When you buy a wood-fired hot tub, you look at the wood, the colour, the size. But the part that quietly decides how much wood you burn and how long you wait for a warm soak is the one you never see: the stove.
There are two main types — single-chamber and dual-chamber — and the difference comes down to one simple idea: how long the fire's heat stays trapped inside the stove before it escapes up the chimney. Let's look at it with a couple of pictures.
Here's the neat part: there's no pump and no electricity involved in heating the water. It runs on a simple rule of nature — warm water floats up, cold water sinks down.
Cold water drops into the stove at the bottom. The fire warms it. The warm water rises back up into the tub, and the next bit of cold water sinks down to take its place. This little loop keeps going on its own, as long as the fire is burning.
The water moves itself in a loop — warm rises out to you, cold sinks back to the fire. No pump, no electricity for the heating.
So the stove's whole job is simple: grab as much heat from the fire as it can and pass it into the water — before that heat escapes up the chimney and vanishes. And the trick to doing that well is keeping the hot smoke inside longer. That's the entire difference between the two stove types.
When wood burns, the fire makes hot smoke — and that smoke is full of heat. The longer that hot smoke stays inside the stove, wrapped in water, the more of its heat it hands over to your tub before it leaves. So the question is simply: how long a route does the smoke take to reach the chimney?
A single-chamber stove takes the short way — the smoke goes almost straight up and out. A dual-chamber stove, like Bauqua's, folds the path so the smoke travels roughly twice as far inside first, giving up much more of its heat on the way.
Single-Chamber
short, straight path
Dual-Chamber BAUQUA
longer, folded path
The orange dotted line is the route the hot smoke takes, drawn to match Bauqua’s actual stove layout. A single-chamber stove sends it almost straight up and out; Bauqua folds it across, down and back up so the heat travels about twice as far — wrapped in water the whole way — before it escapes. (Bars are illustrative.)
The fire is enclosed and the hot smoke heads almost straight up and out the chimney. Simple and it works — but the heat spends very little time inside, so a good chunk of it leaves before the water can grab it. In plain terms: some of the wood you paid for ends up warming the sky.
Bauqua's stove keeps the fire fully enclosed, then routes the hot smoke up, across the top, then down and back up before it reaches the side chimney — roughly twice the distance of a single-chamber stove. Because the heat travels farther, surrounded by water the whole way, much more of it ends up in your tub.
Same fire, same wood — Bauqua's stove just gives the heat a longer route through the water before it can escape.
The design is only interesting because of what you notice at home. A longer heat path mainly affects four everyday things:
The stove isn't magic. How fast your tub heats and how much wood it eats also depends on dry wood, a good insulated lid, how well the tub holds heat, and the weather. A longer heat path gives you a better starting point — the rest is down to how you use it.
When you compare hot tubs, don't stop at "wood stove included." Ask about the stove itself — it works hardest and lasts longest (or fails first). Four quick things:
We build a dual-chamber stove: the fire is fully enclosed and the hot smoke is routed through a longer, folded path before it exits — so more of the fire's heat ends up in your water and less escapes up the chimney. It's made from the rust-resistant AISI 316 steel with cast-iron doors, for exactly the reasons above. You can see how each model is built on our hot tubs page.
Not sure which model suits your space and how you'd use it? We're happy to talk it through.
Talk to our team →Yes, usually — and it’s worth understanding why, because it’s the same reason it also heats a little faster. The fire itself isn’t doing anything different. But instead of the hot smoke rushing straight up the chimney, the dual-chamber design sends it on a longer, folded path — so it stays inside, wrapped in water, long enough to hand over most of its heat before it escapes. More heat captured from each log means you don’t have to feed the fire as often to reach and hold your soaking temperature. Over a single soak the saving is modest; over a full season of regular use it adds up to noticeably less firewood. How much exactly also depends on things you control: dry hardwood burns hotter and cleaner than damp or soft wood, and a well-insulated tub with the lid on while heating loses far less warmth to the air.
Usually a little, yes — and for the same reason it uses less wood. Because more of the fire’s heat ends up in the water instead of disappearing up the chimney, the water reaches soaking temperature sooner. To be clear, the fire isn’t hotter and it isn’t a dramatic difference — you’re simply wasting less of it. As a reference point, a Bauqua Amber 200 goes from cold to about 39 °C in roughly 2–2.5 hours, and the larger Amber 225 in about 3–3.5 hours. Your own times will shift with a few things: how much water the tub holds (a bigger tub takes longer), how cold the water and the air are to begin with (winter takes longer), how dry your wood is, and whether you keep the insulated lid on while it heats — which makes a real difference.
From the outside you often can’t — both types have a fire door and a chimney and can look identical, so it’s easy for a cheaper single-chamber stove to be sold without the difference ever being mentioned. The fix is to ask the seller two direct questions: is the stove single- or dual-chamber, and what grade of stainless steel is it (the common AISI 304, or the tougher, more rust-resistant AISI 316)? While you’re at it, ask whether the full chimney kit — heat shield, extension and rain cap — is included. A good manufacturer will answer all three plainly and quickly. If you get a vague reply, a change of subject, or just “it’s high quality” with no specifics, treat that as an answer in itself.
No — day to day it’s exactly the same. You light it the same way, and the main upkeep is simply removing the ash regularly and keeping it clean, just like any wood stove. There’s no pump, no heating element and no electronics on the heating side to service or break. The only small extra is that, now and then, it’s worth checking that no ash or soot has built up in the folded path so the smoke keeps flowing freely — an occasional look, not a chore, and your tub’s manual will show you how.
We're a small team and genuinely happy to help you pick the right model for your garden, your usage and your budget. We usually reply within a few hours.
Erzähl uns von deinen Plänen und wir erstellen eine persönliche Empfehlung.
Wir antworten in der Regel innerhalb von 24 Stunden.
Erzähl uns von deinen Plänen, und wir erstellen eine persönliche Empfehlung.
Wir antworten in der Regel innerhalb von 24 Stunden.
Tell us about your plans and we will prepare a personalised recommendation.
We typically respond within 24 hours.
Tell us about your plans and we will prepare a personalised recommendation.
We typically respond within 24 hours.
