Having a wood-fired hot tub at home offers many powerful benefits, especially relaxation, pleasure, fun and socialising. But to reap all of this year-round enjoyment, some hot tub maintenance and ongoing costs are required.
Take a wild guess as to the annual expense of maintaining a wood-fired hot tub in your garden. Is the figure in your head around 100 quid, or are you thinking several times more than that perhaps?
In this guide, we provide a checklist of the tasks you need to manage to keep your hot tub in prime condition and propose the estimated costs that these maintenance tasks will require from you.
What maintenance tasks need to be done to care for your hot tub?
Starting off, let’s first define what we mean by the term ‘maintenance’ since we won’t be discussing operating costs in this article. Instead, we will discuss how to keep your hot tub’s exterior and interior, the systems for water heating, filtration and spa in good condition.
When hot tub maintenance is performed effectively, you can get the maximum lifespan out of your wood-fired hot tub, which manufacturers indicate is around 5-8 years, or even longer if you keep your unit in tip-top condition.
Exterior: Preserving the wood, cleaning the cover, polishing the steel parts
Interior: Cleaning the liner, maintaining the moisture level (for all-wood models)
Water heating & filtration systems: Cleaning or replacing the filters, flushing the water chamber of the heater, sweeping the firebox and chimney
Spa systems: Cleaning the plumbing
Let’s now explain each task and provide estimated costs.
Exterior
1. Preserving the wood – The wooden exterior, as well as any wooden accessories, of your hot tub must be treated with natural oil or special wood stain for outdoor use to protect the surface against dirt, moisture, UV damage and dehydration. Staining the wood also preserves and emphasises the natural wood look. With thermowood, red cedar or oak, this treatment process can be undertaken once a year, while some types of timber, such as spruce and larch, may need treating twice a year, both before and after the winter season. Check with your manufacturer for specific recommendations based on the type of wood used in your hot tub. Thermowood and cedar are types of wood that do not need any treatment at all, as long as you’re fine with the wood taking on a greyish colour as it naturally ages.
Taking an average hot tub that has a 2-metre diameter and 1-metre height, you will typically need to treat a surface area of 12.6m2. This will require approximately 0.5 litres of wood stain. Prices vary from around £6 to £17 per litre of stain, which depends greatly on the product and size of the package (for instance, a 5-litre tank will always be significantly less expensive than five 1-litre bottles of the same product). The estimated average price to treat the exterior once a year is £6 to £17.
WARNING: Do not apply paint, varnish or oils to the interior of the wooden hot tub because this will block water absorption, causing the hot tub to shrink and leak due to a lack of moisture.
2. Cleaning the cover – The hot tub cover must be cleaned monthly to avoid buildup of bacteria. While a wooden or plastic cover only needs a scrub with detergent and a good rinse, an insulated faux leather cover requires regular cleaning with any detergent. It is also recommended for the insulated faux leather cover to use leather/saddle soap and treat it with a faux leather conditioner with UV protection twice a year to ensure it remains durable and attractive. Saddle soap may cost between £5 to £10, plus around £15 for a bottle of conditioner, but you will use these numerous times throughout the life span of your hot tub, so this can be rounded down to approximately £7 to £10 per year.
3. Polishing the steel parts – Tightening bands, heater, heater wall, hearth plate, chimney and other parts of your hot tub need soft polishing to keep them glossy and clean of any dirt, water residue, soot or other matter. Use a gentle non-chlorine detergent and a non-abrasive cloth. Some manufacturers advise treating the metal parts of a hot tub with paraffin oil twice a year.
Interior
1. Cleaning the liner – Every time after draining the water, immediately rinse and wipe off any dirt or sediment from the liner. If you allow the liner to dry, it will require more effort and cleaning products to get the job done, so it is best to do it while the liner is still wet. Product-wise, you don’t need anything fancy. A regular non-abrasive bathroom cleaning spray works wonders, and only costs around £3 to serve you for a whole year (depending on your usage). Avoid products with chlorine if your hot tub has a fibreglass liner.
2. Maintaining the moisture level – Only for all-wood models. To ensure your hot tub does not leak, the wood needs to be allowed to swell naturally when it is in contact with water. If you leave the tub drained for a long time, be prepared to lose some water upon refilling it as a result of the cracks that will naturally form due to the wood shrinking when dry. It is important to note that all-wood hot tubs are not designed to be left unused for long periods. There are no set costs for this maintenance, unless you leave the hot tub empty and need to fill it with water just to keep it in good condition. If you are a regular hot tub user, you are unlikely to encounter issues.
Note: All-wood hot tubs need to be emptied in freezing temperatures, as frozen water can cause serious damage.
Water heating & filtration systems
1. Cleaning or replacing the filters – Most wood-fired hot tubs have a cartridge or sand filter, each of which requires slightly different maintenance. With a cartridge filter, you’ll need to replace the cartridge every 2–3 weeks, as per the manufacturers’ recommendations for your specific model. You can extend that time by checking the cartridge every week and flushing it with water, which, in normal conditions, may mean that a single cartridge lasts a month. With sand filters, the advice is generally to use filter balls which need to be manually washed every 3 months and replaced every 2 years. Sand needs regular backwashing, and must be replaced every 5 years. The annual cost of water filtration is typically under £60 (12 replacements for intensive year-round use) with a cartridge filter, around £10 with filter balls and under £5 with a sand filter.
2. Flushing the water chamber in the heater – Make sure to flush the water through the heating holes in the hot tub every time before you fill the tub with new water.The amount of water required is minimal, just a stream of water, so any cost is negligble.
3. Sweeping the chimney and firebox – This maintenance task needs to be performed every 20 uses on average. However, if you see soot building up, which can happen when you use a lot of resinous firewood for heating the water, or you observe the fire and notice a yellow flame with dark smoke, you should clean the firebox immediately. This task takes some time to complete, and there will be the initial upfront cost of purchasing the required tools for approximately £25. Tools are a one-off investment that you can use for several years. However, if you decide to hire a chimney sweep twice a year to complete the task for you, you can expect to pay around £60 on average per visit (but this varies depending on location and service costs). By the way, to ease the chimney sweeping, you can use creosote sweeping log. This product makes the soot buildup dryer and easier to clean. You can buy it for around £5 on Amazon.
Spa systems
1. Cleaning the plumbing – You will need to buy a special cleaner to flush the pipework of the hydro massage system if your hot tub has this component. Over time, biofilm (or gunk, as you might call it) forms in the pipework of the hydro massage system causing two major problems: It reduces massage efficiency (as the pipe diameter is reduced or clogged) and/or it causes the bacteria to circulate throughout the hot tub which reduces disinfection efficiency and degrades the water quality. As a rule of thumb, you should flush the plumbing every time you drain the water, or at least once every 3 months. Some branded products can cost around £20 for two treatments, while other options average out at £2 per treatment, so 4 flushes per year may cost around £24.
Totals
The maintenance costs of a wood-fired hot tub depend largely on its configuration. Don’t be discouraged from adding a range of accessories to your hot tub, however, simply because they increase your overall maintenance costs. An accessory such as insulated faux leather may cost an additional £7 per year in maintenance, but it will also highly reduce the water heating time, so the benefits are well worth the minor investment. If you add on a UV lamp, for example, it will cost you £XX per year, yet reduce the amount of water disinfectant needed which in turn saves you money. As you can see, it is possible to save pounds by spending pennies when you add accessories to your hot tub, as well as improve your hob tub experience.
Think back to the earlier number in your head, and let’s see if your initial guess as to annual maintenance costs was correct.
If you choose a wood-fired hot tub with a thermowood exterior, insulated cover, sand filter (with filter balls), hydro massage system and if you sweep the chimney yourself, you’re likely to spend approximately £64–110 a year on maintenance (the range is calculated when using the lowest price maintenance products and the most expensive ones).
Less expensive maintenance, such as for an all-wood off-the-grid hot tub, can be estimated at around £38–57 per year.
Before purchasing a hot tub, it is advisable to add and remove the systems or items that you think are necessary or otherwise to check your estimated ongoing spend once you have it in your garden. Regardless of the type of hot tub model you choose, the numbers are unlikely to be daunting, as hot tub maintenance is generally an affordable expense.
Bubbling best wishes to all in maintaining your hot tub for maximum enjoyment!
