What wood do you need to heat a hot tub?

You have a hot tub in the garden or are thinking about getting one. A wonderful idea. But before you sink into that steaming water under the starry sky, there’s one important point you can't ignore: the fire must be lit first. And not just with some wood that happens to be at the bottom of the garden shed. No, for a well-heated hot tub, the right wood is crucial.

Perhaps you think: wood is wood. But just like with wine and cheese, there's more nuance to it than you might expect. Don't worry, you don't have to become a timber merchant to see the wood for the trees. In this blog, you'll read exactly what wood you need for your hot tub, what you should avoid, and how to handle storage and burning smartly.

Why the right wood is important for your hot tub experience

You might know the feeling: you throw some wood into the stove, light it, and wait patiently. But the water remains lukewarm, the smoke stings your eyes, and the neighbours ask if something is on fire. Not exactly the start of a relaxing evening.

The cause? Poor wood choice. The type of wood determines how quickly, evenly, and cleanly your hot tub heats up. Good wood ensures a beautiful flame, little smoke, long-lasting heat, and a clean flue. Bad wood, on the other hand, smokes, crackles, leaves residue in the stove, and takes forever to get hot.

And if you choose the right kind, you'll have to refill less often during your hot tub evening, which is nice when you're just relaxing and don't feel like hauling logs.

Did you know that Happy Timber not only designs and produces hot tubs but also outdoor saunas? Everything for a complete wellness experience, right at home.

Hardwood versus softwood: what's the difference?

For firewood, we roughly distinguish between hardwood and softwood. The difference is not only in how heavy it is but mainly in how it burns.

Hardwood, such as oak, beech, or ash, comes from deciduous trees. It burns slowly, emits a lot of heat, and leaves less mess in your stove. Ideal for a hot tub.

Softwood, such as spruce or pine, comes from coniferous trees. This wood burns quickly and hot, but is often resinous and causes more smoke and soot. Moreover, it burns up so fast that you constantly have to refill wood to maintain the temperature. Not exactly practical when you're just leaning back and relaxing.

In short: for the hot tub, preferably choose a good hardwood species. And ideally, one that is well-dried, so it burns well immediately.

What types of wood are suitable for your hot tub?

Let's calmly go through the most popular wood types. Not in a list, but in plain language.

Oak wood: Oak wood is perhaps the best-known hardwood. It is heavy, strong, and burns long and evenly. This makes it extremely suitable for prolonged burning, such as in a hot tub. The heat output is high and stable. However, it is important that oak wood is well-dried. If it is still too wet, it can contain acid that releases extra smoke or odour. Dry oak wood, on the other hand, burns beautifully and keeps your water warm for hours.

Beech wood: Beech wood is also an excellent choice. It has the property of igniting quickly, so you don't have to wait endlessly for the fire to get going. At the same time, it burns relatively long and clean. A nice middle ground for those who value both speed and warmth. Many hot tub users swear by beech wood because of its pleasant smell and calm combustion.

Ash wood: Ash wood is often referred to as the all-rounder among firewood. It dries relatively quickly, is easy to burn, and hardly splatters. Even if it's slightly less dry, it still does its job perfectly. It gives off a lot of heat and is pleasant to use, making it suitable for beginners too.

Birch wood: Birch wood burns up somewhat faster than the other hardwoods but has another advantage: it looks beautiful, smells fresh, and is easy to light. The white bark creates a crackling fire that gets going quickly. You could use it to start your fire, and then switch to oak or ash for the long haul.

Wood types you should avoid

Perhaps there's a pile of wood in your shed, from an old job or that fence you once broke down. It's tempting to just try it. However, it's wise to pay close attention to what you throw into your stove.

For instance, it's better not to use softwood. Pine or spruce might seem appealing due to their fast burning, but they are full of resin. That causes a lot of smoke, pollutes your flue, and can cause damage to your stove in the long term. Not ideal.

Also, impregnated, painted, or glued wood is a no-go. These contain substances that are released during combustion and are harmful to both humans and the environment. And your hot tub is ultimately meant to be a place for relaxation, not for chemical experiments.

Also, be careful with damp or mouldy wood. If the wood smells musty, is dark brown, or feels like a sponge, it's far from ready for use. You can recognize dry wood by a hollow sound when you tap two blocks together, slight cracks in the surface, and a low odour intensity.

How much wood do you actually need?

That, of course, depends on the size of your hot tub and the outside temperature. But on average, you can say: a 1500-litre hot tub heats up in about 2.5 to 3 hours with approximately 2 to 3 wheelbarrows of good, dry wood.

Don't burn everything at once, but add in phases. Start with small blocks or kindling, and slowly build up the fire. Once the fire is burning steadily, you can switch to larger blocks for long-lasting heat. Once you've reached a constant temperature, you often only need to refill occasionally.

A small advantage of experience: after a few times, you'll know exactly how much wood you need for your favourite temperature. And that saves hassle on cosy evenings.

Storing wood: how to keep your supply usable

You've found the perfect wood. Now for a good place to store it. It's best to store wood in a dry, well-ventilated place. Don't put it directly on the ground, but use a pallet or rack so that air can circulate underneath. An open shed or lean-to is ideal: sheltered from rain, but still with sufficient air circulation.

If necessary, cover the wood with a tarpaulin, but make sure there is space at the sides for ventilation. Completely wrapping it is a recipe for mould. Also, maintain a kind of rotation system: use the oldest wood first, and always let new supplies dry for another season.

Extra atmosphere: scented wood For those who want to enrich their hot tub experience with something extra: some types of wood release a subtle scent during burning. Think of cherry wood or apple wood. Not intended to heat the entire hot tub, as they are too rare and burn too quickly, but adding a handful to the fire creates a soft scent that makes your evening just that little bit more special.

Please note: this refers to pure wood, not perfumed kindling. Keep it natural.

Don't feel like chopping yourself?

Sometimes time or inclination is lacking. And not everyone has a splitting axe and a pile of tree trunks behind their house. Fortunately, you can turn to numerous suppliers for custom firewood: split, cut to length, and neatly packaged. Always ask about the moisture percentage; it should be below 20%, preferably around 15%.

Make sure you choose wood that suits your usage rhythm. Do you use the hot tub weekly? Then a larger supply is handy. Is it more of a luxury for weekends? Then a small pile will suffice. Either way: with good wood, relaxation begins even when lighting it.

Would you like advice on using wood for your own hot tub, or do you have questions about the maintenance of your stove? Feel free to contact us or request a non-binding quote – you will receive a response within one working day.

 

Frequently asked questions about wood for the hot tub

Can I use pallets or waste wood for the hot tub?

It's better not to. Pallets are often treated with glue or chemicals. These substances are released during combustion and can be harmful.

How long should wood dry before use?

Depending on the type: on average 1 to 2 years. Oak wood, for example, needs longer than birch. Air circulation is important here.

How do I know if wood is dry enough?

Dry wood is lightweight, sounds hollow, and has cracks in the ends. For certainty, you can use a moisture meter.

How do I heat my hot tub fastest?

Use dry kindling to build the fire, then add larger blocks. Make sure the air supply is wide open during startup.

Can I leave wood outside in the summer?

Yes, as long as it's under a shelter and not on the ground. Ensure ventilation and cover the top if necessary against rain.