When you're shopping, consider the following features of a spa cover:
Safety Requirements: Hot tub covers should meet safety requirements for static load (amount of weight the cover can withstand), perimeter deflection (prevention of objects passing between the hot tub cover and the side of the hot tub), and other requirements, such as labeling, fastening, and surface drainage. The American Society for Testing and Materials (ATSM) sets these standards.
Vinyl: Hot tub covers should be treated with mildew and UV inhibitors, to withstand constant attack from the elements, and the water inside the tub. The bottom side vinyl must also be constructed to withstand wear from hot tub chemicals.
Foam Core: Hot tub covers are usually priced based on the density of their foam cores. Density generally ranges from 1 lb. to 4 lb. This foam serves as insulation, to keep your hot tub water's heat from escaping when the hot tub is not in use. A good spa cover will have a tapered foam core that allows for run-off of excess water. The foam should also be lightweight, so you'll have less trouble lifting the cover.
Heat Seal Gaskets and Hinges: Hot tub covers fold, and this is often where heat is lost. Your spa cover should include gaskets that seal the two halves of the cover when it is closed. Spa covers should also have reinforced hinges to handle its weight when folded and unfolded.
Locking Hardware: A hot tub cover should meet the ASTM's standards for locking safety. Locks are often modeled after the quick-release buttons found on sports equipment and should lock individually with a key provided.
Hot Tub Cover Lifter: Well-insulated hot tub covers, by nature of their design, are heavy. Many consumers opt to buy a cover-lifting device to assist with placement and removal of the cover. There are a many kinds of hot tub cover lifters. The most common use a metal bar in the fold of the cover, with a handle for leverage. After the cover is folded, the handle is lifted upward, and the cover hangs on the back of the spa. When you're shopping for a hot tub cover lifter, consider the following: