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Heating with radiators vs in slab heat.

747mopar

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I hate to even start another thread on heating but do have good reasoning at least I think. I just finished my first full winter of heating the garage with the boiler and am pleasantly surprised, kept the garage toasty warm without a single hiccup and even held the slab at 62-65 degrees all winter long.

Now it's time to put an end to the wifes never ending home renovation ideas and finish this damn garage! The first thing is concrete so I need to nail down how I'm going to heat it?? I was sold on in slab heat but my #1 concern is time... how long does it take to heat up a whole slab? How would radiators work in comparison? The addition will basically be a parking garage that will double as a paint and body shop so it's only going to be heated from time to time and I'd like the ability to be able to heat it quickly.
 
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Bruce
 
Slab heat meaning radiant heat? That type of heating is really designed for a more constant heat,not an occasional heat source. I mean it would work I would think, but heating the slab of concrete would take a good amount of time. Not to mention the chance of the liquid in the floor freezing without glycol added to it. If that is not what you are talking about then disregard anything I typed and call me a dumb F*$& hahaha! I am just confused because you said you used the slab heat but need to do concrete this year so maybe I am missing something?
 
Slab heat meaning radiant heat? That type of heating is really designed for a more constant heat,not an occasional heat source. I mean it would work I would think, but heating the slab of concrete would take a good amount of time. Not to mention the chance of the liquid in the floor freezing without glycol added to it. If that is not what you are talking about then disregard anything I typed and call me a dumb F*$& hahaha! I am just confused because you said you used the slab heat but need to do concrete this year so maybe I am missing something?
No everything your saying is exactly why I'm thinking in slab heating may not be a good option. To clear your confusion, when I said it held the slab at 62-65 degrees that's in the main garage that's finished this will be for the addition (24×24). The main garage is heated using a radiator mounted in a propane furnace and it still keeps the slab nice and comfy.

I also have to consider freezing regardless of which way I go so unless I add glycol, it at least has to be above freezing.
 
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heated floors are nice I was used to working on very cold concrete ,went over to a friend garage and its heated sure did spoil me for the day
 
heating the slab will take a while, but you say you're doing body work? With slab heat, you won't be blowing all that dust around
the shop! It's more steady, even heat, and when you're crawling around under that car you'll be glad you did it. More ecinomical
too! But, you won't go from dead cold to 62 in a half-hour. First you have to put down the 2" corning pink rigid insulation, then
install your pex tubing, then bury it in concrete. Good luck with the project!
 
No everything your saying is exactly why I'm thinking in slab heating may not be a good option. To clear your confusion, when I said it held the slab at 62-65 degrees that's in the main garage that's finished this will be for the addition (24×24). The main garage is heated using a radiator mounted in a propane furnace and it still keeps the slab nice and comfy.

I also have to consider freezing regardless of which way I go so unless I add glycol, it at least has to be above freezing.

I would honestly run the in floor heat and keep it at 50, then bump it up on a Friday afternoon to its warmer on weekends when your out working. The benefit is low dust like zyzzyx said, and your feet and legs don't get cold from soaking up the cold from the concrete. I bet you that the cost isn't that much more than forced air turning it up and down all the time. My dad has it in his 30x40 shop and he keeps it at 68 and it cost him $100 a month at most in the super cold months with natural gas. I have forced air and the cold/hot feeling sucks when the heat kicks off.
 
Radiant tube?
Cheaper than in floor. No dust from a fan on forced air. Simple install.
 
heating the slab will take a while, but you say you're doing body work? With slab heat, you won't be blowing all that dust around
the shop! It's more steady, even heat, and when you're crawling around under that car you'll be glad you did it. More ecinomical
too! But, you won't go from dead cold to 62 in a half-hour. First you have to put down the 2" corning pink rigid insulation, then
install your pex tubing, then bury it in concrete. Good luck with the project!
Yeap already looked into it and have given it a lot of thought, I'm absolutely not going with anything that moves air and it will get the 2" foam regardless of which way I choose to go.:thumbsup:
heated floors are nice I was used to working on very cold concrete ,went over to a friend garage and its heated sure did spoil me for the day
I know the feeling. The floor temps in my main garage with forced air never dropped below 62 degrees even in below zero temps with the thermostat set at 68 but it's sitting on a full foundation too which really helps... my old garage, your feet went numb! The addition is just a pole barn so I don't know that it would do as well even with the foam?
 
I would honestly run the in floor heat and keep it at 50, then bump it up on a Friday afternoon to its warmer on weekends when your out working. The benefit is low dust like zyzzyx said, and your feet and legs don't get cold from soaking up the cold from the concrete. I bet you that the cost isn't that much more than forced air turning it up and down all the time. My dad has it in his 30x40 shop and he keeps it at 68 and it cost him $100 a month at most in the super cold months with natural gas. I have forced air and the cold/hot feeling sucks when the heat kicks off.
My big issue is I may not do a car for 2-5 years, I really want to be able to shut it completely off unless I'll be working on something. I've got the main garage that's set up really nice for everything but bodywork.
 
Just some thoughts based on my experience with boilers and slab heat.

I use slab heat in my detached shop using the house boiler in my home and the house thermostat combined with a mixing valve to control the temps. A couple things I considered for faster warm-ups are keep the tubing close to the top of the concrete so you don't wait for the whole slab to heat, use an adjustable mixing valve to regulate the temp of the water up when you want to use the area you can up the temp and then down when you don't (but I wouldn't turn it all the way off myself in your case (maintain 35 degrees for those cold start days).

I built a 4 zone manifold for the shop when I did mine and if I add an addition I would use 1 of the zones from the manifold for heat. If you go radiators like I have in the house they use water at 190 degree to be efficient but you could run at a lower temp as most slab tubing was not rated for temp that high. An option to the cast iron boilers which take some time to get hot would be what they use in newer houses called "Fin Tube" (copper tubing with finned aluminum attached). That stuff should be available at any plumbing supply.

When I set my closed system up I used the pink RV solution additive incase I ever wanted to shut a section down so that runs through the house and detached garage.

Also note that my information is based on what was available 17 years ago when I installed my system and I am not in the heating or plumbing industry.
 
My big issue is I may not do a car for 2-5 years, I really want to be able to shut it completely off unless I'll be working on something. I've got the main garage that's set up really nice for everything but bodywork.

Yea we did my dads tubing about 7 years before actually actuating the system. It is one of those do it when your pouring the floor now or never situations. We ran the glycol mix with water which is good for about 35F below which will never hit that in an attached building. It is a toss up to what will cost more depending on use. The boiler and floor heat system sure costs more up front. I would do the floor heat, but let us know which way you end up going. I have the furnace hanging in the ceiling in the corner gig in my shop because it was that way when I bought it. I can see benefits to both systems like you said for sure.
 
boy do I remember in my younger days working out doors on large gravel all year round and boy it was rough in the snow ,when I was a welder in the winters out door welding in the snow was always fun on top of a coke battery in the mill or in the Army working on Track Vehicles in the snow in the field Cold BRRRRR
 
boy do I remember in my younger days working out doors on large gravel all year round and boy it was rough in the snow ,when I was a welder in the winters out door welding in the snow was always fun on top of a coke battery in the mill or in the Army working on Track Vehicles in the snow in the field Cold BRRRRR

BBBRRRRRRRRRRRRR. I'm 32 and hate the cold....I am a Sally when it comes to the cold. Hate that ****.
:lol::lol::thumbsup:
 
have slowed down some hitting the big 70 early next month still do most of it just a little slower :rofl::thumbsup:
 
Working on top of a Coke battery! Frozen on one side and well done on the other!
 
Cleveland Republic Steel and Lorain USS Steel in Ohio Cleveland
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and Lorain
blast+furnaces.jpg
and was a Heavy Equipment operator on a large dozer on those pellet piles
buckeyebowb-lorain-12-28-00.jpg
RESERVE-unloading-at-Lorain.jpg
boy the wind chill BRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRRR no heater or cab
 
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Slab vs Rads....Well, forget the rads, pex the floor, and run with the slab heat for primary heating. And if and when you need to heat up quickly, door open too long, painting a car or just to pre heat until the slab is up to temp, install a hydronic fan coil, on a separate circuit. Keep in mind circuit temp for the floor, has to be mixed down to around 65 to 75 degrees, fan coil can run at your max circuit temp , 120-160. Might cost you a little more now, however, it will pay for itself over time.
 
Think you guys are right, I'll likely go the slab route just wish I could leave it off while not in use:BangHead:. I imagine running it at just above freezing wouldn't take much just hate to increase my wood usage just to prevent freezing.
 
I'm a huge fan of radiant in floor heat but like mentioned earlier it is a constant heat. Your boiler will be running all the time. If you do turn your thermostat down, you will probably need to turn it back up 4-6 hours or so to heat up the slab. I guess it all depends on how you use your garage. If you just spend time out there on the weekends, you could turn it back up on Friday and back down on Sunday. Radiators work well as you know. I like cast iron over baseboard/fin tube. The cast iron radiators provide heat longer at a lower temp (120°) where as fin tube needs to run at a minimum of 160° to be efficient and as soon as the zone pump shuts off, the heat does too. My 100 year old house has both types on 4 separate zones. We have a Weil Mclain energy efficient boiler that works well. It is surprisingly small and only heats a gallon and a half of water at a time. Out old cast iron boiler was probably 100+ gallons and not efficient at all. Your garage could be heated with a small water heater I bet.
 
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