How Much Does It Cost to Run a Wood Fired Hot Tub

What you do and do not pay for

One of the most desirable parts of a wood fired hot tubs is just how simple and connected to nature they are. They can be used like a campfire, as needed on a per-session basis, or more often like you'd use a wood burning fireplace. Depending on your lifestyle and property, it can be incredibly inexpensive, or even free to operate, and it's consciously designed to work with nature rather than against it. 

The running cost picture for a wood fired hot tub is fundamentally different from an electric spa. With wood fired of course, there's no ongoing energy use like there is with electricity. There's no heating element drawing power, no pump running continuously, and no control system consuming standby energy. The energy bill for a wood fired tub is zero.

What you do pay for, per use: firewood and water. What you pay for annually: water treatments if maintaining the water for extended periods of use. 

The trade-off is that cost-per-use is variable and tied to how you source your wood, whereas an electric tub has a predictable monthly energy cost. For many owners, the wood fired model works out considerably cheaper over time, particularly those with access to wood at low or no cost.

 

Firewood: the main running cost

Firewood is the primary ongoing cost for a wood fired hot tub. How much you spend depends almost entirely on how it's sourced, with many properties having wood available to burn from fallen logs and gathered kindling. 

How much wood does a single soak use?

A typical heat from cold to soaking temperature in a 6ft Standard size AlumiTub uses roughly one to two bundles of hardwood, or the equivalent in loose cord wood. The exact amount depends on:

 

Drier, denser hardwood burns more efficiently and produces more heat per piece. Wet or softwood burns less cleanly and requires more volume to achieve the same result. The quality of your wood directly affects both cost and heat-up time.

Firewood cost by source

Source	Approx cost per session	Notes
Locally sourced or foraged	Minimal to zero	Most common for rural and recreational properties
Purchased in bulk (cord wood)	Low, typically $3 to $8 per session	Cost depends heavily on region and species
Purchased in bags (kiln dried)	Moderate, typically $8 to $15 per session	Convenient, burns cleanly, widely available
Retail bundles (petrol station or shop)	Higher, typically $12 to $20 per session	Least economical, fine for occasional use

 

These figures are approximate and vary by region, season, and wood species. Owners in rural or forested areas, or those who manage their own timber, often have access to wood at negligible cost. For urban users buying kiln-dried bags, costs are higher but still typically lower per session than running an equivalent electric hot tub.

A note on wood species: dense hardwoods such as oak, ash, maple, and birch provide the most efficient burn. Softwoods like pine and spruce ignite easily but burn faster and produce more resin and sparks. See the accompanying guide on the best wood to use for more detail.

 

Water costs per use

A five-hundred-gallon fill at standard municipal water rates costs roughly $2 to $4 in most North American and European jurisdictions. This is a minor cost but worth factoring in if you drain and refill after each period of use, which is the standard approach for a wood fired tub without filtration. A period of use can be anywhere from a weekend or more, depending on whether the tub is being maintained with water treatments or not. 

Some owners fill from a well or collected water source like the ocean, lake or river, reducing this cost further. Others install a filtration add-on, which extends the time between fills and reduces the frequency of full water changes.

If you prefer to maintain water long-term rather than draining after each use, the filtration add-on is available for the wood fired model. It operates on low-voltage plug-and-play power and keeps the water clean between soaks without chemicals being required at every fill.

With any of our Wood Fired systems, the AlumiTub can be safely emptied and left unfilled until its next use, unlike cedar tubs which are subject to damage when left without water.

 

Water care and chemical costs

For a wood fired tub used in the most basic way, draining and refilling after each session, chemical costs are essentially zero. Fresh water, no treatment, drain.

For owners who maintain water longer term, some water treatment is needed. The most low-maintenance approach involves a UV add-on (available on 240V systems with the electric or hybrid filtration kit, not on the basic wood fired filtration add-on) combined with a simple care routine using natural cleaning products.

AlumiTub designed the Good Clean Living preventative water treatment system formulated for low-chemical ownership. Regular use involves keeping the water clean naturally with a hose filter, balancing the water to keep it within safe soaking ranges, and adding a monthly plant-derived stabilizer for tubs that are left filled year-round. For electric models or wood fired hot tubs with filtration, a filter cleanser and filter booster are used to keep the water clean, and sanitation needs are reduced by 60% or significantly more if equipped with UV too. A tub cleanser is also included to safely clean the tub during each water change.  

For wood fired owners using this approach, annual product costs are modest, typically $100 or less, depending on usage frequency. The 6 month kit is sold at $250 including shipping, but this is designed for full time, year-round use in Electric systems and for Wood Fired tubs that aren't used full time, the kit can be extended to last a year or two. Compared to the ongoing treatment expense of a conventional spa requiring consistent chlorine or bromine management, this represents a meaningful saving over time.

 

Maintenance and servicing costs

AlumiTubs are designed to require very little maintenance beyond normal care. The materials are chosen specifically to age well without significant intervention.

Item	Frequency	Approximate cost
Cedar treatment or oil (optional)	Every 1 to 2 years	$20 to $60
Firebox inspection and cleaning	Annually	Owner task, no cost
Chimney cap check	Annually	Owner task, no cost
Filter replacement (if filtration added)	Every 6 to 12 months	$30 to $80 depending on filter type
Lid replacement	Every 5 to 10 years	Varies by model and material

 

The twenty-five year structural warranty covers the tub body itself, which means the primary cost concern over the life of the tub is consumable items rather than structural repairs. The aluminium interior does not corrode or degrade, and the cedar exterior ages gracefully without requiring intensive maintenance.

 

Comparing wood fired vs electric running costs

Electric hot tubs draw ongoing power. A typical residential electric spa running on a 240V circuit uses between 3kW and 6kW of energy per hour during heating and 1kW to 2kW in standby mode. For a tub maintained at temperature around the clock, monthly electricity costs typically range from $50 to $150 depending on energy rates and climate.

Over a year, that is $600 to $1,800 in electricity alone, before water and chemical costs. This is in contrast with wifi-enabled systems like the AlumiTub Electric which are not only consciously designed to reduce energy use with a simplified system, better heat performance, retention and lid use, but it also encourages the use of scheduled heat & filtration settings to eliminate wasted resources during periods when the tub won't be in use. 

A wood fired tub, heated two to three times per week using purchased firewood, might cost $100 to $500 per year in wood depending on source and local pricing. The key difference is that this is optional: you only spend when you soak. There is no standby cost, no overnight heating, no energy consumed when the tub is not in use.

For occasional or weekend use, the wood fired cost advantage is most pronounced. For very frequent daily use, the comparison narrows, but wood fired still avoids the grid cost and installation infrastructure of a permanent electric setup.

 

How to reduce running costs over time