Choosing The Right Heat Pump / Chiller For Your Pool - A Selection Guide

Heat Pumps, Chillers and Combined Heat Pump / Chillers are the modern, efficient solutions to controlling your pool temperature. No longer are you stuck with an uncomfortably warm pool in the peak of summer heat or with prohibitively cool/cold water that can only be warmed at great expense. Unlike traditional pool heaters that consume both energy and your budget at alarming rates, heat pumps and chillers operate much like air conditioners, transferring heat from the air to the pool (warming it) or from the pool to the air (cooling the pool).

Today’s heat pumps and chillers provide you with affordable control of the length your swimming season and control over how comfortable & refreshing the water is. Follow along as we guide you through selecting the best unit for you and your pool.

Equipment Types

Purpose:

Heat-Only

This remains the highest selling category due in no small part to their lower cost and, to some degree, insufficient awareness of the value of dual-purpose systems.

Chill-Only

These units represent the smallest segment of the market due in part to their more limited geographic application.

Heat/Chill Combination

Combination units represent the fastest growing segment of the market and already dominate in markets across the southern states where peak summer temperatures can reduce the refreshment offered as the pool starts to feel like a warm bathtub. The ability to both heat and cool is achieved through valving that allows a reversal of refrigerant flow permitting the unit to then transfer heat from the water which is expelled to the air.

Surprisingly, many heat/chill models are actually ideal for northern climates as well, as the reversal technology can allow the heat mode to continue to work down into even colder air temperatures where a heat-only model might stop working.

Climate Suitability

Some units are specifically optimized for cooler climates and will be labeled as Low Ambient Temperature or Cold Climate models. Overwhelmingly, these units employ Inverter Technology - essentially a variable speed compressor - as well as reversal valving in order to create a defrost cycle for coolant lines.

Once you’ve designed a system with the ability to reverse flow and defrost lines, the basic ability to operate as a chiller is also in place. Consequently, the preponderance of units able to heat efficiently below about 50 degrees are Combination Heat/Chill Inverter units. So if you are in a northern climate, don’t just write off dual mode models!

Sizing Your System

Pool Size:

As a first step, determine the dimensions of your pool in order to calculate the surface area and the volume in gallons if you don’t already know it. If you have dimensions, but don’t know the volume, you can calculate it here. These numbers will be needed as we move ahead in sizing the Heat Pump.

Heating Capacity:

The heating capacity is measured in British Thermal Units (BTU) and the goal here is to filter out systems that fail to meet your pool’s requirements.

Use each manufacturer's "calculator" in order to determine which of their models meet or exceed your requirements. These calculators typically are based on the pool’s surface area, total gallons, targeted pool temperature, your location and your target temperature. They include regional or even city-level estimates of how your climate will impact your choice and how much of the year you might be able to use a given model. In addition it may also provide estimates of the cost month-by-month to maintain your target temperature.

If your budget permits, it is advisable to choose one (1) model larger than the unit that minimally meets your needs. Oversizing is beneficial in moderation, but too much larger will simply cost more (and give up efficiency as well unless it is a variable-speed inverter model). In some instances, your target temperature may not be attainable while in others you may simply decide that certain months aren’t worth spending your budget on even if it is possible to still heat the pool at that time.

Manufacturers’ Sizing Calculator Examples

• AquaCal
• PAL
• RayPak

Heating Efficiency:

Compare the Coefficient of Performance (COP) on the qualifying units. The COP is a standardized measure of efficiency and a higher COP means better efficiency. Generally, heat pumps with Variable-Speed Compressors (“Inverter Heat Pumps") - offer the highest efficiency.

Installation Requirements

Measure the space you have available to install a Heat Pump and compare it to the dimensions of the models under consideration.

Some Heat Pumps are top-discharge, some are side-discharge. Consider this in terms of whether a particular model will or won’t lend itself to working with your specific space, layout, and equipment.

Review the product manual for any stated requirements for airflow space. Will you have enough room for required airflow and to access the unit for maintenance?

This is also the time to check the unit’s electrical requirements. Determine whether you have an available and adequately sized circuit and breaker for the heat pump to operate safely and correctly, or if you’ll be able to add a large-enough one into your breaker panel.

Noise Levels

Check the decibel rating of each model. Decibels are non-linear in scale meaning in this context that every decibel increase sounds louder than the one before. While most heat pumps are fairly quiet, this could impact your choice if it’s going to be installed adjacent to a living area, for example.

Durability and Build Quality

Confirm that a specific model is made with corrosion-resistant materials. Variable-Speed Compressors and Inverter Heat Pumps are indicative of higher end models with greater efficiency.

Longer, better warranties can be indicators of the manufacturer’s faith in their product as well as a little reassurance in case you have problems. Look over the warranty and confirm what will be covered. Some warranties break down their coverage and warranty length by region.

Features

Make note of any special features that make a specific model better suited to how you envision working with the system. These may include onboard programmable controls, versus having Wi-Fi Connectivity for remote control of the unit. Dual-mode heat/chill units may have automatic temperature mode switching, or might have to be manually set on heat or cool mode. If you also have a traditional heater then choosing a model with a Hybrid mode is important, which coordinates operation with your gas heater.

This gives you a good starting point for equipping your pool with the right heat pump for your pool, your lifestyle, and your budget. If you would like to learn more, check the other articles listed below.

FAQs