TP Insulation

[Dr. Spa™ Ret.]

Why you guys come to me for this stuff? You think I can just spit out something like, R-14 stops about 90% of heat loss, and R-20 about 95%?

Oh..... well gee... I guess I can  

Seriously though, please remember that this is based SOLEY on insulating ability and does NOT take air infiltration into consideration. It also doesn't take into consideration any leaks from the seam of a cover, nor a cover with minimul insulation along the hinge.

[Steve]

Let's start it in a new thread so as to not hijack this one. It can be specific to covers and chances are we'll get a better response. I'll check back later on tonight or tomorrow. Sound like a plan?

[Dr. Spa™ Ret.]

heh heh heh....... ok, so maybe I didn't read your whole question.. been a long day.

Arctic uses a "cast core" foam, as opposed to EPS. I"m not exactly sure what "cast core" is, but I believe it's similar to extruded polystyrene. Most all spa covers are expanded polystyrene.

The R value of expanded polystyrene, based on 1 of thickness, varying densities;

1.0#        R-3.85
1.25#       R-4.0
1.5#       R-4.17
2.0#       R-4.35

I'd have to look up extruded, but my recollection is R-5 per inch

[Tman122]

heh heh heh....... ok, so maybe I didn't read your whole question.. been a long day.

Arctic uses a "cast core" foam, as opposed to EPS. I"m not exactly sure what "cast core" is, but I believe it's similar to extruded polystyrene. Most all spa covers are expanded polystyrene.

The R value of expanded polystyrene, based on 1 of thickness, varying densities;

1.0#        R-3.85
1.25#       R-4.0
1.5#       R-4.17
2.0#       R-4.35
I'd have to look up extruded, but my recollection is R-5 per inch

Why you guys come to me for this stuff? You think I can just spit out something like, R-14 stops about 90% of heat loss, and R-20 about 95%?

So a 3/2 taper made from 1 Lb. density would have a maximum R-Value of about 12 and a 5/4 taper made from castcore would have a maximum R-Value of about 25.....double. But we do not know the exact cover used by the others in the test.....

And if you are using 5-7 percent more of your energy because of the lower R-Factor in the cover, it would relate to aproxemitly that much more KWH per day in usage for the next nearest compititor to the Arctic which only was what percent higher in operating cost...huh? I think there was pennys difference between the top 2 in the test.

Speculate with me here, if the second place tub had an equal R-Value in the cover which tub would of been on top?

oops sorry. Yes a new thread if anyone is interested. But it has been covered several times previous as Tom mentioned.

[Steve]

Since we're not starting a new thread, here's a question to ponder;

At what point does R Value become redundant in the case of a spa cover's thickness and then instead, become a feature for added strength?

Steve

[Tman122]

Since we're not starting a new thread, here's a question to ponder;

At what point does R Value become redundant in the case of a spa cover's thickness and then instead, become a feature for added strength?

Steve

Local building codes require us to achieve a certain R-Factor in our building practices in walls and attic spaces. I am going to guess here and say these minumums are not the maximum effective R-Factor. I believe for an Attic here in Northern Minnesota it is R-30 minumum. I do not think those kinds of R-Factors are achievable on a managable cover. So my point is, to try and speculativly answer your question Steve, I dout the point of diminishing return is achievable on a managable cover.