Pool Cover And Insulation Questions

[tsf]

Hi

I'm building an above-ground training pool approx 17ft x 9ft x4ft using the "endless pool" kit (vinyl liner in a stainless shell). I'm in Northern England and want to use the pool all year round. So I need to understand about heat loss and insulation!

1. Firstly, will I get much better surface insulation if I get a hot-tub style cover? I can order what is effectively 2 regular hot-tub covers side-by-side to cover the pool. Will this give me a significant reduction in heat-loss over the winter, compared to a regular retractable cover? I can deal with the hassle is it's a big saving.

2. Also should I be insulating the sides of the pool (between the stainless shell and the wood cladding). I have seen some bespoke pool insulation boards on various websites. Is this worthwhile for my small pool?

3. Is it worth insulating between the pool and the concrete slab?

Thanks for your help

[chem geek]

If you are wanting to keep your pool water warm in the winter when it's very cold outside, then yes the extra insulation will help. The type of cover definitely makes a difference. I have a relatively thin electric opaque safety cover and it cuts heat loss roughly in half, mostly from eliminating evaporation. However, the cover feels the same temperature as the water so there is still a lot of conduction/convection of heat if there is any air movement. With a bubble-type cover, I would probably have the heat loss cut by another factor of 2, so 1/4th compared to no cover. A hot-tub style highly insulated cover would retain heat even more though is obviously more of a hassle. The key is having a good enough seal -- it doesn't have to be air-tight, but should not allow for significant air movement/exchange.

The next most important would be the sides of the pool which can be insulated.

Light concrete has somewhat lower thermal conductivity compared to water -- 0.42 vs. 0.58 Watts/(m•^oC) -- though is better than dry earth at 1.5 or glass at 1.05. It's primarily the thickness of the concrete that helps. I'm not sure what sort of insulation would work that would handle the weight of the water in the pool (i.e. it would be very compressed). It's probably the least important to insulate compared to the pool surface and sides. See this chart for some relative thermal conductivity where you multiply by the temperature difference in ^oC and divide by the thickness of the material in meters to get Watts per square meter heat loss.

Don't forget to insulate around the pipes between the pump/filter and the pool. I know that in our own pool we lose heat when the ground is cooler in the winter by not having insulation around the buried PVC.

My wife and I have talked about keeping the pool open through the winter, but the bigger issue is that of the air temperature being so cold outside. It generally makes swimming unpleasant. So unless you were planning on enclosing your pool in some sort of heated dome, then you should consider whether you would really use the pool when the air temps are so cold. I suppose people run out and use their hot tubs in this sort of environment, but that's different than swimming in pool water that is relatively cooler.

[Trigger]

I'm not familliar with the "regular retractable cover" ? Are you talking about the standard bubble wrap style that one might see on a typical pool? if so, YES. A hot tub cover would Greatly increase your R factor. If it's another style could you provide more info?

How would you open and close the hot tub covers? On a typical hot tup, the cover is usualy mounted to the tub with a manual lifting system. Are you planning on mounting cover lifters, or simpley moving them off and on manually? That could get to be a pain, espically so in the dead of winter. Also keep in mind that what ever cover you have, you'll need to keep the snow off of it as well.

I'm not familliar with heating pools, but I an familliar with using hot tubs in the winter in New England, and wonder that unless you pool is enclosed in a green house, or or artium style enclosure, keeping a conventional (non insulated,) swimming pool heated in the winter could be a loosing and exspensive battle. Does the manufacter have others who use thier pool all year in freezing climates?