Slab heat in shops and garages.

[Vicegrip]

Why the push for slab heat in garages and shops? This is not a snarky post but a real question. I am sure there are reasons I am not thinking of. I have been wondering why they are getting popular in shops and garages. There are lots of systems going in so there has to be reasons for them. Warm floor in the house for kids and bare feet I can see but there seem to be down sides to the use in garages. Thinking about the pros and cons.

Pros, no ducts taking up space, no air blowing around.

Cons.
High initial cost.

Slab heat is super slow to change the room temp. You can't set turn the heat when you are working in the shop for a couple of hours then seat back to 45 when unoccupied. Shops and garages are taking a 24 hour time line more often unoccupied than in use. Is the loss of fast heat up and no cooling a negative aspect?

Unlike air heat a much larger amount or energy is lost to the ground regardless of insulation used. You still loose heat through the walls and ceiling but add more through the floor in as well.

Heat only. What is less good about using a single system that can fast heat maintain a low background heat and have cooling as well?

In ground tubing to worry about. Slab cracks or drilled holes can rupture it and it is hard to find and fix many leaks.

Again not a sideswipe a real question.

 

[aerobb]

Most of the time I spend on my back under a vehicle. heated slab makes it more comfortable. Also Radiant heats the objects, not the air of the building. As you stated takes a while to heat, and cool, therefore there isn't such a loss when you open that big garage door. Mine will be shut down in the summer and then only on late fall thru early spring.

 

[PAToyota]

A lot of it does depend on how you are going to use it. If you only want heat on the odd evening or weekend here and there, I would advise against radiant heat for the reasons that you cite, VG. But as Aero says, if you're going to be in there often enough you get the benefits of thermal mass - especially when you open up something like a garage door and all that warm air escapes.

I'm actually starting to look into the possibilities of a solar panel system to supplement the heat. I figure that I can likely circulate during the day and build up enough heat to keep it about 50~55 degrees minimum. Another project on the list...

 

[HoosierBuddy]

Pros, no ducts taking up space, no air blowing around.

True...unless you want a/c in the garage too. Then you end up with the duct work anyway.

Cons.
High initial cost.

Compared to what? The price of the garage? No. My in floor heating system cost less than 5% of the garage.

Slab heat is super slow to change the room temp. You can't set turn the heat when you are working in the shop for a couple of hours then seat back to 45 when unoccupied. Shops and garages are taking a 24 hour time line more often unoccupied than in use. Is the loss of fast heat up and no cooling a negative aspect?

Actually, I can heat my garage up about 10 degrees per hour. I normally keep the heat at 50 but will set it up to 60 if I'm going to work out there. It's not nearly as much of a bother as you might think.

Unlike air heat a much larger amount or energy is lost to the ground regardless of insulation used. You still loose heat through the walls and ceiling but add more through the floor in as well.

I've never seen anything that supports that assertion. In fact, since virtually all non-in slab heated buildings don't have any insulation at all under the slab, I'd argue that your garage will actually have LESS heat loss, not more.

Radiant in floor heat is just the berries. It's (by far) more comfortable because you don't have air blowing around. It's (by far) quieter for the same reason. It works fantastic in a garage where you have doors opening and closing, because you don't have any positive pressure or air movement going on that will tend to cause your heated air to go through an open doorway. Even if the door is open, you are standing on a large warm slab that is radiating heat to you, causing you to feel comfortable.

In ground tubing to worry about. Slab cracks or drilled holes can rupture it and it is hard to find and fix many leaks.

Again, this just isn't a problem if the system is installed correctly. Even if a single loop would leak, there are enough redundant loops to just eliminate that loop above the floor level, and use the rest of them.

Hydronic is a superior heat source. It costs more. If you want a/c, you still have to have ductwork, an air handler, and a compressor...so it is more expensive. The point? It'd be cheaper not to have a garage. You can just park in the driveway. If you do have a garage, it'd be cheaper NOT to heat it at all. You can park in the cold. There's always a cheaper way to go. If you've got the cash, you won't find a better way to go than hydronic.

Here's a great site:

www.healthyheating.com

Phil

 

[Franz©]

Mostly it's because of the availability of PEX tubing. People have been trying to heat sidewalks for years, and until PEX the only available fluid system was welded steel, and that had a fairly limited life.

Once a product like PEX becomes available, new aplications keep getting found to use it in.

 

[kbs2244]

You have the pros and cons pretty well worked out. I have worked in buildings with it and it is comfortable.
But I went with overhead radient. Pretty much the same advantages and a whole lot easier to work on if something goes wrong.
I figured it would be a lot easier to climb a ladder then to chop out 4 inchs of concrete.
I did do a good under and around the slab insulation job.

 

[Steve in Mi]

Where you are located plus how you use your garage can have a big effect on the system you select. I insulated my shop as if I was going to use in floor heat but at the last minute changed to GFA heating for quick recovery as I wasn't sure how much I would use my shop (time constraints). That was in 1981. BTW, soft copper in floor heating systems were being used here in Midland, Mi. from the late 50's that I'm aware of. Anyway, getting back to the effect of area (location), my shop insulation is such that the warmest it gets in my shop in the Summer is 72 -73 for a very brief period (a week or two) so I don't feel the need for A/C. I do keep it closed up as much as possible - no open doors to show off the contents. I open a door to move equipment in and out but then shut the door ASAP. Hey when it is 85 degrees outside why let outside air heat up my cool 65 degree shop? In the 6 months of Winter I heat 24/7 to 63 - 65 degrees which I find a comfortable temperature to work at. So my temp swing year around is 63 to 73, I like it. What I like even better is that it cost very little to maintain this in my 28' X 48' two story shop (picture to the left). In 1999 when I started heating steady throughout the Winter I estimated my NG heat at $90.00 for the year, last year that estimate was $140.00 due mostly to constantly increasing gas cost. I know some that would be happy to heat their shop for one month for $140.00 and they are smaller shops. I chalk it up to my great design, tightly sealed well insulated space put together stick by stick with TLC by yours truly.

 

[tigmusky]

in floor heat the best!! I did my shop with pex about 5 years ago and love it! garage doors never freeze shut . I keep it 68 degrees all winter thats at the floor 6' and 12' the ceiling. it's 68 degrees floor,ceiling and cornors. pull a snow covered truck in, lose no heat. snow melts off and, the floor is dry in 4 to 5 hours no sweaty tool or windows. if I had to do over i do it in a heatbeat, but next time i would used a boiler instead of a hot water heater. daye

 

[chevelle64]

What is your reasoning for a boiler instead of a water heater
Just curious. Thanks

 

[tigmusky]

72vette454 ,A boiler has no storage tank, it heats only when needed being more efficient and a lot smaller in size...... more room for tools. with a water heater like mine it's heating 80 gals of water all the time. even if the shop does'nt call heat in 2 days. Also biolers have faster recovery time. hope this helps, merry x-mas daye

 

[Steve in Mi]

72vette454 ,A boiler has no storage tank, it heats only when needed being more efficient and a lot smaller in size...... more room for tools. with a water heater like mine it's heating 80 gals of water all the time. even if the shop does'nt call heat in 2 days. Also biolers have faster recovery time. hope this helps, merry x-mas daye

Some boilers don't have a storage tank just as some water heaters don't. Paloma comes to mind. http://www.palomatankless.com/

As long as the heated water is in the space it is to heat, namely the garage, little if any efficiency is lost. As far as recovery time goes, they are both rated in BTU's per hour so you match your requirements to the unit you purchase - you get what you spec.

 

[rsanter]

you can also use solar hydronic to do preheating during the day. if you have a black lined box covered with lexan cover and have black plastic pipe running back and forth inside. all you would have to run is a small pump to move the fluid. orient the box to collect the mid day sun. you can run a parallel system or three way valves into the main system. even in snow country you would be suprised how much solar heat you can collect.

bob

 

[tigmusky]

As long as the heated water is in the space it is to heat, namely the garage, little if any efficiency is lost. As far as recovery time goes, they are both rated in BTU's per hour so you match your requirements to the unit you purchase - you get what you spec.[/QUOTE]

yes, you are right .. a boiler will hold and mantian high water temps becuase of the less volume 80 gals.and increase reponds time even if the btu are the same. daye

 

[Maulerman]

Steve in MI made a good point in slab insulation. Edge insulation in critical to reducing heat loss with slab heat.