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The Home Depot

Why is My Hot Tub Heating so Slowly?

Pro Referral > Home Guides > Pool and Hot Tub > Why is My Hot Tub Heating so Slowly?
Why is My Hot Tub Heating so Slowly?

Hot tubs are a great way to relax and unwind at the end of a day. Depending on the size of your family and the space available, you can get hot tubs that seat two comfortably or provide sufficient space to host a small party. Either way the water in the hot tub has to be at the right temperature for maximum enjoyment. Hot tubs are typically kept heated continuously. However, the water in the hot tub needs to be empties and the tub cleaned periodically. When a hot tub is refilled, it should take over night to heat up. Some outdoor hot tubs take up to two days to heat up in the summer. If your hot tub is slow to heat up, you need to examine all the things that could cause this problem.

  1. 1.Filter

    Frequently, the hot tub takes longer to heat up not because of a heating element problem but because of clogged filters. The filters of the hot tub need to be cleaned regularly, depending on usage and the manufacturer specifications. Before cleaning the filters, you need to switch off the hot tub and remove the filters. The filters can either be soaked in a special solution for 24 hours or you can use a quick cleaning solution that is sprayed on the filters. The filters should then be washed and dried completely before being fitted into the hot tub. Many people find it convenient to have a spare set of filters that can be placed in the hot tub while one set is being washed and dried.

  2. 2. Cover

    A hot tub will be surrounded by an insulating cover to help it retain the heat. If this cover is damaged or has slipped, the water in the hot tub will cool more quickly and take longer to get heated in the first place. Examine the cover around the hot tub for cracks or gashes, and either replace it or mend it. This should ensure that your hot tub gets heated quickly.

  3. 3. Thermostat

    Another reason for the hot tub heating up slowly could be a malfunctioning thermostat. Sometimes, the thermostat needs to be reset to ensure that the water in the hot tub heats up more quickly. At other times, the thermostat needs to be replaced. When the thermostat is malfunctioning, it assumes that the water is hot enough and switched off the heating element, leading to not so hot water. A thermostat that works properly will eliminate this problem.

  4. 4. Hi-Limit Switch

    Every hot tub has a hi-limit switch that cuts of power supply to the heating element to ensure that the water temperature in the hot tub does not exceed tolerable limits. This is a safety precaution to ensure that people do not inadvertently burn themselves. Sometimes, the hi-limit switch can trip, preventing the hot tub from heating up to quickly. Simply, reset the hi-limit switch by pressing the red button to eliminate this problem. However, if the hi-limit switch trips frequently, you need to identify the cause behind this and rectify that.

  5. 5. Daily Cycle Not Running Long Enough

    In order to keep the water in the hot tub heated for when you need it, the daily cycle has to run long enough each day. This daily cycle will take care of the filtration and heating. All you need to do is reset the clock to ensure that this cycle is longer for the water in the hot tub to heat up more quickly.

A hot tub is a welcome addition to most homes. Every family member can enjoy some time each day in the hot tub to unwind. However, the pleasure that a hot tub can provide is diminished if the water takes long to heat up. While the heating element is not usually to blame for a slow heating hot tub, even identifying and fixing the other causes can be tricky as a hot tub combines water and electricity. Instead, it is often safer and easier to rely on an experienced hot tub mechanic to identify and fix the cause of the slow heating hot tub.


A hot tub, like other gadgets and appliances that promise convenience and comfort, can become a trouble spot if it does not function as expected. However, regular maintenance and proper servicing can ensure that you and your family derive many years of relaxation and fun from the hot tub.


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