radiant insulation

jack z_2

I am in the process of completing construction on a new house. The heat is all radiant - Climate Panels on the first and second floors and tubing embedded in concrete in the basement. The insulation is foam. The insulation contractor foamed the joist space between the first and second floors and also did the rim joist area in the basement. The rest of the area under the first floor was not insulated because some of the mechanicals had to be completed. The heat has been fantastic - we have had no problems maintaining a comfortable temperature in the house even through some very cold weather(0 F). Will I gain anything by insulating the joist space between the basement and first floor? The house is 3500 square feet and I used approx 760 gallons of oil last year.

Mike T., Swampeast MO

As long as the basement isn't overheating relative to the first floor I don't think you'd have much to gain.

Mike T., Swampeast MO

Is the basement floor itself sufficiently warm?

jack z_2

The basement is very comfortable. It is the same temperature as the first floor.

ScottMP

Mike

The first floor heat is going down to the basement level which is a downward loss for the first floor. I say insulate !

Scott

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Mike T., Swampeast MO

Scott

I agree, but if conditions on both levels are being maintained as desired does it really matter?

Isn't the downward loss removing some of the load from the basement slab? Presuming the basement slab isn't too cool wouldn't increasing the load it must provide actually increase the heat consumption a bit due to downward losses from a now warmer slab?

I honestly thought of exactly what you mentioned, thus those two specific questions.

jack z_2

The basement is going to stay unfinished for the foreseeable future so the insulation will be exposed. Anybody have any suggestions on what type of insulation to use in this area. I'm not that crazy about using unfaced fiberglass batts in an area that won't be covered.

Mike T., Swampeast MO

Would you prefer that the basement be cooler?

If so, is sprayed-on foam insulation available in your area? That's probably the "best" if available. Carefully fitted rigid insulation up against the floor as tightly as possible is likely the next best. With patience and time you can do a very good job at low material cost. Seal any visible gaps (inevitable) at edges/joints with cheap latex caulk bought by the case. In places where plumbing/wiring force you to install short pieces, consider two half-thick layers with staggered joints.

If you have warm, humid summers I would NEVER install fiberglass in that application!

Unknown

I'd rather meet a load with a slab than jack up already higher climate panel temps any further than they need to go. But you do have a point worth considering.

Mike T., Swampeast MO

Well spoken and taken Rob!!!

In light of what I've been reporting recently how could I have neglected to consider a higher supply temp requirement?!?!?!

Once again, a seemingly simple question where the answer is anything but

jack z_2

Let me see if I've got this straight. By insulating under the climate panels more of the heat being produced by the tubing in the climate panels should go where it is supposed to go - to heat the first floor and if I understand correctly the only drawback would be that the basement would possibly be slightly cooler. One last question - if I used a rigid foam board I assume it would be placed directly against the subfloor. What thickness of foam board should I use in this application? Thanks.

[Deleted User]

Rule of thumb...

You want 2 times the R value below the heat source as you may have above it.

ME