There's a particular kind of luxury in a wood-fired hot tub. No pumps humming, no electricity bill climbing, no app to open — just the crackle of a fire, steam rising into cold air, and water heated the way it has been for centuries. As backyard wellness setups grow, the wood-burning hot tub has become the centerpiece many people didn't know they wanted.
But they work differently from a conventional spa, and choosing one means understanding a few things first. This guide covers the types, how the heating works, what to look for, and which models are worth considering.
What Is a Wood-Fired Hot Tub?
A wood-fired hot tub is exactly what it sounds like: a soaking tub heated by a wood-burning stove rather than an electric or gas heater. The stove — either submerged inside the tub or mounted externally — transfers heat directly to the water as the fire burns. There are no pumps or heaters drawing power, which is what gives these tubs their signature off-grid appeal.
The experience is different from a jetted spa. It's about the quiet ritual of lighting a fire and easing into naturally heated water, often surrounded by nature. Browse the full range in the wood-fired hot tub collection.
How the Heating Works
There are two main stove configurations, and the difference matters.
Internal (submerged) stoves sit inside the tub, in direct contact with the water. This is the most efficient and fastest-heating arrangement because there's no heat lost in transfer — but the stove takes up some space inside the tub. A well-designed internal stove can heat several hundred gallons in under two hours.
External stoves sit outside the tub and circulate water through the heater via thermosiphon (hot water rises, cool water sinks, creating natural flow). This keeps the full interior free for bathers and separates the fire from where you sit, at the cost of slightly slower heat-up.
Either way, expect a heat-up time measured in hours rather than minutes — this is a plan-ahead pleasure, not an on-demand one. The best modern stoves, like those built from 304 stainless steel with secondary combustion chambers, dramatically improve efficiency and reduce how much wood you burn.
Materials: Why Wood Choice Matters
Traditionally, wood-fired tubs were made from cedar, prized for its natural rot resistance and aroma. Today, thermally-treated woods have become the premium choice. Thermo-Spruce, for example, is organically heat-treated to be more stable and decay-resistant — some manufacturers state it lasts up to twice as long as cedar in outdoor conditions.
Inside, many modern tubs use a contoured fiberglass lining. This is a genuine upgrade: it's comfortable, hygienic, easy to clean, and it protects the wood from constant water contact. The wood then serves as the beautiful, durable exterior shell. It's the best of both worlds.
What to Look For
A few factors separate a great wood-fired tub from a frustrating one.
Heat-up speed. Look at how quickly the stove heats the stated volume. A tub that takes all afternoon to warm up will get used far less than one ready in under two hours.
Capacity. Match the size to how you'll use it — an intimate two-person soak or a six-person social centerpiece.
Stove quality. Stainless steel construction and features like a secondary combustion chamber mean better efficiency and less wood consumption.
What's included. The best tubs arrive with the essentials — steps, an insulated cover, drainage, and the full chimney kit. A good insulated cover is especially important; it holds heat between sessions and dramatically improves efficiency.
Two Wood-Fired Hot Tubs Worth Considering
Here are the two standout options, both from SaunaLife's SOAK-Series, which pairs Thermo-Spruce shells with fast, efficient stainless stoves. Each links through to full specifications.
SaunaLife SOAK-Series Model S4N Wood-Fired Hot Tub — 6 Person
The natural-finish S4 holds over 304 gallons and heats from 40°F to 95°F in roughly 1.5–2 hours via its efficient 304 stainless steel stove — among the fastest available. Arrives fully assembled with steps, insulated cover, drainage, and chimney kit.
Prefer a bolder, modern look? The same tub comes in a striking black-fiberglass finish.
SaunaLife SOAK-Series Model S4B Wood-Fired Hot Tub — Black, 6 Person
The same fast-heating, fully-assembled S4 with a dark grey contoured fiberglass lining and black-accented finish for a contemporary backyard aesthetic. Thermo-Spruce exterior, 304-gallon capacity, and the same self-cleaning stove efficiency.
Placement, Care and Safety
Site your wood-fired tub on a level, fire-safe base — gravel, pavers, or concrete — with clearance around the stove and chimney, and away from overhanging branches or structures. Because there's an open fire and hot flue involved, keep that clearance generous and never leave the fire unattended around children.
Maintenance is refreshingly simple. Drain and refill periodically, wipe down the fiberglass lining (much easier than scrubbing bare wood), keep the insulated cover on between uses to retain heat, and clear ash from the stove after it cools. With thermally-treated wood and a fiberglass interior, upkeep is minimal.
Want to build out the full hot-and-cold experience? Pair your tub with a sauna and even a cold plunge — our guide on combining hot and cold therapy explains how it all works together.
Frequently Asked Questions
How long does a wood-fired hot tub take to heat up?
It depends on the stove and water volume, but an efficient model can heat several hundred gallons in roughly 1.5 to 2 hours. Larger tubs or external stoves take longer.
Are wood-fired hot tubs hard to maintain?
Not particularly. Models with a fiberglass lining are easy to wipe clean, and thermally-treated wood exteriors need little care. The main routine is draining and refilling periodically and clearing ash from the stove.
Do wood-fired hot tubs need electricity?
No — that's their main appeal. The wood stove heats the water with no power required, making them ideal for off-grid and remote locations. Some owners add an optional pump or filter, but the core tub runs on fire alone.
How many people fit in a wood-fired hot tub?
It varies by model. Popular family-sized tubs like the SaunaLife S4 comfortably seat up to six, while smaller designs suit two to four.
The Bottom Line
A wood-fired hot tub offers something an electric spa can't: a genuine, off-grid soaking ritual with the warmth and character of a real fire. Focus on a fast, efficient stainless stove, durable thermally-treated wood, and a comfortable, easy-clean lining, and you'll have a backyard centerpiece that lasts for years. Explore the current models in the wood-fired hot tub collection and start planning your soak.