Wood-Fired or Heat-Pump Hot Tub: Which Heating Option Is Right for You?

The right heating system depends on how you want to use your hot tub. A wood-fired stove gives you the atmosphere of a real fire, while a heat pump can keep the water at your chosen temperature, ready when you are.

For many owners, the choice comes down to convenience, running costs and whether burning wood is practical at home.

Wood-fired hot tubs: the traditional experience

A wood-fired stove heats the water directly. Lighting and tending the fire is part of the experience, but it takes planning: allow around two to two and a half hours to heat the tub, depending on its size, starting water temperature and weather. Birchwells gives a guide of around 90 minutes for its two-person tub and about two hours for its larger tubs. (Birchwells hot tub information)

Advantages

• Enjoy the atmosphere and ritual of a real wood fire
• Heat the water directly with a stove, without relying on a direct electric heater
• Choose how and when to tend the fire as the water heats
• No high electric bills

Things to consider

• You need to source, store and handle firewood, and allow time to light and tend the stove
• You need to consider smoke, the flue and whether a wood-burning appliance suits your property
• Heating takes advance planning
• Stirring the water two or three times with a wooden paddle can help it heat more quickly. Birchwells offers a stirring paddle for this purpose (Birchwells hot tub information)

Heat-pump hot tubs: warm water when you want it

A heat pump transfers heat from the outside air into the water. If you keep the tub filled and the heat pump running, it can maintain the set temperature so the water is ready when you want to use it. It does not mean a freshly filled tub will heat instantly: the pump still needs time to bring cold water up to temperature.

Birchwells’ heat-pump model is generously insulated and includes an insulated cover, which helps limit heat loss. The pump can then top up the heat as needed, instead of starting from cold each time. (Birchwells)

Advantages

• Keep the water at bathing temperature, ready for a spontaneous soak
• Avoid storing firewood, lighting a fire or dealing with smoke
• Use less electricity than a direct electric heater to deliver the same amount of heat, according to the Poolex product data

Things to consider

• The tub needs to remain filled and powered to maintain its temperature
• A heat pump takes time to bring cold water up to temperature
• Performance and running costs depend on air temperature, water temperature, insulation, use and your electricity tariff

How much electricity can a heat pump save?

A direct electric resistance heater turns electricity into heat at roughly a one-to-one ratio: one unit of electricity produces one unit of heat. A heat pump moves heat from the air, so it can deliver more heat for each unit of electricity it uses. The Energy Saving Trust explains this using the coefficient of performance (COP): a COP of 3 means three units of heat for every unit of electricity. (Energy Saving Trust guide)

The Poolex Spawer Ice Spa data sheet gives a more specific comparison for Birchwells’ 7 kW heat-pump option. At -10°C air temperature and 38°C water temperature, it lists a COP range of 1.8–2.1. That works out to roughly 44–52% less electricity than a direct electric heater for the same amount of heat under those test conditions. This is a calculated comparison from the published COP, not a promise of a particular daily or annual bill. (Poolex Spawer Ice Spa product information)

Poolex advertises savings of up to 75% compared with traditional electric heaters, but that is a maximum claim and will depend on operating conditions. The cold-weather test figures above give a more specific comparison for the stated conditions. (Poolex Spawer Ice Spa product information)

Why consider a heat pump in London?

In a London garden, burning wood may be impractical because of nearby homes, property rules, smoke concerns or local restrictions. A heat pump avoids burning wood, so it can be a convenient alternative where a wood-fired stove does not suit the setting.

Smoke-control rules depend on your location and appliance; they do not amount to a blanket ban on every outdoor fire. Check with your local council and, if relevant, your landlord or property manager before choosing a wood-fired model. (GOV.UK smoke-control rules; Mayor of London guidance on wood burning)

Which heating option is right for you?

Choose wood-fired if you enjoy tending a fire, value its atmosphere and have the space and time to store firewood and heat the water in advance.

Choose a heat pump if you want the tub kept at temperature and ready to use, prefer not to burn wood, or want to use less electricity than a direct electric heater for the same heat output.

Birchwells’ Poolex heat pump combines ongoing temperature maintenance with an insulated tub and cover. For customers who want warm water without planning around a fire, it is a practical option to consider.