I installed a Hayward 110K BTU heat pump. The temp outside was 70, water temp was 51. After 5 hours, the water temp only came up to 52 in an inground pool that is 16X32. Is this normal? I thought it would heat approximately 2 degrees per hour. The nights are still getting down into the 40's.

Do heat pumps only work when it is warm out?
How can I tell if it is heating properly?

Marc Miller
Usually the best way to see if your heat pump is working is to measure the air coming off the top of the heat pump. It should be about 10 degrees colder than the outside air. That can change depending on humidity, air temperature etc, but it is a good place to start. A bad place to start is to feel the water coming into the pool. Sometimes if you have a powerful water pump the heated water coming into the pool might only be 1 degree warmer than the pool water so it can be impossible to tell with your hand that the heater is working. I don't like to look at a pool after 5 hours. Let the heater run for a couple of days and then see what is happening. A few hours here and there you just never know. Maybe there was a lot of wind? Maybe it rained for an hour, who knows. Just make sure the air coming off the top is colder and let it run. The start and the end of the season you will always see the longest run times. Make sure you use your pool blanket when the nights are below 65 degrees or any temperature if you want to save the most money. Heat pumps don't work when it is only warm out as then there would be no point in having a heater. Just have patience.
Please let me know if you have any other questions.
Marcus Miller
1 800 741 9956
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