How to light a wood-fired hot tub: a simple step-by-step guide

A wood-fired hot tub is one of the great pleasures of a country stay, and lighting one is simpler than it looks. The good news for guests is that most of the hard part is already handled: at almost every stay we list, the tub is cleaned and filled with fresh water before you arrive, so your only job is the fire. This guide walks through how to get a wood-fired tub from cold to a steaming soak, what to expect on timing and the few questions worth asking your host before you go.

Before you arrive: ask about heating and wood

Two quick questions save a lot of waiting. First, ask whether the host can start heating the tub before you arrive. Because a wood-fired tub takes a few hours to come up to temperature, many hosts are happy to light it so it is hot the moment you walk in. Some do this for free as part of the welcome, others charge a small nominal fee and it is well worth it after a long drive. Second, ask how firewood works. It varies from place to place: some hosts include all the wood you need, some leave one or two complimentary bags to get you started, some sell extra bundles on site and a few ask you to bring your own. Knowing which it is means you arrive with enough to see the evening through.

The one rule that matters: water first, fire second

If you remember nothing else, remember this. Never light the fire unless the tub is full and the water comfortably covers the submerged stove or firebox. Lighting a dry or low tub will warp the metal and ruin the heater, and it is the single mistake every host warns against. Since the tub will already be filled for you, this usually just means a quick look to confirm the water level before you strike a match.

Lighting the fire, step by step

Start by skimming any leaves off the water with the net provided and clearing old ash out of the firebox so the air can move. Build the fire small and let it grow: crumpled paper or a firelighter at the bottom near the chimney, a handful of dry kindling on top, then a couple of small logs once it has caught. Use dry, seasoned wood and resist the urge to cram the firebox full. A steady, well-fed fire heats faster and cleaner than a smothered one. Expect to get through a fair amount of wood, often two or three bundles for a heat from cold.

How long it takes, and keeping it going

Plan on roughly two to four hours from cold to soaking temperature, and a little longer on a cold winter evening. Keep the fire alive by topping it up before the flames die down, adding a log every twenty to thirty minutes rather than letting it burn out and starting again. Two small habits make a real difference: leave the insulated lid on while the tub heats so it traps the warmth, and give the water a stir with the paddle now and then, because the hot water rises to the top while the bottom stays cooler than the thermometer suggests.

Getting the temperature right

Aim for around 38 to 40°C, which is the sweet spot for a long, comfortable soak and treat 40°C as the maximum. As you get close, stop feeding the fire so the water settles rather than overshoots. If it does run too hot, simply top it up with cold water from the hose and stir it through. From there you control the temperature with the size of the fire: a small flame holds it steady, no flame lets it drift down.

Putting it out, and a note on safety

When you are done, let the fire burn down rather than dousing a hot firebox with water, close the air vent to starve it and let the stove cool fully before anyone drains the tub. Never leave a lit fire unattended, and keep children well clear of the firebox, chimney and stovepipe, which stay searingly hot long after the flames are gone. Many wood-fired tubs run without chemicals, so they are simply drained and refilled between guests rather than chlorinated, which is part of why the water feels so soft.

The last trick is timing. Work backwards from when you want to be in the water: light the fire three to four hours ahead and you will be sinking in just as the sky turns. Some of our most loved wood-fired soaks make it easy, from The Farmhouse at Porcupine Hills high in the Overberg hills to Radio Nowhere Cabin out in the fynbos, Aloe Cottage at Bokrivier on its open farmland and Montana Vista at Gecko Rock deep in the Karoo. Light it early, pour a glass of something and let the evening come to you.