Celtic Hot Tubs Replacement Hot Tub Covers

What size AIRCAP 1™ fits your Celtic hot tub?

Celtic Hot Tubs is a brand of GPM Manufacturing, which shares a Franklin, Kentucky address with Harmonic Hot Tubs and Resort Hot Tubs; Celtic tubs are sold through independent dealers. Since 2026 Celtic has offered two lines: the acrylic Summit line, whose model names end in S, and the Classic line, with shells of high-density polyethylene (HDPE). The tubs Celtic sold before 2026 were polyethylene too. Our fitter lists eleven Celtic models with square cabinets that an AIRCAP 1™ fits: four from the current range and seven earlier models no longer in Celtic’s line-up — the Mystic 120, Mystic 126, Mystic 236, Mystic 118RS, Clover 124, Clover 130 and Clover 250.

Here is how the 11 Celtic models in our fitter map to AIRCAP 1™ sizes:

• The current Mystic 120S and Mystic 118 and the earlier Mystic 120 (2025 and earlier), Mystic 126, Mystic 236 and Mystic 118RS (Mystic Special Edition) are all 78" square and each take the AIRCAP 1™ XX-Small, which fits square spas 77–79".
• The current Clover 250S and Clover 240 and the earlier Clover 124, Clover 130 and Clover 250 (2025 and earlier) are all 84" square and each take the AIRCAP 1™ Small, which fits square spas 83–85".

Many Celtic models share a shell. The polyethylene Mystic 118RS (Celtic’s Resort Series model, later sold as the Mystic Special Edition), the Mystic 120, 126 and 236, and the Classic Mystic 118 sold since 2026 are all built on one 78" square shell; they differ in jets and equipment, not in size. Likewise the polyethylene Clover 124, 130 and 250 and the Classic Clover 240 share one 84" square shell. The acrylic Summit Mystic 120S and Clover 250S follow the same seat layouts as those polyethylene tubs, but they are separate shells.

Mystic 120 and Clover 250 owners: on these two models an S means a different tub, not a different size. In 2026 Celtic reused both numbers for the acrylic Summit Mystic 120S and Clover 250S. Celtic prints the same size for both generations — 78" square for the Mystic and 84" square for the Clover — so a Mystic 120 of either kind takes the XX-Small and a Clover 250 of either kind takes the Small; compare your tub with the photos below to pick the right row. Celtic’s 2024 owner’s manual lists the polyethylene Clover 250 at 78" x 84", but that line was copied from the Solstice 240: the drawing on the same page, the 2024 brochure and Celtic’s own web page all give 84" square.

Measure across the lip. On every Celtic in our fitter the shell’s top lip overhangs the cabinet panels, and the cover rests on that lip. Measure across the top from lip edge to lip edge: a Mystic that measures 79" or less takes the XX-Small, but one over 79" takes the X-Small; a Clover that measures 85" or less takes the Small, but one over 85" takes the Medium.

Every AIRCAP 1™ ships with the Ziptech™ modular skirt system, so you can zip on the right skirt depth for your cabinet instead of ordering a custom cover.

Not every Celtic hot tub takes a square cover. Every Luna is round: the polyethylene Luna 114, Luna 118 and Luna 124, the acrylic Luna 118S, and the Luna 118 Vintage and Luna 118S Vintage in a cypress-wood barrel cabinet. Celtic’s 2026 pages list the Luna 118 at 78" x 78" and the Luna 118S at 79" x 79", but those figures are the diameter of a round tub, and a square cover cannot replace a round one. The Solstice is a rectangle in both forms: the polyethylene Solstice 122, 128 and 240 sold before 2026 measure 78" x 84", and the acrylic Solstice 122S measures 82" x 72". The acrylic Kozy 126S is a 61" x 84" rectangle, and the Charm is a one-to-two-person tub just 48" at its longest, far below our smallest size. The AIRCAP 1™ is built for square cabinets from 77 to 94 inches.

Measure your own spa before ordering — cabinet sizes can change between model years. The SureFit™ measuring guide walks through it in two measurements, and works for any hot tub, Celtic or not.