New to radiant floor heat. Just ran 2000 feet of 1/2 pex in my barn floor in 1000' loops later to find out that probably wasn't a good idea. I haven't went any further as far as hooking up anything to run the system. My question is will it be so inefficient I should just scrap the idea and chalk it up as a loss?
Radiant in slab heat questions
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WorthFlorida
Clinical Trail on a Cancer Drug Started 1/31/24. ☹
A barn floor? What are you trying to accomplish, want to keep warm and up to what temperature. Is it under concrete or a wooded floor? Is the floor insulated? etc, etc. What is the square footage? Inefficiency would come with in a heat loss do to poor insulation otherwise floor radiant heat is quite efficient as far as getting the heat transferred from the PEX to the room. Your question on "efficiency" is thermo transfer of heat or just the cost to run the system? What type of fuel would you be using and furnace.
Here is a place to start for correct sizing:
http://www.supplyhouse.com/sh/control/RadiantHeatCalculator
Here is a place to start for correct sizing:
http://www.supplyhouse.com/sh/control/RadiantHeatCalculator
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It's 1700 square foot pole barn. Ground is insulated pex is in concrete slab. Walls are foamed 10ft ceiling is blown insulation. So as far as the building it is tight. My question was will my radiant heat be inefficient due to the fact I ran 1000ft loops of 1/2 pex. Was planning on running a tankless boiler on propane
Jadnashua
Retired Defense Industry Engineer xxx
The issue may not be efficiency (of energy use), but of its ability to actually push the heated water through the long loops. If it can't push much water, it will quickly reach its setpoint and shut off. It might then cycle frequently and shorten its life without actually heating much. Two issues here: available input BTU, and the effective output BTU to the building. 1000' loops won't be very efficient at transferring heat, nor will it lend itself to evenly distributing that heat as whatever is input at the beginning, cools the water, and there's not much left as you run down its length. You cannot start with super hot water, as that can be dangerous and uncomfortable and damage the floor as well.
WorthFlorida
Clinical Trail on a Cancer Drug Started 1/31/24. ☹
You might want to contact a local heating company that is familiar with what you have. I found a charts and 1000 ft of 1/2 pipe @.01 to .016 gallons per foot. It could be 10-16 gallons just for the pipe and there be a lot of resistance to flow with all the bends. Questions to ask is can a circulating pump usually used for heating systems can push that volume of water 1000'?
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