Lids for the spa and whirlpool ensure good isolation. This cover is made of expanded polystyrene foam (EPS). EPS, usually white, is obtained by combining the chemicals ethylene and benzene to produce a compound known as styrene. When treated with other chemicals, styrene molecules polymerize. To further expand the beads and join them together, polymerizable styrene molecules are injected with low-pressure steam.
The newly expanded polystyrene is now tough and closed is ready for packaging materials (softens, especially fragile items) and insulating buildings. The ratio of strength-to-insulation to foam weight is the reason why insulated spa covers are the market leader with this foam.
The spa lid closes the spa to prevent heat from escaping. They rest on the surface of the hot tub and retain heat when the hot tub water is heated. This cover also protects children and the elderly from accidental falls and dead insects, leaves, and other foreign objects entering the spa.
If you find that the water you are trying to heat can cool off easily even when covered with a spa blanket, likely, your spa cover is poorly insulated and not installed properly. Note that a sturdy spa cover will retain heat regardless of the temperature setting.
Not only does the insulating strength of the spa cover in its EPS foam keep the bill low, but the surrounding foam layer also has its insulating capabilities. This coating adds to the overall thermal resistance of the spa cover. The R-value determines how much heat escapes through the layer over some time.