube and leave it exposed even Pex would need to be covered for UV protection.

I thought about using a thin wall steel tube, like electrical EMT conduit, if you could come up with a good connection.

Great for melting snow from vehicles.

bburd

I would be cautious about installing a hot water radiator near the floor of a garage, due to the danger of freezing in a power failure. You could install it high on the wall if your only concern is making the room above more comfortable, which would make it a bit safer from freezing;  but that won’t do much for your workshop.

DJDrew

bburd said:

I would be cautious about installing a hot water radiator near the floor of a garage, due to the danger of freezing in a power failure. You could install it high on the wall if your only concern is making the room above more comfortable, which would make it a bit safer from freezing;  but that won’t do much for your workshop.

I agree about keeping this off the floor. I was thinking of a panel rad that is about 20"x56" mounted fairly high on the wall. However, you and @hot_rod make me wonder if I should do something on the ceiling instead. I know one neighbor has exposed baseboard elements running all over his ceiling, I wonder if that would be better than the panel radiator.

Big Ed_4

Exposed convertor elements no , Radiant ceiling would be nice ... A radiator is part convection and part radiant heat . In a garage I instal them part way up the wall ...

bburd

DJDrew said:

I would be cautious about installing a hot water radiator near the floor of a garage, due to the danger of freezing in a power failure. You could install it high on the wall if your only concern is making the room above more comfortable, which would make it a bit safer from freezing;  but that won’t do much for your workshop.

I agree about keeping this off the floor. I was thinking of a panel rad that is about 20"x56" mounted fairly high on the wall. However, you and @hot_rod make me wonder if I should do something on the ceiling instead. I know one neighbor has exposed baseboard elements running all over his ceiling, I wonder if that would be better than the panel radiator.

I would put a panel rad on the ceiling above the workbench, a simple panel without extended heating surface fins. That will maximize radiant heat transfer to your work area. You will get limited convective heat transfer from a ceiling mounted radiator, helping to warm the room above, as well as comfort while working down there and decent protection from freezing.

High on the wall would work as well.

hot_rod

I guess it depends on how much heat you want. A panel rad by the bench would warm YOU when you are working, probably not the entire garage.

I did a body shop years ago with copper tube in ThermoFins screwed to the ceiling.

The owner loved it, no dust blowing around, no noise like the unit heater he had previously.


It's a surface area game with any radiant emitter, the larger the area the better the output and lower the required SWT.

Some panel rads have both radiant and convection output if they are finned between the sections.

If you ran a heatload calc on the garage you could get an exact number on what is needed to maintain a desired temperature.

Garage door insulation and good weatherstrip on the door are a must.