1) R-value.
Just like your house, the insulation value is the most important factor in keeping electric bills low.
The spa's heat retention is represented by "R-value;" higher numbers = better heat retention.
Ask your local retailer for the R-values on each spa.
The R-value can be increased by adding full foam and upgrading the cover.
2) Full Foam Insulation.
Some spa brands don't come standard with full foam insulation, so be sure to ask for it.
The brand of foam is also important; Icynene is the industry leader for insulation and it recently made its way from insulating your house to insulating your spa.
Icynene has the highest heat retention available and, unlike other brands, does not retain moisture.
Even if you decide against a spa with Icynene foam, be sure to ask if the foam used is non water permeable - it diffuses moisture instead of retaining.
3) Hot Tub Cover.
Your new hot tub will come standard with a cover, however, it may not be the most energy efficient option available.
Be sure to ask for an upgrade! Upgrading your cover can increase your spa's R-value significantly.
Do you already own a spa? A new, highly insulated cover can easily increase your current spa's energy efficient.
4) Circulation Pump.
A circulation pump draws only 0.
4 amps, runs 24 hours, and filters your hot tub approximately 100 times a day.
When you have a circulation pump, the jet pumps don't have to work at heating the water, instead the circulation pump circulates the water into the heater at a consistent rate.
5) Standby Wattage.
People put too much emphasis on "standby watts", but actually, it's best not to make your final decision based entirely on standby watts.
Hot tubs that rank well in this area usually aren't very powerful and are not a great choice if your primary focus is hydrotherapy.
Other Considerations: Don't simply purchase a spa on energy efficiency alone, make sure it fits in with your overall needs.
If your goal is hydrotherapy massage, perhaps paying a few dollars more in electricity is worth the added massage power.