R-value

[Dr. Spa]

First off, I question the thickness. 4 x 3? It's becomming more and more rare to find a cover with only 1" thickness difference. There's not enough slope for water run-off and they tend to break prematurly. HOWEVER, it's not unlikly for a company to give more NOMINAL ("average", if you will) measurements.

It's also not unheard of for a company simply to LIE and call a 4 x 2 cover 4 x 3 (I personally know of a number of companies doing this, though the current common thing is to call a 4x2, 4x2-1/2). The taper of a cover is TECHNICALLY based on a 4' wide piece of foam, and face it, most covers are 7' to 7-1/2' across, making the foam 3-1/2' wide......... so, who'll know the difference?

That said, a true 4x3 cover in 1.5 pound foam has an R value of 16.5, 2# foam 17.2. Now this is based on a cover 8' square, and averaging the thickness. A smaller cover will have a greater R value since the thinner part of the foam is cut away.

You can do your own calc. Add the thick side of the cover to the thin side and divide by 2. Thsi give the average thickness of the foam. 1.5# foam has an R value of 4.17 per inch, 2# foam 4.35 per inch. Then add 2 for the vinyl, poly wrap, and whatever else is surrounding the foam.

THEN, you really have to subtract for the hinge area. If the hinge is uninsulated you can have a gap up to 1" wide running the entire width of the cover, insulated only by the material making up the hinge. Sorry, I've never come up with a calculation to figure the exact amount to deduct.

I don't sell spa's, I have purchased a Great Lakes because the insulation skeem from the factory matched what I wanted to make my modifications. I took a brand new spa and voided the warranty the first day I owned it by ripping it apart and modifying it. It is 5 years old and has the original 4-3 tapered cover. We can ask the Doc about the R-Factor on a 4-3 cover but I will assume around r20? Doc? Foam density 2 lb. 1.5 lb. loads of variables Mine is a 1.5 lb. foam filled.

[Roger]

First off, I question the thickness. 4 x 3? It's becomming more and more rare to find a cover with only 1" thickness difference. There's not enough slope for water run-off and they tend to break prematurly. HOWEVER, it's not unlikly for a company to give more NOMINAL ("average", if you will) measurements.

It's also not unheard of for a company simply to LIE and call a 4 x 2 cover 4 x 3 (I personally know of a number of companies doing this, though the current common thing is to call a 4x2, 4x2-1/2). The taper of a cover is TECHNICALLY based on a 4' wide piece of foam, and face it, most covers are 7' to 7-1/2' across, making the foam 3-1/2' wide......... so, who'll know the difference?

That said, a true 4x3 cover in 1.5 pound foam has an R value of 16.5, 2# foam 17.2. Now this is based on a cover 8' square, and averaging the thickness. A smaller cover will have a greater R value since the thinner part of the foam is cut away.

You can do your own calc. Add the thick side of the cover to the thin side and divide by 2. Thsi give the average thickness of the foam. 1.5# foam has an R value of 4.17 per inch, 2# foam 4.35 per inch. Then add 2 for the vinyl, poly wrap, and whatever else is surrounding the foam.

THEN, you really have to subtract for the hinge area. If the hinge is uninsulated you can have a gap up to 1" wide running the entire width of the cover, insulated only by the material making up the hinge. Sorry, I've never come up with a calculation to figure the exact amount to deduct.

I knew you would come through Doc and you are correct I believe it is probably a 4x2 my bad. And I would go measure it right now but it is buried in 2 feet of snow and I may not see it until tonight. I know it's still there though I heard it runing last night during it's filter cycle. So Brulan I was real close on my R-Factor caculations because I also use a foam floating blanket.

[Brulan1]

I don't sell spa's, I have purchased a Great Lakes because the insulation skeem from the factory matched what I wanted to make my modifications. I took a brand new spa and voided the warranty the first day I owned it by ripping it apart and modifying it. It is 5 years old and has the original 4-3 tapered cover. We can ask the Doc about the R-Factor on a 4-3 cover but I will assume around r20? Doc? Foam density 2 lb. 1.5 lb. loads of variables Mine is a 1.5 lb. foam filled.

20 for a cover is exaggerated as the average in the industry is 12

[Roger]

20 for a cover is exaggerated as the average in the industry is 12

Yes but this was a upgraded cover and as I have stated before in the colder climate areas it is, in my opinion, the most important option you could choose. As 80 percent of the heat loss on all brands is through the cover. So a cover upgrade and a floating thermal blanket no matter how much of a pain it is to remove and replace is a good investment for energy savings. Look at the Arctic brand, they can use the same amount of power to operate as a brand with 5 times the r-factor on the side walls simply because an upgraded or higher R-factor cover is standerd. (don't fret Arctic fans I am talking about non run times 18-20 hrs a day when heat is not being generated from the motors to create the r-factor on the side walls they rely on)

[Brulan1]

Yes but this was a upgraded cover and as I have stated before in the colder climate areas it is, in my opinion, the most important option you could choose. As 80 percent of the heat loss on all brands is through the cover. So a cover upgrade and a floating thermal blanket no matter how much of a pain it is to remove and replace is a good investment for energy savings. Look at the Arctic brand, they can use the same amount of power to operate as a brand with 5 times the r-factor on the side walls simply because an upgraded or higher R-factor cover is standerd. (don't fret Arctic fans I am talking about non run times 18-20 hrs a day when heat is not being generated from the motors to create the r-factor on the side walls they rely on)

I totally agree with you on that Roger.