12- and 13-foot swim spas

Less than the length suggests. The spec-sheet length is the cabinet, with the walls, seats and equipment bay inside it. 10 of the 41 makers' sheets here give an open swim length, from 6′ 1″ to 9′ 4″ (median 8′). Across every swim spa that publishes both, the open water runs a median 68 in shorter than the cabinet.

Where a sheet gives no open swim length, ask the dealer for it rather than working it out from the cabinet. Our guide to room to swim explains how much room a swimmer needs.

Of the 41 here, 38 push the water with jets and for 3 the maker doesn't say. Jets fire water through a few nozzles, often with air mixed in. A propeller or a paddlewheel turns behind a grate and moves a wider column of water.

What you feel is the shape of the stream: how wide, how deep and how steady it is. On a running display, hold your hand across the current at full speed: it should feel wide and even. The guide to swim spa jets vs propeller compares the three, Endless Pools vs Master Spas compares two makers that sell both propeller and jet models, and the best swim spas for lap swimming are ranked by current type and open swim length.

Where there's a list price or a reported price, 12-foot swim spas run $24,599 to $47,695:

• Bullfrog Spas: $37,895 to $47,695 · Swim Series starting prices (MSRP), 1 of 1 model
• Endless Pools: $26,499 to $27,999 · Maker's list price (MSRP), 2 of 2 models
• LPI: $24,599 to $33,899 · Maker's list price (MSRP), 9 of 11 models
• Master Spas: $25,499 to $31,499 · Reported price, 3 of 4 models
• Wellis: $25,999 to $28,999 · Maker's list price (MSRP), 2 of 2 models

The other brands quote through dealers. The pad, delivery and the electrical work come on top; what a swim spa costs covers those with sources.

32 of the 37 that publish a breaker size need a 50 or 60 A circuit. Five list 30 or 40 A. Every one here runs on a single circuit.

A licensed electrician sizes the circuit for your panel and the length of the run. The amps and circuits for every model are on swim spa electrical requirements.

About $46 a month for the typical one here, just holding temperature with the cover on, and $22 to $62 across the 16 with a California listing. Swimming and colder weather add to it.

The guide to swim spa running costs explains what drives it.

None. The shortest dual-temperature swim spa we track is the Artesian Spas TidalFit DTL-6, at 14′. Every one is listed on swim spas with a hot tub side.