Hot tub Insulation (Help)

[chusc28]

Hello

I am new to the forum. I have recently receive a second hand hot tub from my grand parents who can no longer get in and out of it. They also never used it during the winter.  It is a Gulf Coast spa(out of business) Lx7000.

My goal is to have an efficient(or as efficient as possible) hot tub to use during the winter.

Existing Condition
For reasons unknown, the tub has 1/16 of and inch of some kind of spray insulation. (Virtually no insulation) Location- Northeast USA

After extensive research, I haven't found concrete answer. Many solutions don't provide detailed solutions which a risk/benfit solution. I am hoping to start a constructive conversation to help myself and others like me.

Spray Foam (Closed Cell) -
Pro - 5-6 R Value/Easy to install in problem areas(Corners)
Con -Very difficult to repair hot tub/Dangerous Chemicals (DC)/Can damage equipment jetholes, tubing, etc (DE)

Spray Foam (Open Cell)
Pro - 2-3 R Value. Easy to install in problem areas,
Con - Moderately difficult to repair hot tub (but easier than closed cell), Water permeable, (DC), (DE), Limited availability

Rockwool
Pro - Easy install, Water Resistant
Con- Lower R values than foam.

Fiberglass or Fiberglass in Bags
Pro - cheap
Con - short term solution, Any moisture will greatly effect fiberglass R value

Reflective Insulation
Pro- Good to use as supplementary insulation
Con - Can not be used as primary insulation

I often see people posting whether or not spray foaming hot tub is a good idea but they never post a detailed solution. It sounds like it's the only viable option. The only foam I ever see used is closed cell foam. Would open cell(easier to remove) with a thicker coat be better.(Cuz of lower r value.)  And if it is where can I get it at a reasonable price.

The other comment I always see is, "you should have spent more money on nicer tub". As I mentioned, I got a free second hand tub from my grand parents who can no longer get in and out of it and don't use it in winter. I would like to use it during the winter.

Does any one have any additional info or recommendations for my situation. Any info is appreciated.

[Hottubguy]

I would just use fiberglass insulation in sealed bags to limit moisture getting in. It's cheap will be somewhat effective. Chances are a older gulf coast spa probably won't last much longer so it wouldn't be worth sinking a ton of money on insulation in it. One of the brands I carry, there lower end line is insulated similar. I try not too sell them very often but when I do I tell people to insulate them that way

[BullFrogSpasMN]

depending on how much you would actually use, spray foam will cost more than the tub is worth to be honest.  I agree with Hottubguy, just purchase a high R value Fiberglass style in bags, I would recommend the same thing when I used to sell Nordic Spas, another company that "half insulates" their spas so to speak.  Of course make sure the cover is still in good shape otherwise all the time/effort into insulating the spa will go up into the air...literally :-)

[Tman122]

Yea if you can get all the panels off and stuff in some bagged insulation, be meticulous, then add a wrap of some reflective R4 or as thick as you can install and still get the sides back on solid. This would likely be the easiest and most cost effective improvement. But don't expect 100's of dollars, more like tens. Make sure the cover is solid and get a floating foam blanket (pain in the a** but worth the effort for winter season)

Keep the pumps and controls open enough to breath. If you wrap allow some adjustable leakage at the equipment door (vent). Careful on air tightness.

[Hottubprosne]

Don't use fiberglass to insulate if its not in a bag anytime you use the hot tub the air jets are drawing air from the same chamber as the insulation and if you ever have to fix it get ready to itch. Putting it in bags reduces the insulating properties of it. Go get denim insulation stuff 2 or 3 bags full into it works great no itch. We use this method on used tubs works great.

[jmk1234]

Yeah with spray foam, if you develop a leak somewhere you got to hack it off to find out where its coming from. I hear the wraps work really well.

[Dr. Spa™ Ret.]

I've had great luck scavenging packing peanuts and putting them in bags.I once even filled the entire underside of a spa with them (equipment was at a remote location).

[Tman122]

If you use spray foam coat all pipe and fittings with Pam cooking spray before you spray foam.