MAAX Spas - Next Generation Copper Insulation for Spa Tubs

The Challenge

For over 45 years, MAAX Spas has been building a reputation of quality and innovation. However, MAAX Spas and all other hot tub and spa manufacturers faced a challenge when the standards of the California Energy Commission (CEC) changed. The standards, not only required manufacturers to meet a higher energy-efficiency standard, but also required them to post energy-efficiency labels to make it easier for consumers to compare products side-by-side. 

The challenge was to meet the CEC standards while maintaining the serviceability to meet the lifetime warranty criteria that MAAX Spas is known for. Their existing spa insulation featured a 4” batting material with a reflective aluminum foil facer in the walls, a plain aluminum foil on the spa floor, and 3”-4” foam in the spa cover (without aluminum). The wall insulation wrapped around the walls of the spas to help hold the heat providing the R value, but the aluminum in the wall and floor was susceptible to corrosion and could lose performance. They needed an improvement in efficiency, and redesigning the spa to make more room for additional insulation wasn’t an option. The challenge was improving the current insulation and providing good R-value with materials that could be warrantied for the lifetime of the product.

The Solution

The team at Sigma Technologies International (Sigma) was able to meet their needs by providing a copper reflective insulation on the cover, walls, and floor. Unlike traditional insulation products, reflective insulation works by reflecting radiant heat through air space rather than insulating against conductive heat transfer. Radiant heat is the primary mode of heat transfer, and with the spas operating at high temperature and with a big temperature difference between the spa and the outside air, even a small improvement in insulation can make a big difference in efficiency.

Another limitation to maximizing the insulation is the space requirement. With only a few inches in the walls and even less in the spa cover and floor, filling the cavity with more fibrous insulation wasn’t an option. Sigma’s reflective insulation, on the other hand, is no thicker than their current aluminum foil, and achieves a higher R-values in smaller spaces than traditional fibrous insulation. Sigma’s copper reflective insulation in a wall, for example, achieves R-2.57 when facing into a 0.5” air space. Copper achieves a higher reflectivity than aluminum, and isn’t as prone to losing reflectivity to corrosion.

Lastly, there’s the concern about moisture. Batt insulations, like fiberglass and cellulose, lose their insulating value when they get wet. Although the tubs are designed to not leak, all spas create humidity. While aluminum-based reflective insulations don’t absorb moisture, the aluminum surface will oxidize and corrode in humidity. To meet this challenge, Sigma produced a reflective insulation based on copper rather than aluminum. As a “noble metal”, copper is significantly more corrosion resistant than aluminum, so Sigma was able to ensure that the insulation would continue to perform, even under harsh conditions.

The Results

By making an addition to their insulation, MAAX Spas was able to advertise a higher energy-efficiency, without making any major changes to the spa itself. Their new insulation worked great in tight spaces, at high temperatures, and would be minimally affected by moisture. After installing Sigma’s copper reflective insulation in the walls, floor, and cover of the spa, in combination with the insulation they already had, MAAX Spas could beat the new CEC standard by 33%.