Hydronic garage heat options

Mosherd1

We’re in the middle of remodeling my mothers split level home.  We’re adding radiant floor heat to the main living/dining level, and the upstairs bedroom/bathroom level, and hwbb to the basement sized to use the same temp water as the radiant floors. The 24x24 garage is underneath the bedroom/bathroom level. Since we’re installing a condensing boiler for the rest of the house I would like to use it to heat the garage as well. I see 4) options and would like everyone’s thoughts. 1) I can fit about 70 feet of hwbb out there, but I’m not sure how good of an option that is, part of the garage will be used for storage and I’m concerned stuff will get in front of it, 2) install two toe kick heaters, 3) install one larger hydronic fan coil, 4) install radiant ceiling. This is my first choice but everything I read says not to install radiant ceilings over an uninsulated slab. The concrete walls are going to be studed up and fully insulated, as well as the ceiling above, but I can’t do much with the existing slab insulation wise.  Am I missing any options? What are your guys preferences?  I would love to jack hammer out the existing slab, insulate it, and repour it with infloor tubing, but that’s not in the cards right now. 

Intplm.

Have you looked into "Modine Heaters"?
This might be a good fit.

hot_rod

Are you going to be working in the shop, or mainly storage?
For a comfortable working shop, the ceiling radiant is second to floor radiant. Easy to install, clean, quiet, doesn’t encumber the space, low SWT for condensing operation. Could be used for some cooling also.

For vehicle and tool storage a hydronic unit heater is quick and easy. Not as nice to work under, imo.

Mosherd1

@Intplm. yeah, they are overkill for this garage, I only need about 15,000 btus to heat it.  I’m planning on installing a ventless “Blue Flame” heater only as a back up if the boiler should fail or the electricity goes out, as there is plumbing run in the garage ceiling and I don’t want any chance of it freezing. 

Intplm.

I'm not a big fan of electric heat, but Modine does offer some small electric models that might be worth a look.

Mosherd1

@hot_rod the garage is mainly used for mom to park her car in and storage.  I really like the idea of the radiant ceiling (I used it in my living room and kitchen where I couldn’t half way easily retrofit floor heat in). The only thing I worry about is, everything I read says not to use radiant ceilings over uninsulated slabs. 

hot_rod

The radiant ceiling doesn’t know or care what space it is in🤓. It heats whatever it can ‘see” in the space, line of site radiation.

The only downside in working shop is it doesn’t wam the underside of vehicles

Lack of underslab insulation just drives up the load, not unlike uninsulated walls, doors, windows, etc.

Sounds like you are just warming the space, not looking for 70F? It will lower the load for the space above also. But gas bill will increase as you heat more space.

I had radiant ceiling in my last home in the kitchen/ great room, very comfortable once I insulated the crawl space below.

Mosherd1

@hot_rod the garage will probably set most of the time in the upper 50’s-low 60’s, enough to keep the snow melted off the vehicle, and make the car somewhat comfortable to get into in the winter time.  Yes, heating a garage will raise the fuel usage, but mom is 77 today and has the means to pay for the luxury of being able to afford to keep her car comfortable in the winter. 

hot_rod

Mine was very low tech, I screwed the plates against the sheetrock used some Uponor PAP for the tube, UV protected, white in color so the misses wouldn't notice the installation

One of the ThermoFin extruders was nearby and they ran some 10' pieces for me.

I also did a body shop bay that had metal ceilings, I used ThermoFin with copper tube. The entire metal ceiling turned into a radiator!

Mad Dog_2

My vote is for a Modine HW blower unit. Fast up and perfect for garage. Mad Dog

kcopp

A Cast iron radiator. Can handle abuse. Oversized would allow it to condense w the new boiler. Im sure you could find a used one for short cash.

Jells

I installed a K120 kickspace in the joists to heat my leaky 1000 ft basement, works like a charm! Sure is cheap and easy enough to try. I used 3/4 PEX, and a large port Schneider zone valve for the most GPM.

Lance

We live on the floor. HEAT the FLOOR. Of course, if it's expensive, whatever will work until you spend enough money and then say, I wish I heated the floor. Garages do not need to be warmer than 55F-60F unless you want to live in there. The mice might live there though. An auto mechanic I know used a water heater to heat his garage shop floor after 40 years and said it's the best thing he ever did.

Kirk Shriver

I would suggest electric radiant dry wall ceiling, a 4'x12'x5/8", above the spot where the car is parked. It'd be wired through a programable thermostat which would be wired through a sensor to know when a car is in the. spot. This form of radiant ceiling is very efficient, it would only be activated if a car was parked in the protected space AND the temp was below a certain level. It could be programed to begin warming your car about 2 hours before you leave for work. Perhaps you could just buy a new car with heated seats and steering wheel? Electric radiant DW is relatively cheap, very simple to work with, very cheap to add controls, and much less costly to install.