Simply put, better-insulated hot tubs use less electricity and are cheaper to run. Most premium North American spas manufacturers use Urethane Foam Insulation as the preferred method for multiple benefits. Foam insulation acts as a sound barrier, which can decrease plumbing and equipment noise. Foam insulation also acts as additional support for plumbing components, resulting in less movement and stress on joints and fixtures. In the high humidity environment of a spa, it is critical to use insulation which is moisture resistant and able to maintain structural integrity after years of being exposed to the temperature variations and stress of spa operation. If the insulation absorbs water or allows no drainage, water build up over time could produce mould and other organisms in the shell area which could be a health concern. Water-logged insulation can also sag and deteriorate, resulting in areas of the spa not being insulated and increasing energy costs to run your spa.

Icynene Full Foam Insulation
Used as a premium insulation designed specifically for use in spas. The high insulating value of Icynene provide an average insulating factor of R50, with special characteristics which allow leaks to be contained and quickly removed from the insulation. Foam insulation systems have been proven to have fewer leaks as there are less stress areas and movement on plumbing fittings. Master Spas add a rigid foam layer on the shell and all the plumbing to rigidize the pipes so there is no movement in them when the jets are switched on. Foam insulation provides excellent sound absorption characteristics, reducing plumbing and equipment noise and vibration.

Full Foam Insulation (Urethane)
Used by most premium spa manufacturers for high insulation value and plumbing support. However, In the event of a leak, the foam insulation is pulled out around a lot of the acrylic as it is impossible to locate the problem area. When Urethane foam gets saturated with water, it will absorb the water and loses its insulating properties. The foam insulation's structural integrity does not remain.

Perimeter Insulation / Dead Air Space / Heatlock
This system involves a layer of rigid urethane foam being sprayed on the shell floor, rim and cabinet walls, leaving open air space in between. The area needs to be completely sealed as a vacuum to truly be a dead air space and provide high insulation value. This system provides no support to the plumbing and often causes overheating of equipment components with no venting provided in the sealed cabinet. Claims of the pump's heat being used to heat up the shell are false as 95% of the time the pumps are off, so again we have clever marketing trying to dupe the unsuspecting customer. In reality, this is a factory's cost saving method for manufacturing than using foam insulation around the shell which can add $400 to the cost of each spa.

Skim Coat
This type of insulation involves spraying a few inches of rigid urethane foam over the spa shell surface. The plumbing lines are not insulated or supported, which can cause strain on joints and fixtures with the weight of the water-filled hoses and jet action. There is also no sound absorption quality to this insulation type.

Mineral Wool
This insulating system is quickly degraded in the high humidity area inside a hot tub cabinet. As the insulation absorbs and retains water, the weight causes sagging and reduced insulation value, as well as potential mould collection.

Foil-Lined Insulation Panels
This is a highly efficient insulating system in radiant heating, such as reflecting solar heat. This system, however, becomes only a slight barrier in a hot tub environment which transfers heat through conduction or convection.

What's Right For You?
Make sure that whatever system you choose matches your environment as well as your budget. Ask for documentation from the manufacturer in regards to energy requirements and don't accept anything less than unbiased third party reporting.