Hot Tub Insulation Systems

There are Basically three types of insulation systems used on hot tubs.

Perimeter Insulation (The Worst)

Spas that use this system: Walmart, Costco, Home Depot, Arctic Spas, Sunrise Spas, Hydropool, Canadian Spa Company.
One of the older system is a perimeter insulation system or “heat lock” system although not very effective it is still widely used because it is the least expensive system to manufacturer and It uses the least amount of insulation.  It is also the one with the most misinformation in the sales presentation.
This systems uses a small amount of insulation around the inside of the skirt. In the best case it is 3″-4″ of Poly based expanded foam, in the worst case it is a bit of attic insulation stuffed into a bag or a sheet of mylar coated bubble pack wrapped around the outer frame.
In the old days we used this system because the old poly based foams would harden up over time.  With these old expanding foams if you filled the cavity and covered the plumbing it was a nightmare to find and fix leaks. The foam was so hard you literally had to chip it out with a hammer and a chisel. With the advent of the Canadian made Icynene foam system this all became invalid. This stable expanding foam system while very expensive has some great features. Firstly it never hardens, this means if you ever have a leak it is easy to find and fix. All you do is touch the foam until you feel a wet spot then pull the wet foam out with your fingers. In the middle of the wet spot is the leak. you repair it and because this foam is also environmentally friendly you can spray it on site and replace the foam after repair.
  • The Pitch
The sales pitch centers on scaring you into thinking if you have a full foam system you will have nightmares with fixing issues down the road and on trapping and reusing the waste heat from the motors. The repair pitch is true on spas using poly based foams but completely invalid on hot tubs using the Canadian Icynene system. as for trapping the motor heat this is a smattering of truth and half truth.
The bottom line is there is simply not much insulation in these systems, a well foamed spa will have 5 to 10x more insulation. There is no magic bullet here folks more insulation means less heat loss and the modern systems use active heat recovery systems that take the motor waste heat and inject it directly into the water, recovering twice as much waste heat as these passive systems.
  • The Verdict
  1. Cheapest to manufacture.
  2. Least amount of R value and insulation.
  3. Mid grade motor waste heat recovery.
  4. Most likely to leak as plumbing is unsupported.
  5. Midgrade freeze protection in power outages.
Full Foam systems external pumps (mid grade system)
 
Spas that use this system: Beachcomber, Hydrolux, Sansi.
The oldest system is a full foam system with the motors out side of the spa usually under a step .It is not very widely used anymore because of the loss of reclaimed motor heat and the risk of equipment damage on power outages. It uses the same amount of insulation as a full foam with internal pumps except in the corners where the foam is already the thickest. on the other 90% of the hot tub it is the same amount as a full foam with internal pumps.
Although marketed as a new “Hybrid technology” its actually the opposite. Hybrid means a mixing of two or more technologies to get a the best of both systems. this system simply insulates the hell out of the shell and totally ignores the waste heat from the motors. The fact that it pumps all of its hot water outside the insulation envelope of the hot tub into the virtually uninsulated equipment area makes no sense at all.
  • The Pitch
The sales pitch centers on the amount of foam. Its a great, easy pitch, you simply say it has the most foam so therefore the best heat retention and therefore the best system. But it ignores 3 vital flaws…
  1.  You loose all the waste heat from the motors! this is huge, a spa with a good waste heat recovery system can maintain a temperature of between 90 and 95 degrees fahrenheit with the heater disconnected just by collecting the waste heat  from the motor!
  2. You pump all you heated water outside of the heat envelope of the hot tub! This is insane… It’s akin to running your plumbing through the nearest snow bank in the winter, the heat loss is huge.
  3. If the power goes out you have an almost immediate risk of equipment freeze up because the equipment is in a virtually uninsulated area.
The bottom line is these systems only have a tiny amount more of insulation in the bottom corners where the insulation is already thicker than 90% of the rest of the spa. The added value of this tiny bit of extra insulation is negligible while the wasted motor heat and heat loss from the water leaving the insulated area and freeze up risk is huge.
  • The Verdict
  1. Mid Price to manufacture.
  2. Good r value and insulation on shell but offset with almost no equipment insulation.
  3. Zero motor waste heat recovery.
  4. High freeze up risk during power outages.
  5. Hot water is pumped through almost 3 feet of pipe and equipment that has virtually no insulation.
Full Foam systems Internal pumps (Top System)
 
Spas that use this system: Master spas, Clarity Spas, Healthy Living spas, Down east Spas, twilight Spas, H2x swim spas, Michael phelps spas, Four winds Spas.
This is a true “Hybrid” system that uses a High grade Icynene insulation system is with an integrated heat recovery system for the motor waste heat.
These systems use the Canadian Icynene foam insulation system and have 5-7x more insulation than perimeter systems and virtually the same r value as full foam systems. This system while it is expensive, removes the old problem of plumbing access as not only is it environmentally friendly so you can re foam on site, but it also does not break down or harden over time so it retains its R value 90% better than the Poly based foams used on most spas. It can be removed easily for equipment access and makes leak detection a snap. It is the most expensive insulation system on the market and has the best heat retention of any insulation system on any spa.

These systems also use an active heat reclaiming system that collects the waste heat from the motors and injects it directly into the water. This is so effective that even with the heater disconnected these spas will remain around 95 degrees just from the reclaimed waste heat.

  • The Pitch
Lots of Foam, great equipment protection in power outages, and active motor heat recovery make this system easy to pitch.
  1.  You collect all the waste heat from the motors! This is huge, This system can maintain a temperature of between 90 and 95 degrees fahrenheit with the heater disconnected just of the heat recovered from the motor!
  2. You keep all your heated water inside of the heat envelope of the hot tub.
  3. If the power goes out you have days before there is any concern of equipment freeze up as the equipment is sitting right underneath the world biggest hot water bottle… The hot tub!
The bottom line is these true Hybrid systems take the best of all the systems. With great heat retention,  great use of the motor waste heat, and great equipment protection you simply can not beat these systems. The only downside is the cost to manufacture these systems it is 4-6x more expensive to make than the cheap systems but the savings on operating costs over the long haul are huge.
  • The Verdict
  1. High Price to manufacture.
  2. Good r value and insulation.
  3. Active motor waste heat recovery.
  4. lowest freeze up risk during power outages.