Radiant floor heating -- pros and cons

[Wild Turkey]

Considering radiant floor heating for my shop here in Kentucky but I'm wondering about the cost/benefit ratio.

Winters are fairly mild here -- 4000 heating degree days -- and electricity is currently fairly cheap.

I like the idea of the thermal mass of the floor and not needing ducts/blowers, but the extra costs are also a consideration.

What are the thoughts of those who have radiant floors?

[JosephP]

Considering radiant floor heating for my shop here in Kentucky but I'm wondering about the cost/benefit ratio.

Winters are fairly mild here -- 4000 heating degree days -- and electricity is currently fairly cheap.

I like the idea of the thermal mass of the floor and not needing ducts/blowers, but the extra costs are also a consideration.

What are the thoughts of those who have radiant floors?

How much dust will you be making?  Not having a system to suck that into should also play into the decision with a shop.

What are you thinking of using to heat the water?  Low electric rates may still provide benefits.

Will the shop have A/C?  If so, 2 opposing ways to think about that in the equation:
1) You will already have the duct work, so might as well use for forced air heating.
OR
2)  Heat is best delivered from ducts placed low/from the floor rather than trying to push hot air down from above.  A/C is better done from above.  But nobody is doing 2 separate ducting systems.  Up here most HVAC systems have ducts in the floor because heating is more difficult.  However, if you are heating the floor, I would run the air ducts from the ceiling to get better cooling.

[Wild Turkey]

If I go with radiant floor heating I'll be using water from the creek and a big truck radiator for the AC


I've got a 5 hp, 4-bag dust collector that will be put to work plus I'll be building an air filter system to keep things clean.

I'm just trying to decide which way to go. I'd really like radiant floor heat but I'm afraid it's gonna be twice what a heat pump system would run.

I'll also have a wood stove at some point in the future.

So the question remains -- in my "moderate" climate will radiant floor heating be worth the extra initial cost?

[chips ahoy]

If I go with radiant floor heating I'll be using water from the creek and a big truck radiator for the AC


I've got a 5 hp, 4-bag dust collector that will be put to work plus I'll be building an air filter system to keep things clean.

I'm just trying to decide which way to go.  I'd really like radiant floor heat but I'm afraid it's gonna be twice what a heat pump system would run.

I'll also have a wood stove at some point in the future.

So the question remains -- in my "moderate" climate will radiant floor heating be worth the extra initial cost?

Check with Blackhat,he da man when it comes to heating and cooling.



Mel

[tomsteve]

wasnt this a topic just a bit ago?
https://forums.woodnet.net/showthread.ph...floor+heat

[blackhat]

Radiant floor is great in a shop that's kept at a constant temp, it doesn't do fast temp changes.  Insulate under the slab even if you aren't doing radiant.  No air blast stirring up dust can be nice when finishing.  You can install floor to ceiling obstructions without worry about blocking the heat to half the shop, think curtains around a big project being sandblasted, etc.  A small closet to contain the equipment would be a good idea to keep equipment clean and free of contaminants.  I would definitely bring in a waterline and I would install a sump pit near the center.

[Overland1]

I never thought about the slow temperature change with radiant heat. My shop has an over-sized gas furnace and is turned off unless I'm using the shop. The coldest it ever gets in the shop with the heat off is about 40 degrees. I can turn the heat on and in 5 or 10 minutes it is warm enough to take my coat off. The slow temperature change would be an important consideration for me.

[JosephP]

Yeah...you wouldn't put radiant heat in a place you aren't going to use often as the plan with radiant should be to get it warm and keep it warm, not go back and forth.  It uses too much energy to get everything warm to just turn it off an hour later.  The energy savings come after you have the temp up...it takes relatively little to keep it there - even after opening large doors as others have mentioned.  If you open over head doors in a furnace heated shop, you are guaranteed that the furnace will be kicking into high gear

[measure once cut remeasure]

If you choose radiant, you probably don't need a boiler. The boiler I have is optimized to put out hot water at around 180*. You need mixing valves to just add a little of the hot boiler water to the return lines of water to warm it up by about 10*

A hot water heater should be sufficient for just a shop. Ideally the hot water heater can run at a lower temp than the boiler. The hot water heater is much less expensive to buy than a boiler. If you have natural gas, it might work out to be cheaper than electric. One zone should be all you need. But two zones and two separate circulating pumps would give you a safety factor if you were ever away and one pump quit, the other would still function.

You would want to limit the amount of foam floor mats that you have to stand on. I've seen pictures of shops where the floor was covered by foam mats. These would not work well with radiant heat.

Installing tubing in a slab is ALOT easier than installing it between floor joists.