Heat Pump Pool Heaters

Heat pump pool heaters can solve two problems common to indoor swimming pool applications. The unit can provide the facility with economically heated pool water and reduce the pool area humidity, which not only increases the comfort of the patrons but helps reduce mildew and the maintenance problems and costs associated with excess moisture in the air. Warm, humid air fogs windows, causes dripping ceilings, peels paint and rusts metal. All these things increase operating costs. The humidity problem has typically been solved by exhausting the moisture-laden air with large fans and replacing it with drier outside air. In the winter, the cost of heating this air can be exorbitant. The heat pump reduces the need for winter outdoor air. For winter use, an air-to-air heat recovery unit - such as a heat pipe - is also recommended.

Heat pump pool heaters typically operate in two modes - summer and winter. During the summer, the unit provides cooling and dehumidification along with hot water. An economy cycle is suggested for nights and early morning, where outdoor air is circulated and exhausted.

Coefficients of Performance assuming 75°F air enters the heat pump and a 80°F pool water temperature typically run about 3.4, which means the heat pump heats the water 3.4 times more efficiently than a traditional electric water heater.

During the Spring and Fall, the combined functions of the heat pump and air-to-air recovery will usually satisfy the structure's water heating, space heating and cooling, ventilation and dehumidification needs. During the winter, the cycle can be set either for all water heating or both water and air heating. The heat pump will usually provide all the water heating and up to 60 percent of the space heating.

Heat pumps are sized primarily on the basis of pool surface area for outdoor swimming pools. A pool cover is usually a good investment since it reduces pool evaporation. Outdoor spas are sized according to the number of gallons of water; again a cover is recommended. A 5 horsepower heat pump can heat an 1100 square foot covered pool or a 600 to 800 square foot pool that is not covered. The same unit can heat a 1400 gallon tank to 104°F.

One potential limitation is that there are relatively few equipment suppliers. Also consider the availability of parts and service in the purchase decision. Due to the corrosion elements present, such as chlorine, these heat pumps should be designed specifically for pool operation by a supplier with a good reputation, and not be just an adaptation of a unitary heat pump.