Hot Tub & Spa Energy Efficiency


What makes a great, efficient hot tub?

It seems that as we get more and more concerned with energy efficiency the Claims from some manufacturers get more and more outlandish.

Apply some common sense when comparing claims from Hot Tub companies regarding efficiency.

The cost of the insulation system is a good indicator of the quality of the insulation system.

There are only two factors to consider; First is the quality of the insulation system (the insulation that keeps the heat in) and second is the ability to reuse the waste heat from the motors.

#1 System -Full Foam with pumps under the spa

  • The best, and most expensive system is a full foam Canadian Icynene foam insulation system with a heat collection system on the pumps located under the spa.
  • It is a true Hybrid system that takes maximum advantage of both the heat retention of the Hot Tub, and heat collection from the motors.

Perimeter foam or wrap system

  • Cheapest to manufacture as it uses the least amount of insulation.
  • Moderate passive use of the motor heat.
  • These systems typically use 1/4 or less of the insulation that a full foam tub uses and therefore do not retain heat nearly as well.
  • Because they reuse motor heat reasonably well ¬†they can be decent systems when done with high density expanding foam but most of these systems are on cheap mass merchant quality Hot Tubs and utilize bubble pack, rockwool, or other “attic type” insulation materials.

Full Foam with pumps outside of the spa

  • Although common 20 years ago only one major manufacturer still uses this and one can only assume it is more for the marketing angle of a unique selling feature than for the quality of the insulation system.
  • Maximum retention of heat on the shell, but pumping the hot water outside the insulation envelope of the hot tub makes zero sense.
  • No reclaiming of motor heat.
  • serious equipment risk in power outages in winter as the equipment is virtually unprotected when it is outside the heat envelope of the hot tub.
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