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The thought of an outdoor sauna is just too good to be passed. No wonder many homeowners are now adding a hot tub to their gardens.
Those hosting garden parties would love a good hot tub, more so, if your guests would love to toast while soaking in. Additionally, if you have no much square footage and the budget to install a swimming pool, then a hot tub would be the next best option.
While an outdoor shower is great for summer, a hot tub is even better, both for summer and winter. Call it a warm oasis in the comfort of your outdoors that is clearly not as far-fetched an idea as one might think.
A popular type is the wood-fired hot tub but you may be asking: are they worth it?
Adding a wood-fired hot tub to your deck or backyard is a sure way to elevate your outdoor space to a whole new level, and transform your evenings into blissful relaxation.
Whether spring is in bloom, or you want to stay warm up on cold winter nights, it couldn’t be a better time to take the plunge and invest in a beautiful wood-fired hot tub. More so, it blends effortlessly into nature!
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What is a Wood-Fired Hot Tub?
Essentially, a wood-fired hot tub burns wood to create a fire in the bottom of the stove that heats up water in the tub to a desirable temperature so you can enjoy a warm soak.
While you can build a wood-fired tub, we recommend purchasing one that is ready to go.
The great thing about most hot tubs is that they come fully assembled and as soon as they are in situ and the parts connected together, they are ready to use. Just use your manufacturer’s installation guide for further information.
A complete wood-fired hot tub package will include the tub, a drain with a shut-off valve, a submersible/external marine-grade aluminum/stainless steel wood stove, seating benches, a stainless steel stove pipe, and rain hat, a long-handled ash scoop, a thermal/ insulated lid and sometimes, a floating thermometer.
However, you can always add other hot tub accessories.
Depending on the size of your tub, it can fit between 2 to 10 people(most hot tubs are of such capacity). But there are very large hot tubs that even have a 30-person(s) capacity.
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Cedarwood reigns supreme as the best type of wood for a wood-fired hot tub due to its high tannin content, which makes it naturally waterproof and prevents decay and wood rot.
Where Should You Install a Wood-fired Tub?
Hot tubs are a great addition to backyards and decks, and there’s nothing like a nighttime soak in your outdoor wood-fired hot tub while gazing up at the stars.
The key is to ensure you sit your tub on a site with a firm, clear and level ground, ideally, on a platform to ensure your tub is not in direct contact with the ground and to prevent grass from growing under the hot tub.
This can be on purpose-built decking, hard standing such as concrete and packed earth, or even a ground covered with flagstones.
The space should also be large enough that even with the tub in place, you have easy access all the way around. This will make cleaning and future maintenance much easier.
If the tub has an external heater, usually sitting up to 1 meter away from the tub, allow for more space to ensure safety and minimize the risk of accidental contact and injury while maintaining access.
If it has an internal heater or an integrated heater, position the tub so that there is easy access for loading the stove, and emptying the ash every now and again.
Pay attention to the position of the heater as it will determine the position of the chimney. Point the flue away from windows to ensure smoke does not block the opening of a window!
How Does a Wood-Fired Hot Tub Work?
The operation of a wood-fired tub is very simple.
You need to start by filling the tub to the marked line with water so that water covers the firebox. Once the tub is filled with water, open the firebox by lifting its cover using its handle.
Check how much ash is in the firebox. It is important to make sure that ash isn’t blocking the bottom of the air intake (the pipe with a swiveling lid).
A small amount of dry ash is fine and can be used as a base for lighting the fire but if it is excessive, then clear some or all with a scoop. If there is wet ash and water (as rain can get in through the chimney), it is best to scoop it all out into a metal pail using a scoop.
Place a firelighter on the bottom of the firebox or on a bed of tightly twisted newspaper, and surround it with small pieces of kindling so that you can still reach it with a match. Once it is alight, add more kindling and gradually more dry logs.
When they are burning well you can then fill the firebox to the top with wood and replace the lid completely. You want to check the fire every 30 minutes and add wood as necessary to keep the firebox full.
As well, check the temperature of the water each time, stirring it because the surface is usually hotter than the bottom!
Once you have done this, close the swivel lid on the air intake. This will dampen the fire (although the temperature may still rise). Any time you open the firebox please sit the handle on the stone slab so as not to burn the decking.
After your bathing session, leave everything closed and do not drain the water.
How Long Does A Wood-fired Hot Tub Take To Heat?
A wood-fired hot tub allows you to warm up water with a wood-fired stove. No electricity, no pumps. This gives you the freedom to enjoy your hot tub even if you live in a remote area.
But how long does it take to fill the tub with water and heat it? Filling the tub and lighting the fire takes 5-8 hours and you will need to be around for much of this time.
On average, using no electricity, a wood-burning hot tub takes about 1-2 hours to heat the water in the summer, and 3-4 hours in the cold season to heat the tub water to the desired temperature of between 38° C to 40.6° C.
NOTE: The time it takes to heat the water will depend on the burner and the tub size, as well as the temperature of the water used to fill the tub and the outside weather conditions.
Also, before lighting the fire in the stove, ensure the tub is filled up to at least 50 mm above the upper connection pipes of the stove. Plus, never light the stove when the tub is empty or not full because heating a half-empty tub will cause melting of the stove.
You must not start emptying the tub before the fire and embers have burnt out completely.
Wood-fired hot tubs can either have an internal or external heater. External heaters are outside the tub allowing the tub to seat more people.
On the other hand, an internal heater consumes nearly 1/3 of the internal space requiring a much larger hot tub to fit the same number of persons as an external heater.
Is a Wood-fired Hot Tub Better Than An Electric One?
Wood-fired hot tubs are preferred to electric hot tubs because of their very low running costs.
A wood-fired tub is very inexpensive to operate in comparison to an electric tub because only dry firewood or logs will be enough to light it and the cost of wood is cheaper than the cost of electric energy.
An electric hot tub will, beyond a doubt, increase your electricity bills.
According to Jeff Campbell, an electric hot tub owner, it will take most electric hot tubs between 4-8 hours to reach the desired temperature, depending on the capacity of the tub, ambient air temperature, and the temperature of the water from the hose.
If using a 220v hot tub with a 4kw heater, and it takes 8-11 hours to heat, it will cost you more than using wood; even though such a heater is more powerful.
On the other hand, the firewood needed for a wood-fired hot tub may come from different sources and usually will cost substantially less than the electric power.
A wood-fired hot tub also heats the water considerably quicker than an electric one, because of the heat that burning wood also produces.
It’s a more sustainable option today that can be placed just anywhere, as long as the foundation is strong enough to hold them – in your backyard garden, beside your camper, or next to a woodland cabin or cottage country house.
Electric hot tubs, on the other hand, are constrained by their proximity to a power outlet and a qualified electrician will need to do his part of the work setting up your garden spa.
When you wish to use the tub, you simply fill it and heat the water; and when not in use, simply drain the water out, clean the bathing area and clean the ash out.
If you value the simplicity offered by a press of a button and you can wait longer to prepare your outdoor spa, however, then an electric hot tub might bring more benefits to you.
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Can You Use a Wood-fired Hot Tub In The Winter?
Yes, you can use your wood-fired hot tub in the winter.
Hot outdoor tubs are well-appreciated in Nordic culture and after a good winter sport like alpine skiing, a hot tub is a terrific way to relieve tired muscles.
However, some factors must be considered:
- The water will take longer to heat up to a considerable temperature because the starting temperature of the water, plus, the ambient air temperature is colder than in the summer.
- The water may freeze resulting in irreversible deformation of a wooden hot tub i.e.cracks, and shape deformity.
Thus, in winter you have to drain the water immediately after your soak. Also, leave the drain valves open during winter and dry water splashed around the wood-fired hot tub as it will freeze, and there is a danger of slipping.
- The entire tub may freeze solid and cause severe tub damage. Therefore, drain the tub after use and also, make sure there is no water left in various connections and hoses. Plus, do not forget to check for water residue in the heater.
If the hot tub has an air bubble massage system installed, also blow out residual water from the pipes and hoses of this system after draining the tub completely until all of the residual water runs out.
Covering your tub using an insulated lid also allows the water to keep its temperature for days before it would eventually freeze.
- The heater may freeze when turned off, especially if external. Usually, because there is no insulation on the heater and as such it will lose its heat energy quickly and could freeze.
To prevent the heater from freezing, Timberline Water Wood Stoves recommends:
- Completely putting out the fire after use.
- Isolating the heater from the tub with port plugs or gate valves and storing it away.
- Draining the heater.
You’ll need to spend a little more time checking your heater and feeding it wood if you want to use a wood-fired hot tub in the winter.
When the tub reaches operational temperature, maintain a low fire or a bed of coals going to keep the heater producing a minimum amount of heat.
This will be determined by the outside temperature as to how much of a fire you need. Generally, when it is colder outside, the hot tub will lose its heat quicker.
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How Do You Maintain A Wood-fired Hot Tub?
The wood-fired hot tub is meant for outdoor usage all year round., both in warm and cold weather; and with warm or cold water. But to make it last longer, proper maintenance is key.
Key things to do include:
1. Take a shower beforehand
A person who did not shower before entering will make the water significantly dirtier.
Sunscreen, cosmetics on the skin, and sand on the feet should not find their way into the hot tub. Therefore, shower before dipping in for a soak.
NOTE: Always enter and exit the hot tub slowly, as some surfaces may be slippery i.e. a plastic inner surface.
2. Use a thermal/ insulated cover
A hot tub loses nearly all of its heat from the top as hot water rises. In the winter, it loses even much more heat because of the freezing temperatures.
With a full insulated cover or thermal lid, you can leave the tub in the evening, and in the morning, the water temperature will still be warm enough to have a hot tub without restarting the fire.
3. Maintain the Water Level above the Water Heater
Always maintain the water level within inches above the stove to protect the water heater from being exposed and melting.
The problem arises when bathers overflow the hot tub (which happens often during parties).
More water must now be added before the final person(s) leaves the hot tub in order to bring the water level back to this level.
The bathers must remain in the tub until the operation is completed.
4. Clean Your Tub
Upon delivery, the hot tub may have collected dust so it is important to clean the surfaces of the bathing area before using it. Leave the bottom valve open and rinse the entire hot tub with water and finish by wiping the entire surface.
It is recommended to drain the hot tub and empty the water every 2-3 uses if used privately but if used by multiple people, then it is best to change it daily.
Even before using the tub for the first time, or before bathing, apply an anti-bacterial product, ideally, an active oxygen treatment to prevent bacteria and cloudy water.
This treatment will oxidize the water, breaking down organic matter like dead skin cells, perspiration, urine, and cosmetics.
After bathing, add some chlorine (of the same type as is used for swimming pools) to the water. This prevents algae growth and, to some extent, protects the wood from rot.
TIP: If you use chlorine tablets, place them in a plastic jar with holes in it and dip it into the water. (The tablets can leave burn marks if they are in direct contact with the wood). Just read the instructions that apply to the chemical you are using to sanitize the water and follow those safety instructions.
All in all, we recommend fitting a filtration system or using a sanitizing treatment like chlorine if you want to leave the water in for longer.
TIP: While some hot tubs are appropriate for use with chlorine, not all are. Chlorine or Bromine damages the wood with overuse.
Therefore, it is best to use a non-chlorine shock treatment for domestic use such as a shock oxidizer, used once a week.
To clean dirt at the bottom of the vat, use a vacuum head and a pool sieve to catch free-floating debris. If your hot tub is equipped with a filtration system, most of the work will already be taken care of for you.
After draining the water, clean the hot tub with water and mild soap.
You also need to remove ashes from the stove regularly.
To do so, wait until the stove has cooled and remove the baffle plate and the grating. Use a long-handled scoop to remove the ashes from the stove. Alternatively, some stoves can be unscrewed, lifted out, and turned upside-down.
Regularly check the condition of the chimney. Sometimes, it may need to be replaced depending on the environment in which the outdoor hot tub is placed
5. Drain Your Tub
When overused water sits in your tub for long periods, problems like odor, murkiness, algae buildup, or hot tub foam can crop up.
By draining, cleaning, and refilling your hot tub every few months, you’ll get to enjoy relaxing in sparkling clean water.
Drain the tub through the valve on the bottom of your spa to let the water out. If your tub isn’t connected to a drainpipe, you can drain the water with a hose. A submersible pump can also be used to speed up the process.
6. Treat Your Tub 1-2 Times a Year
If the wood is exposed to sunlight for extended periods, the color will fade, which is why it should be promptly treated with UV protection varnish.
If the color has already started to fade, you may use a brown-pigmented varnish to renew the color of the wood.
Treat the hot tub 1-2 times a year from its outside for longevity and aesthetics.
It can also be painted with a linseed oil mixture, with or without pigment, consisting of one part linseed oil and two parts turpentine. Therefore you should, if possible, rotate the hot tub half a turn after a couple of years.
Is A Wood-fired Tub Worth It?
Inspired by the Japanese soaking tubs, wood-fired hot tubs look beautiful and stylish and thanks to their innovative design, they are built to last.
Where users enjoy the pleasures of a wood-fired hot tub soak during weekends and holidays to supplement an outdoor shower, then a wood-fired hot tub is worth it.
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