Side-by-side reference

Sauna vs cold plunge vs hot tub.

Similar backyard real estate. Very different infrastructure, maintenance and energy profiles.

Planning factor	Sauna	Cold plunge	Hot tub
Typical footprint	18–60+ sq ft	10–20 sq ft	35–65+ sq ft
Electrical	120V or 240V depending on type/model	Often 120V; larger chillers vary	Often 240V; some plug-and-play models use 120V
Water	None for infrared; traditional sauna may use small amounts on stones where permitted	Filled basin + filtration/sanitation system	Large heated water volume + filtration/sanitation
Drainage planning	Depends on model/site	Important	Important
Energy pattern	High draw, short sessions	Lower continuous/periodic chilling load	Continuous heat retention + pumps
Maintenance pattern	Generally low to moderate	Water quality + filters + chiller maintenance	Water chemistry + filters + pumps + cover
Best space efficiency	Infrared cabin	Vertical/barrel plunge	Compact 2–3 person spa
Where to research models	Sauna buying sources	Cold-plunge buying sources	Use manufacturer and dealer specifications

Choose heat when

Infrared cabins can be compact and some run on 120V. Larger traditional saunas usually require more electrical and site planning.

Choose cold when

A plunge can fit where a hot tub cannot, but water handling, sanitation, drainage and chiller ventilation still matter.

Choose soaking when

Hot tubs often consume the most area and usually demand the most continuous water and energy management.

Have actual dimensions?

Put them into the project brief and get a first-pass recommendation.