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Wood-fired vs electric hot tub

Wood-fired tubs are heated from cold for each use in a few hours and cost firewood; insulated electric spas stay at temperature all week and cost electricity. Insulation, the cover and how often you change the water decide the bill.

Updated Oct 17, 2026

Side by side (model, ≈ 1,500 L, 5 °C outside)

Wood-fired (fibreglass-lined, wooden lid)Electric spa (full foam, thermal cover)
Heat-up from 10 °C≈ 2 h with a 25 kW stove≈ 16–17 h with a 3 kW heater
Kept warm between usesUsually not (heat loss ≈ 600 W at 38 °C)Yes (≈ 100 W through shell and cover)
Weekly energy≈ 34 kg firewood for 2 uses; ≈ 57 kg for 4≈ 37 kWh electricity for 4 uses incl. pump
WaterChanged every few days (no or simple filtration)Filtered and treated, changed every few months
InstallationLevel base, chimney clearances, no electrician for the tub itselfDedicated circuit (UK: 13 A plug-in or 32 A; US: 240 V 40–50 A)

Which one?

Wood-fired tubs suit weekend and holiday use, off-grid places and people who enjoy the fire. Electric spas suit daily use and people who want hot water at the push of a button.

Questions and answers

How long does a wood-fired hot tub take to heat?

Typically 2–4 hours for 1,000–2,000 L, depending on the stove's output, the starting water temperature, the lid and the weather.

Are wood-fired hot tubs cheaper to run?

Per use often yes if you have cheap firewood, but they are usually heated from cold each time and the water is changed more often. For daily use an insulated electric spa is usually cheaper and easier.

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