When buying a hot tub, the cost price is usually the first thing people think about. But the running costs can make just as much of a difference in the long run. Once you've picked the size and model, it's worth considering how much it'll cost to keep it running—so you don't get hit with unexpected bills.

In this guide, we'll break down the differences between 13 amp and 32 amp hot tubs, what affects their running costs, and how you can keep expenses low while still enjoying a relaxing soak.

But before we dive into the comparisons, let's go over the basics.

What is a 13 amp Hot Tub?

A 13 amp hot tub is a plug-and-play model that runs on a standard household socket. You don't need an electrician to install it—plug it in and enjoy. It's a good choice if you are looking for a simple, budget-friendly hot tub for occasional use. Since it runs on low power, it may take longer to heat up and might not keep water for long in colder weather. By the way, we have more hot tubs variety in our main collection if you are interested.

What is a 32 amp Hot Tub?

A 32 amp hot tub is a more robust model that requires a dedicated electrical connection. It requires a qualified electrician to install, but in return, it offers faster heating, stronger jets, and better performance. The hot tub keeps water warm even in cold weather, so that it can be used year-round. This makes a 32 amp hot tub a great choice if you want a more luxurious and high-performance hot tub experience.

What are the Key Differences Between 13 Amp and 32 Amp Hot Tubs?

A 13 amp hot tub plugs straight into a standard household socket, so you can get it up and running quickly without needing an electrician. A 32 amp hot tub, however, requires a dedicated power supply and an isolator (for safety), which an electrician must install. This extra power means a 32 amp model can run more features simultaneously without losing performance.

Other differences are: 

Heating Speed: 

Heating speed is another key difference. A 13 amp tub typically has a 2kW heater (sometimes more), while a 32 amp model usually comes with a 3kW heater or higher. 

For instance, if you fill both a 13 amp and a 32 amp hot tub with cold water, the 13 amp tub, with its 2kW heater, might take around 6 hours to reach 38°C, while the 32 amp tub, with its 3kW heater, could do it in about 3-4 hours. The extra power helps heat the water faster and maintain the temperature longer—especially in winter. 

Pump and Jet Power

Pump and jet power also play a big role. A 13 amp hot tub usually has one pump powering all the jets, so the pressure is lower, mainly if there are many jets. In most cases, it also can't simultaneously run the heater and jets at full power. A 32 amp tub, on the other hand, has two or more pumps, giving the jets much stronger pressure while keeping the heater running at full strength.

Overall, a 13 amp hot tub is great for casual use, especially in warmer months. A 32 amp model is better if you use your hot tub often, want stronger jets, or need faster heating, especially in colder weather.

Running Costs: 13 Amp vs. 32 Amp Hot Tub

The cost of running a hot tub depends on three main factors: how much energy it uses, how much you spend on maintenance and other consumables, and how often you use it. To help you understand what to expect, let's break down the costs of electricity, maintenance, and consumables.

Daily and Monthly Electricity Cost

Heating and maintaining water temperature accounts for a large portion of a hot tub's running costs. The more powerful the heater, the faster it heats up—but it also uses more electricity per hour. 

While both 13 and 32 amp can heat the water to 40°C(standard temperature for a hot tub), the 13 amp tub takes longer to reach this temperature due to its lower-powered heater. 

• A 13 amp hot tub with a 2kW heater uses 2 kWh of electricity per hour when heating.

• A 32 amp hot tub with a 3kW heater uses 3 kWh per hour when heating.

Electricity cost depends on your provider and location, but the UK average is £0.30 per kWh. If your hot tub runs for 4-6 hours a day to maintain heat, it means 

• 13 amp tub uses 8-12 kWh per day, that is £2.40-£3.60 daily and £72-£108 per month. 

• 32 amp tub uses 6-10 kWh per day, that is £1.80-£3.00 daily and £54-£90 per month.

With this, a 32 amp hot tub costs less to run daily and monthly because it heats faster and holds heat better. A 13 amp model runs longer to maintain the same temperature, which results in higher costs over time.

It's best to keep your hot tub on at all times. Turning it off completely may seem like a way to save energy, but reheating it from cold often costs more in the long run.

If you don't use your hot tub daily, you can lower the temperature to around 30°C to save energy while keeping it warm enough for a quicker heat-up. Remember to maintain the water properly, as stagnant water can develop bacteria and algae.

Maintenance and Consumables Costs

Beyond electricity, there are also maintenance and consumables costs, which include water treatment, filter replacements, and general upkeep. Regular maintenance keeps the water safe and extends the lifespan of the hot tub's components.

Refills

To extend your hot tub's lifespan, we recommend draining and refilling it every three to four months.  Each refill may cost between £5 to £10, depending on local water rates and volume.

Filters

These help keep your water clean by trapping dirt and debris. With a 32 amp hot tub, you may need larger or multiple filters because it holds more water, has stronger pumps, and has more jets—meaning it circulates and filters more water. As a result, you may spend slightly more on replacement filters and maintenance compared to a 13 amp model, which usually has a smaller filtration system.

Chemicals

Chemicals are essential for balancing water quality and preventing bacteria growth. A 32 amp tub, especially with frequent use, may require more chemicals. Depending on usage and the specific chemicals you use, you can spend around £200 to £350. 

Annual Servicing

Regular servicing ensures your hot tub remains in optimal condition. Some providers offer service plans from around £25 to £30 per month, which may include regular maintenance visits and additional services. A professional service costs approximately £150 to £200 per year. 

Cover Replacement

Over time, covers wear out and need replacing—usually every 3 to 5 years, depending on use and weather conditions. The cost of replacing a hot tub cover varies based on size, quality, and brand. 

On average, prices range from £200 to £500, with premium covers reaching up to £1,200. This is why investing in a high-quality hot tub from the start is best. Otherwise, frequent repairs and replacements will cost you more in the long run. 

Overall, the total estimated cost per year for a 13 amp hot tub ranges from £1,334-£2,086, while a 32 amp hot tub costs between £1,238-£2,140, considering electricity, maintenance, and consumables. Also read our piece on how you can shock a hot tub.

Factors That Impact Hot Tub Running Costs

Several factors affect your energy bills when running a hot tub. Understanding these can help you manage costs while enjoying your spa.

1. The Hot Tub Heater

Your hot tub's heater plays a significant role in energy consumption. A more powerful heater 3kW, (like those in 32 amp models) warms the water faster, so it runs for less time and wastes less energy. A less powerful heater, 2kW (found in 13 amp models), takes longer to heat up, using more electricity in the long run. 

If your tub struggles to stay warm, the heater works harder, which raises costs. Some heaters are more energy-efficient than others. For example, titanium heaters transfer heat better than stainless steel ones, so it's worth checking the specifications before choosing a hot tub.

2. Insulation Quality

Good insulation helps your hot tub stay warm for longer, so the heater doesn't have to work as hard. If a hot tub isn't well-insulated, heat escapes quickly, and the heater has to keep running to maintain the temperature, which results in higher electricity bills.

Think of it like a thermal flask—when it's well-insulated, your drink stays hot for hours. But if the insulation is poor, the heat escapes and your drink cools down fast. The same happens with a hot tub.

Some hot tubs have thick foam insulation around the shell and base, efficiently trapping heat inside. Others may have thin or low-quality insulation, causing heat to escape, especially in cold weather. In that case, the heater will need to run more often to keep the water warm, consuming more electricity and increasing overall running costs, especially during winter.

3. The Volume of Spa Water

The amount of water in your hot tub directly affects running costs. A standard 13 amp model can hold up to 800 litres, while a 32 amp tub can hold up to 1,500 litres, depending on size. A larger tub takes longer to heat, especially if it has only one pump, as seen in bigger 13 amp models. For example, an 800-litre 13 amp tub will take far longer to heat than a 400-litre version.

More water also means higher maintenance costs. You'll need more chemicals to keep the hot tub clean and more energy for filtration. The pump will run longer to circulate and filter the water, increasing electricity use. To avoid unnecessary costs, choose a hot tub that fits your usual number of bathers rather than going too big.

4. Frequency of Use

The more often you use your hot tub, the more energy it consumes. Frequent use means more reheating and filtration cycles, increasing electricity bills. If you use your hot tub daily, consider going for hot tubs with energy-saving modes to reduce running costs.

5. Cover Efficiency

Your hot tub cover plays a vital role in heat retention. A high-quality, well-fitted cover prevents heat from escaping and reduces the need for constant reheating. If your cover is old, damaged, or poorly insulated, you could lose a lot of heat and waste energy. Investing in a good cover helps cut costs in the long run.

6. Outdoor Temperature and Wind Exposure

Cold weather and strong winds cause your hot tub to lose heat faster, making the heater work harder and increasing energy costs. If your hot tub is in an open or exposed area, it will take longer to heat and struggle to maintain the temperature, especially in winter. Placing it in a sheltered spot near a fence, wall, or garage helps reduce heat loss and keeps running costs lower.

7. Energy-Saving Features

Many modern hot tubs have energy-efficient settings, such as timers, economy modes, and improved pump systems. These features help reduce electricity use without affecting performance. Choosing an energy-efficient model can significantly affect monthly running costs.

Which One Is More Affordable in the Long Run?

Your choice depends on how often you plan to use the hot tub and the climate you live in. A 13 amp hot tub is cheaper to buy and run short-term, making it suitable for light or occasional use. However, it works harder in colder months, increasing electricity costs over time.

On the other hand, a 32 amp hot tub has higher initial and lower running costs (in the long run). Still, its faster heating, better heat retention, and ability to run all features simultaneously make it more efficient for frequent use, especially in winter.

How to Keep Your Hot Tub's Running Costs Low

• Buy a quality hot tub with full insulation and an energy-efficient heater to reduce heating costs.

• Place your hot tub in a sheltered area to prevent heat loss from wind exposure.

• Always seal the cover properly after each use to stop heat from escaping.

• Close the air jets when the tub is not in use to prevent cold air from cooling the water.

• Lower the temperature by a few degrees to save electricity, especially when you don't use the tub for a while.

• Clean the filter regularly to keep the system running efficiently and reduce energy consumption.

• Compare energy tariffs yearly and switch to a cheaper provider to reduce electricity costs.

• Maintain proper pH levels to prevent damage to the heater and avoid expensive repairs.

• To save energy in the long run, leave the hot tub running at a steady temperature instead of reheating it to a cold temperature.

The Bottom Line

When comparing the running costs of 13 amp and 32 amp hot tubs, the best choice depends on your usage and budget. A 13 amp hot tub uses less power per hour but takes longer to heat, potentially increasing electricity costs. A 32 amp model heats faster, retains heat better, and runs more efficiently in the long run. 

While maintenance costs are similar, a 32 amp tub may require more filters and chemicals. A 13 amp tub is great for lower upfront costs and occasional use. However, a 32 amp hot tub is worth the investment for frequent use and better efficiency.

Ready to find the perfect hot tub? Check out our collection of premium 13 amp and 32 amp models. We offer a range of efficient and fully insulated hot tubs that help you keep running costs low while delivering the best relaxation experience.  

FAQs

Which is best, a 13 Amp or 32 Amp hot tub? 

The choice between a 13 amp and a 32 amp hot tub depends on your preferences and requirements. If you prioritise easy installation and low-cost price, go for a 13 amp model. If you prefer higher performance and are willing to invest in extra bucks in the installation, then a 32 amp hot tub is the way to go. 

How much does it cost to run a 32 Amp hot tub? 

On average, it costs £0.30 per kWh to run a 32 amp hot tub. However, this depends on various factors, including the brand, energy efficiency, usage patterns, and current electricity tariffs.  

How many amps does a hot tub need? 

Hot tubs require either a 13 amp or a 32 amp electrical supply. A 13 amp hot tub can be plugged into a standard household socket, while a 32 amp hot tub needs a dedicated electrical connection installed by a certified electrician. The required amperage depends on the hot tub's specifications and features. 

How long does it take to heat a 13 Amp hot tub?

The time required to heat a 13 amp hot tub depends on factors such as the initial water temperature, the desired temperature, ambient conditions, and the hot tub's heater capacity. 

Generally, a 13 amp hot tub with a 2 kW heater will take longer to heat the water compared to a 32 amp model with a more powerful heater. Specific heating times can vary, and it's advisable to consult the manufacturer's guidelines for precise information.