Foam Or Perimeter Insulation... Why Not Both?

[ChicagoMike]

I have only had my Jacuzzi for about a month and it is still in the 80's so I have no idea how well it insulates yet, But when I had the front cover off, I was less than impressed with the "full foam" insulation. Taking the other sides off I was relieved to see it was much better. Still I know soon it will get real cold and stay there for 4-5 months. I decided to do some insulation upgrading before I get my first winter electric bill.

I used foil backed 1" foam board for the perimeter and "Comfort Therm" batts for the open area. Comfort therm has plastic on all sides and I slid back the sleeve, cut out some material and then folded over the sleeve and taped it with packing tape. So there is no loose insulation to get into air vents, motors, etc.

I also added an wireless indoor/outdoor thermometer in the control area. I stole this idea from someone here on the forums. I had it unplugged with the cover off for about 4 hours, the temp fell to 98 from 102. When I turned it back on, I also turned both pumps on high (I rewired it for 60A while in there today). I ran it for an hour with the cover off. It was low 80's today with a hot sun on the control side of the unit. The internal temp reached 117F. I don't know what it would have been at without the added insulation or if it would have been different at all. Normally it would not have had to run that hard, except on a refill. And the sun was really hot on that side, I mean the cover was hot to touch before I ran the motor, so I don't think in the cooler months there should be any problem. I took the center foam board out to let the vent slots in the cover be open.

Front compartment with not much insulation

Side and back compartments have much better foaming coverage

I bought some 1" foil covered foamboard and Comfort therm insulation

I cut the foam board to fit the gaps. It fit like a dream.

I used foil tape to hold it in place and seal the gaps.

I put the long sections of the Comfort Therm in the front, trying to stay away from the motors andf heater.

Then I put panels on the front too. I ended up cutting 10" off the top of the middle one because the outside panels have some slots for air movement and I didn't want to cover them.

[Firewire]

Thanks for the pics. Never have owned a spa before it is good to see how easy it can be to add insulation.

[B0Darc]

yeah nice work and post. I know there are alot of posts along this line but having read widely on this subject I have also read about some damage to tubs/shells from overheating. I'm not saying you should worry about overheating, and it sounds like you are applying some good science by monitoring temperatures inside the cabinet. Hey seen those remote thermometers where you put the sensor outside and have the monitor inside? hmmm that could be informative real-time, then you could still get some use from it post-experiment.

I too was very disappointed when I checked out my insulation, and kinda had plans to do something similar. However after watching the solar heating effects this summer (My cover is a dark color and gets direct sun) I was noticing how insulated it actually was because in the early morning hours when I got in this summer it was heated above the thermostatic temperature... long after being exposed to any sun. I have also read on here folks talking about damage (blistering etc) on spas that went overtemp. All spas are different and local weather obviously is different, but we all may be interested in more live data downstream as it gets colder.

I think spa manufacturers are trying to find a middle ground in terms of insulation, and we all know some spa manufacturers that cater to Northern climates... but we all don't live up North, and actually heat build up might be our problem in warmer climates. I don't think manufacturers are trying to save 10$, I think it may just be a careful decision based on satisfying the minimal needs and avoid any over-insulation caused damage because of combined sun and motor heat in a fully/maximally insulated spa. You fit the "Northern" description and it makes sense, but I'm saying that by default all spas likely come with nominal insulation for some scientific reason... lower operating temps for electronics and motors could translate into longer lifecycles and save more money in the long run (repairs) over the cost of heating the water.

Great post... professional even! Still may just do some of that myself come Frost.

[ChicagoMike]

I forgot to mention my wireless indoor/outdoor thermometer has a min/max feature. It is morning now and I can tell the highest it has gotten since yesterday afternoon is 98F inside. I wish I had taken measurements before, so I know what it used to run at.

I forgot to mention it is quieter too. Now watching TV while soaking works better too: http://www.poolspaforum.com/forum/index.php?showtopic=13141

[ChicagoMike]

It seems most of my high temps are almost entirely due to the hot sun. The only time the inside temps exceed 100F is during the afternoon on a hot sunny day.

I'll probably never know for sure what the savings are, but for $60 I think it was a good idea. Plus I really like how much quieter it is, last night we watched Eureka and had a few beers in the tub.

[Biz]

Where did you purchase you wireless indoor/outdoor thermometer? What brand is it and where did you install it on the tub?

yeah nice work and post. I know there are alot of posts along this line but having read widely on this subject I have also read about some damage to tubs/shells from overheating. I'm not saying you should worry about overheating, and it sounds like you are applying some good science by monitoring temperatures inside the cabinet. Hey seen those remote thermometers where you put the sensor outside and have the monitor inside? hmmm that could be informative real-time, then you could still get some use from it post-experiment.

I too was very disappointed when I checked out my insulation, and kinda had plans to do something similar. However after watching the solar heating effects this summer (My cover is a dark color and gets direct sun) I was noticing how insulated it actually was because in the early morning hours when I got in this summer it was heated above the thermostatic temperature... long after being exposed to any sun. I have also read on here folks talking about damage (blistering etc) on spas that went overtemp. All spas are different and local weather obviously is different, but we all may be interested in more live data downstream as it gets colder.

I think spa manufacturers are trying to find a middle ground in terms of insulation, and we all know some spa manufacturers that cater to Northern climates... but we all don't live up North, and actually heat build up might be our problem in warmer climates. I don't think manufacturers are trying to save 10$, I think it may just be a careful decision based on satisfying the minimal needs and avoid any over-insulation caused damage because of combined sun and motor heat in a fully/maximally insulated spa. You fit the "Northern" description and it makes sense, but I'm saying that by default all spas likely come with nominal insulation for some scientific reason... lower operating temps for electronics and motors could translate into longer lifecycles and save more money in the long run (repairs) over the cost of heating the water.

Great post... professional even! Still may just do some of that myself come Frost.

[Peter Smit]

Where did you purchase you wireless indoor/outdoor thermometer? What brand is it and where did you install it on the tub?

There was an answer on this in: http://www.poolspaforum.com/forum/index.ph...712&hl=foil

Walmart $15