While you're shopping, you may experience several different types of spa insulation. Generally, all manufacturers place hot tub foam insulation along their hot tub shells. Some place spa insulation along the floors, and some place insulation inside the cabinets. These hot tubs are called "partially insulated." Hot tubs that are full-foam insulated - ones that have foam along the shell, the floor, and the cabinet - are the most energy-efficient hot tubs on the market.
While some manufacturers claim that partial insulation forms a "thermal plane" or a "heat keeper" pocket, we believe the most efficiently engineered hot tubs and spas are foam-filled.
You may also hear that full foam insulation makes servicing a hot tub more difficult. This may, in fact, be true. However, it's important to take into account the entire cost of owning your hot tub. If full foam hot tub insulation reduces your energy costs by adding efficiency, is it worth giving up your savings to make hypothetical repairs a little easier? You're probably better off buying a fully insulated hot tub or spa from a hot tub manufacturer with a good reputation, sound warranty, and well-built components. Overall, you'll spend less in the long-run, and enjoy your spa more.