As we approach an unseasonable cool July 4th weekend, what better time to discuss pool heaters. For many years, when someone spoke of a pool heater, they were referring to a gas fired heater. Today, there are many different ways to heat your pool water. Common types can vary by region, and here in the upper Midwest, gas heaters are the most common. Us Midwesterners like the gas heaters because they offer lower upfront costs and the ability to provide both maintenance heating (heater maintains a set temperature in the pool) and recovery heating (heater is expected to bring water temperature back to swim temperature after dropping to ambient temperature).
If you’re interested in extending your swim season with a pool heater, there are many different options. Here are the most common ways to heat your pool water:
Pros: As mentioned above, they can serve both maintenance and recovery situations, cost of initial installation will be lower, will work at all times of the year, no matter what the temperature, and gas costs are typically lower than electric rates.
Cons: Most models are between 81-85% efficient, they require ventilation – both combustion and make-up air to operate properly, and they have set isolation distances from windows and ventilation vents on homes.
Electric Immersion Heater
Pros: Have the lowest cost of initial installation, 100% efficient, have a small footprint so they work well in tight settings, operate the same regardless of ambient weather conditions, and there is no ventilation needed.
Cons: Size can be limited by available power and it can be costly to operate.
Pros: These are very efficient to operate – generally at least 30-40% savings compared to a gas heater and there are no ventilation issues – only that the pump must be placed outside.
Cons: These are physically larger than gas heaters, are designed for maintenance type heating only, and most only produce heat when ambient air temperature is 50 degrees Fahrenheit. In the Midwest, these can normally only be used effectively from June 1st thru September 15th.
Heat Exchangers – these typically receive heat from a boiler or geothermal or solar system
Pros: Compact size and can be very inexpensive to heat with depending on what type of system is providing the heat.
Cons: These can usually only provide maintenance heating and the systems supplying heat to the exchanger can be expensive depending on what type of system provides the heat.
Pros: Heat is free once the water circulation system has been installed.
Cons: Installation cost is typically the highest versus other heater types, a large collection area is needed if panels will be the only source of heat for the pool – typically equivalent to the surface area of the pool, can only provide heat when the sun is out, and depending upon panel location can cause hydraulic challenges with the circulation system.