Another in floor radiant heating question

[green.bubbly]

I will be building a steel building home/garage/workshop in the next few months. I have a few questions about in floor radiant heating I am hoping somebody can answer.

Before I ask my questions, here is a little background. The wife and I live in southern Louisiana so we rarely have a very cold winters. Even when it is cold, we rarely turn the heater on. The building will be around 55 by 60ish with about half of it living area. More than likely we will not have natural gas available although we could get a propane tank installed. the building will have fiberglass batt insulation in ceilings and walls and hopefully sprayed foam in the living area.


Sorry for all the questions but I have no idea how this system performs. I see it being installed on every home improvement show so I know it is viable. I just do not know if it is something I would find useful or worth the expense.

1. How energy efficient is this type of system. It would seem to me that this would not be very efficient unless you had several inches of insulation board under the concrete. The thought of an electric water heater running constantly to heat a concrete floor sounds frightening come bill paying time.

2. Is the in floor radiant heating the main source of heat?

3. One problem we have down here in the south is mildly cold days followed by warm humid days. This causes the moisture in the air to condensate to the cold concrete in garages. Has anybody had any experience with this and would in floor radiant heating stop this?

4. I am mainly thinking about this system for the unconditioned area of the garage/shop. The building will be insulated (probably with fiberglass in the garage area) with open ceilings (14 foot side walls and 5:12 or 6:12 roof pitch.)
Would this system heat the entire area at least enough to take the chill out of the air? If not, what percentage of heat could this system produce?

5. I do like the idea of laying on a warm floor to work on cars. If I left the system off, how long does it take to heat a cold floor?

6. If I used this system in the living area, is it hard to regulate the heat in the room? In other owrds, if we find it is too warm in the room and we turned the system down, does it take a long time to stop radiating heat?


Sorry for all the questions but I ave no idea how this system performs. I see it being installed on every home improvement show so I know it is viable. I just do not know if it is something I would find useful or worth the expense.

 

[nate379]

1. How energy efficient is this type of system. It would seem to me that this would not be very efficient unless you had several inches of insulation board under the concrete. The thought of an electric water heater running constantly to heat a concrete floor sounds frightening come bill paying time.

Dunno compared to other things.

2. Is the in floor radiant heating the main source of heat?

Yes

3. One problem we have down here in the south is mildly cold days followed by warm humid days. This causes the moisture in the air to condensate to the cold concrete in garages. Has anybody had any experience with this and would in floor radiant heating stop this?

Floor would be warm so no condensation.

4. I am mainly thinking about this system for the unconditioned area of the garage/shop. The building will be insulated (probably with fiberglass in the garage area) with open ceilings (14 foot side walls and 5:12 or 6:12 roof pitch.)
Would this system heat the entire area at least enough to take the chill out of the air? yes

5. I do like the idea of laying on a warm floor to work on cars. If I left the system off, how long does it take to heat a cold floor?

depends on slab thickness, how much tubing/how close it is, boiler temp, pump gpm, how much insulation under the slab, etc. From no heat to warm it will take a good day or so to come up to temp

6. If I used this system in the living area, is it hard to regulate the heat in the room? In other owrds, if we find it is too warm in the room and we turned the system down, does it take a long time to stop radiating heat?

Yes. My house and garage are in floor heat. The power was out for 8 hours last week and it was around 5* outside. The temp in the house dropped 2* from 69 to 67*

Also overshooting/undershooting on temp is somethiing I have found happens in my house. We go from temps -10* to 20* almost overnight and vice versa and the temp in the house will swing up or down from 68* by 2-3*

 

[GerryL]

After MUCH debating I ended up with a radiant floor in my shop building. It's a steelmaster 30x50, and I live in western MA. Well the debate wasn't so much going with the radiant floor, but how to heat it. I went with a modulating boiler and am very happy with it. Our climates are very different so I don't know how much help this will be.
My slab is almost 6" thick, and I have 2" insulation under it, 1" around the perimeter of it. If you go radiant, DON'T skip this. You will be heatiing the ground. My propane delivery guy fuels some early systems with no insulation; he said you wouldn't want to pay that heat bill.
Before I heated it and insulated it, I saw the condensation you're talking about. It was just about raining in there throughout the winter. I used 6" insulation provided by steelmaster (white backed as in industrial buildings). No more moisture (except on my 10x10 door which I will probably insulate better).
The floor does stay warm, but not like I expected. I only heat my shop to 58 degrees, so the floor is around 60 maybe; still cool to the touch. But that's all it takes to heat my shop. And the floor is a massive heat sink/source. No quick changes there, so it will retain heat for a long time. In my cold climate that's a good thing. I can open the door and drive caars in/out without making it feel like it's freezing in there, or making the heat cycle. Oh, the floor does dry quickly too; I brought in an ice covered car yesterday and it didn't take that long to evaporate (of course now that moisture is in the air condensing on my door).
As for the initial heating, mine ran for less than 5 hours before the building was up to temp. My boiler burns less than 2 gallons/hour at max output, so that was less than 10 gallons of propane to get it up to temp. Pretty much a non-issue.
I'd check around your area with propane contractors and see if it's popular in your area with that climate.
-Gerry

 

[green.bubbly]

Thanks for the answers and responses. It is much appreciated. ad that was exactly what I was wanting to find out.

Looks like I will not install in in the living area but it might be worthwhile in the garage/shop area. jIf I use it just to keep the floor dry and halfway warm when I have work to do, it would probably be worth it. That of course depends on the price.

Thanks again for the input.