Swimming Pool Heat Pumps: A Comprehensive Guide

A swimming pool is a fantastic addition to any home, providing endless opportunities for enjoyment and relaxation and giving a luxurious boost to your outdoor space.

Unfortunately, the UK’s unpredictable weather can put a dampener on your hopes of enjoying your pool even in the warmer months. And that’s why a swimming pool heat pump is essential, helping you to keep your pool at a comfortable temperature even in cooler weather.

A swimming pool heat pump helps you to make the most of your pool – but only if you choose the right pump for your needs. In this post, we break down how swimming pool heat pumps work, the benefits they offer, and how you can make sure you buy the right pump for your pool.

What is a swimming pool heat pump?

A swimming pool heat pump extracts heat from the surrounding air and transfers it to your pool water. This process allows you to maintain a comfortable water temperature, even when the outside air is cool.

By utilising the natural heat energy in the air, heat pumps provide an energy-efficient and environmentally friendly way to warm your pool. Whether you want to extend your swimming season into the shoulder months or enjoy a warm dip on a chilly day, a pool heat pump is the perfect choice.

Before we explore the best swimming pool heat pump options for you, let’s look a bit closer at how the process works.

How does a swimming pool heat pump work?

A swimming pool heat pump works using a process similar to a refrigerator, just in reverse. Instead of directly creating heat itself, the pump absorbs heat from the air and transfers it to the water in your pool, making it an efficient and eco-friendly option.

The cycle starts when a fan draws outside air across an evaporator coil, which acts as a heat collector. This coil contains a refrigerant, a liquid designed to absorb heat easily. As it absorbs heat from the air, the refrigerant transforms from a liquid into a warm gas. This gas is then directed into a compressor, which compresses it to increase its temperature further, intensifying the heat.

Once compressed, this now very hot gas flows into a heat exchanger (also called a condenser), where the actual heat transfer to the pool water takes place. As the pool water passes through the heat exchanger, the heated refrigerant gas releases its energy to the water, warming it. In the process, the refrigerant gas cools down, returning to a liquid state.

After releasing its heat to the pool water, the liquid refrigerant flows back through an expansion valve, reducing its pressure and cooling it before re-entering the evaporator coil. This cooling resets the refrigerant, allowing it to absorb heat from the air again, and the cycle continues.

This constant cycle of absorbing, intensifying, and transferring heat enables the heat pump to maintain a comfortable pool temperature efficiently, without burning fuel or using high-energy heating elements. Instead, it makes use of the surrounding air’s ambient heat, making it a sustainable option for pool heating.

Choosing the right swimming pool heat pump

We’ve hopefully made clear that a swimming pool heat pump is a great choice if you want to get as much enjoyment as possible from your swimming pool. But it’s important to choose the right pump for your needs – and that’s not as simple as it might seem.

Selecting the ideal heat pump for your pool involves considering a few key factors to ensure you get the best performance and efficiency for your needs. Here’s a look at some of the key factors to keep in mind:

• Pool size and heat pump capacity. The size of your pool is a major determinant in choosing the correct heat pump capacity. Larger pools need more powerful heat pumps, typically measured in British Thermal Units (BTUs) or kilowatts. A heat pump with higher BTUs or kilowatts will heat the water more quickly and maintain a stable temperature, especially in larger pools. Read on below for a more detailed overview of how to choose the right size heat pump for your pool.

• Desired water temperature. The temperature you want to maintain in your pool affects how powerful a heat pump you’ll need. If you prefer very warm water, especially in cooler seasons, choose a unit with higher capacity or one designed to operate in colder conditions. For year-round use, a more robust model with reliable heating performance at lower temperatures is ideal.

• Operating costs. Heat pumps can be a cost-effective choice over time, but operating costs vary based on energy efficiency ratings. Look for a model with a high coefficient of performance (COP), which measures how efficiently the pump converts energy into heat. A higher COP rating indicates lower energy consumption and, therefore, lower operating costs.
• Pool usage patterns. Consider how frequently you plan to use your pool and during which months. If you use your pool sporadically or only in summer, a standard heat pump will be sufficient. However, if you need consistent, rapid heating, especially outside peak summer months, you may want to invest in a more powerful or specially designed model for extended seasons.

As you can see, there are a range of important issues to consider when deciding on the right heat pump for you. But the most essential of these is the size and capacity of the pump itself. Ultimately, if your heat pump is simply not powerful enough to heat your pool, you won’t see any of the intended benefits.

With this in mind, let’s look more closely at how to choose the right size of heat pump for your pool.

Swimming pool heat pump size guide

Sizing a heat pump for your pool requires careful consideration of several factors that influence heat loss. While there’s no one-size-fits-all solution, understanding the variables that impact heat retention can help you make an informed choice.

One of the primary factors in choosing the right heat pump size is the amount of heat your pool loses each hour. Heat pump manufacturers base their sizing calculations on this estimated heat loss, measured in kilowatts (kW).

Key elements affecting heat loss include the thermal properties of your pool structure, local wind speed, water velocity, and even the depth of the water table. Additionally, using a heat retention pool cover significantly reduces heat loss, helping maintain your desired temperature more efficiently and allowing for a potentially smaller pump.

To find the right size, match the kW output of the pump to the estimated hourly heat loss of your pool. Selecting a pump that can exceed this heat loss is often advisable, as it will help you achieve and sustain the ideal temperature, even in less-than-ideal conditions. Refer to our Swimming Pool Heat Pump Size Guide Chart below for more specific recommendations based on pool size and estimated heat loss.

Swimming pool heat pumps we stock

Mr Perfect Heat Pump

The Mr Perfect Heat Pump sets a new standard for silent operation and performance in pool heating, featuring the patented InverPad® Turbo technology by Aquark Technology. This innovative heat pump utilises the Turbofan system, which combines advanced noise-cancelling features with aerodynamic optimization to achieve ultra-quiet operation, ensuring minimal mechanical noise even at high performance levels.

Designed to handle the toughest weather conditions, Mr Perfect’s unique TurboFan airflow system increases the heat exchange area, maximising output to keep pools warm year-round. The pump also features EEV (Electronic Expansion Valve) technology, boosting the COP by up to 20%, and a twisted titanium heat exchanger that increases efficiency by 40%.

 

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Waterco Ultra Inverter Heat Pump Top Mount (31/39kW)

This powerful top-mount model from Waterco is designed for larger pools, with a 31 or 39kW output that allows it to efficiently heat substantial volumes of water.

Its ultra-inverter technology provides adjustable heating capacity, which means it can vary output to conserve energy when lower power is sufficient.

This model is ideal for those seeking fast heating times without compromising efficiency.

 

 

 

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Waterco Ultra Inverter Heat Pump Top Mount (17/21kW)

The Waterco Ultra Inverter Heat Pump Top Mount (17/21kW) offers similar advanced inverter features to its larger counterpart but at a lower power output, making it suitable for smaller to mid-sized pools.

With a heating capacity of 17 or 21kW, it balances efficiency and power, providing steady, energy-conscious heating that’s ideal if your pool gets a great deal of sunlight and does not get much wind exposure.

 

 

 

 

 

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Waterco Aquaflow XL Inverter Heat Pump – Side Mount

The Waterco Aquaflow XL is a high-performance side-mount heat pump, which uses Waterco’s advanced inverter technology for precise temperature control and optimised energy usage. It’s side-mount fan design makes it a good choice for installations where vertical clearance might be limited, such as spaces adjacent to walls or fences.

The Aquaflow XL offers the flexibility of variable-speed heating, allowing it to conserve energy during low demand and ramp up power as needed.

It’s ideal for users who want a balance between efficiency and performance, particularly in pools that benefit from consistent temperature control throughout the day.

 

 

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Getting the most out of your heat pump

The amount of heat your swimming pool heat pump consumes will depend on the ambient air temperature and the corresponding temperature of your pool water. To get the most out of your heat pump, it’s essential that you operate your pool heater at realistic temperatures to obtain the desired outcome without excessive energy consumption.

This is particularly important early and late in the season, when ambient temperatures are likely to be lower. Read on below for our advice on how to tailor your pool heat pump usage for optimal performance all year round.

Early season

We recommend that heat pumps are only operated when the ambient air temperatures are in excess of 15°C. If you decide to operate the heater below this temperature or at night your running costs may rise exponentially.

It is our advice to run the heat pump 12 hours per day. If a plumbing bypass (recommended) has been installed, we suggest that until the water temperature has reached 21°C that only  60% of the water flow is passed through the heater – please see below diagram.

Late season

Toward the end of the summer and into autumn, you’ll benefit from using functions that are specifically designed to keep your heat pumps operating in cooler temperatures.

Heat pumps with an ‘ambient defrost function’ generally operate effectively until mid-September. When air temperatures fall below 10°C, ice may begin to form on the exterior of the unit. In such cases, the heater defrosts itself by using ambient air to melt the ice. Once the ice has melted, the heater automatically switches back to heating mode, repeating the defrosting process as needed. It’s worth noting that running the heater in consistently low temperatures can become uneconomical, so caution is advised.

In contrast, heat pumps with a ‘hot gas defrost function’ can extend pool heating further into the cooler season. Ice that forms on these units is cleared more rapidly by reversing the flow of hot refrigerant, allowing the heater to resume heating mode quickly. However, if the ambient temperature is low enough to keep the unit in ‘defrost mode’ continuously, heating may become inefficient or fail to reach the desired pool temperature.

Find the right swimming pool heat pump with Paramount Pools

A swimming pool heat pump is essential for extending your swim season and ensuring you enjoy the perfect water temperature, no matter the weather. But with so many models available, each designed for different pool sizes and energy efficiency needs, finding the right one can feel overwhelming. And that’s where Paramount Pools can make all the difference.

Whether you need guidance on energy efficiency, noise levels, or seasonal performance, we’ll help you weigh your options and find the model that best fits your budget and preferences. Don’t leave your pool comfort to chance – get in touch for expert advice and support in selecting the perfect heat pump for your swimming pool.

We also sell alternative forms of swimming pool heating.