Insulating cement slab?

[Coleman]

Stating in the whelm of looking for a hot tub and lurking on this forum for awhile, the question I have today is When I do get a hot tub I am going to have a cement slab poured for the tub. I have seen a insulated blanket or pad to put underneath the cement . I know a lot of good quality tubs have good insulation inside of them. the insulating blanket was around $70 so the cost wouldn't be that bad, Would this help in the winter? sometimes it will get -10-20 in central KS. Someday I would like to build a enclosure around the tub for the winter time. Is the insulated pad worth the cost? Thanks Coleman

[Topline Mike]

I can't seem to see the benefit of insulation under the concrete, but I guess it might help a little.  I have an insulated shop with 2" styrofoam under the slab with in-floor heat, which makes sense.  Being in the open, I just don't think it's going to save you much.  I would insulate the side panels and use a good cover to help save energy.  Good luck.

[Coleman]

Topline,
 Thanks for the info.
Coleman

[johnnyk]

Hi,

I would recommend putting some insulation between the cement slab and the tub. I used a 4 inch thick XPS insulation foam layer (http://www.finnfoam.com/). That way the tub is not in direct contact with the cold cement and therefore might save some energy.