How Much Electric Do Hot Tubs Use

Hot tubs are one of the most enjoyable home luxuries, offering relaxation, hydrotherapy, and a touch of spa-style comfort in your garden. However, many homeowners are surprised when they first discover how much electricity these installations consume. Understanding how hot tubs use electric power, how much they cost to run, and what can influence their efficiency helps you make an informed decision about ownership. The power used by a hot tub depends on several factors, including its size, heater type, insulation quality, and how often it is used.

Average Power Consumption of a Hot Tub

Most domestic hot tubs in the UK use between 1.5 kW and 7.5 kW of electrical power, depending on their size and heating system. Smaller two or three-person tubs with efficient insulation typically operate on a 13 amp plug and use around 2 to 3 kW of power. Larger models with multiple pumps and built-in heaters require a dedicated 32 amp supply and can draw between 6 and 7.5 kW. The energy consumption depends heavily on how often the water is heated from cold and how well the hot tub retains its temperature when not in use.

Typical Running Costs in the UK

At the current UK electricity rate of around 30 pence per kWh, the cost of running a hot tub can vary between £1.50 and £3.00 per day for smaller models and £3.00 to £6.00 per day for larger, more powerful ones. This estimate assumes average outdoor temperatures and moderate use. During colder months, energy use naturally increases as the water heater works harder to maintain the temperature, especially if the hot tub is kept outside without adequate shelter or insulation. Over a full month, that means the average household could spend between £45 and £180 on electricity for a hot tub, depending on how often it is used.

The Role of Heaters and Pumps

The heater is the most energy-intensive part of a hot tub, responsible for maintaining the water at the desired temperature, typically around 37 to 40 degrees Celsius. When first filling and heating the tub from cold, the heater can run continuously for several hours, drawing significant power. Once the target temperature is reached, the heater cycles on and off to maintain warmth. Circulation and jet pumps also use electricity, although less than the heater. The more pumps and jets a hot tub has, the more energy it will consume. Models designed with energy-efficient pumps and variable speed settings can help reduce this demand without compromising performance.

How Usage Habits Affect Electricity Consumption

Your personal habits have a major influence on how much electricity your hot tub uses. Leaving the cover off for extended periods allows heat to escape, forcing the heater to work harder. Running the jets continuously adds to consumption, as pumps draw power each time they are used. Heating the water from cold more frequently rather than maintaining a steady temperature is another common cause of high bills. Many owners find that leaving the tub set to a consistent temperature, rather than reheating it each time, actually reduces overall energy use. The key is maintaining good insulation and using a well-fitted thermal cover when the hot tub is not in use.

Hot Tub Installation and Electrical Supply

Hot tubs are available as either plug-and-play 13 amp units or hard-wired 32 amp installations. Plug-and-play tubs can be connected to a standard outdoor socket, though it must be on a dedicated circuit protected by an RCD for safety. These models heat the water more slowly and may not support simultaneous use of jets and heaters. Hard-wired hot tubs, which require a professional electrician, offer faster heating and stronger pump performance but draw much higher current. A qualified electrician will ensure the installation meets BS7671 Wiring Regulations, includes proper earthing, and is compliant with Part P of the Building Regulations.

Environmental and Efficiency Factors

Insulation is one of the most important aspects of hot tub efficiency. A well-insulated shell and base help retain heat for longer, meaning the heater cycles less often. Cheaper models with poor insulation can lose heat rapidly, consuming far more power. Using an insulated lid or thermal cover prevents heat escaping through the surface, especially overnight. Placing the hot tub in a sheltered area away from strong winds and covering it when not in use also helps reduce energy loss. Some owners choose to use floating spa blankets that sit directly on the water surface, adding an extra layer of insulation.

Seasonal Variations in Energy Use

The time of year has a significant impact on energy consumption. During the summer, ambient air temperatures are higher, so the heater works less to maintain water warmth. In winter, the heater must operate more frequently, particularly if the hot tub is outdoors and exposed to cold air. Many owners choose to reduce the temperature setting slightly during colder months to save energy without losing comfort. Others opt to use the hot tub less frequently in winter or switch it off entirely when not needed for extended periods. Regular maintenance, including keeping the filters clean and the water balanced, also ensures the system runs efficiently year-round.

Energy-Saving Tips for Hot Tub Owners

There are several practical ways to keep your hot tub’s energy use under control. Using a high-quality insulated cover, checking the seals around the lid, and ensuring the cabinet panels are properly fitted can all make a difference. Setting the temperature to around 37 degrees rather than the maximum 40 degrees reduces heater workload and lowers running costs. Running filtration cycles during off-peak electricity hours, if your tariff allows, can also save money. Upgrading to a hot tub with an energy-efficient pump or modern inverter technology further reduces consumption. Choosing an experienced electrician to install the hot tub ensures that it operates safely and efficiently from the start.

How to Estimate the Total Cost of Ownership

Beyond electricity, running a hot tub involves other small costs, including water treatment chemicals and occasional servicing. However, electricity remains the main ongoing expense. A well-maintained hot tub using about 6 kWh per day will cost around £55 per month at current UK rates, while larger or heavily used models could reach £120 per month. If your tub runs on a smart timer or heat retention mode, the cost can be lower. Keeping accurate records of your electricity readings before and after installation helps you understand exactly how much energy your hot tub consumes.

The Importance of Professional Installation

Because hot tubs operate with both electricity and water, proper installation is critical for safety. All outdoor sockets or connections must be weatherproof and RCD protected, and the supply cable must be sized correctly to handle the load. A qualified electrician will assess your consumer unit and may recommend adding a dedicated circuit to avoid overloading existing wiring. This ensures the system operates safely and efficiently, preventing electrical faults or tripped circuits. Registered electricians familiar with outdoor spa installations can guide you through the best setup to balance performance with energy efficiency.

Conclusion: Balancing Comfort and Cost

Hot tubs do use a noticeable amount of electricity, but with good planning and proper maintenance, running costs can be managed effectively. On average, you can expect a modern hot tub to consume between 2 and 7 kW per hour when heating, costing roughly £45 to £180 per month depending on size, insulation, and usage. The key to reducing costs lies in efficient installation, quality insulation, and sensible energy habits. By working with a qualified electrician, you can ensure your hot tub is safely connected, energy-efficient, and ready to deliver all the relaxation and warmth you need without unnecessary expense.