Hot tubs, well all efficient hot tubs (likes ours 😉) are designed to retain as much heat as possible to make them running costs as low as possible. This of course, makes perfect sense.
But during warmer weather, you might experience your hot tub going a few degrees over it’s set temperature. But don’t panic; it’s not a problem with your hot tub.
This is often referred to as ‘Thermal Creep’ where the temperature of the hot tub keeps creeping up as it has no way to let the heat escape.
So why do I get summertime overheating?
The leading cause of going over temperature is down to the electric motors. These are used to pump the water around the hot tub for heating, filtering and powering the jets. When the electric motor runs, it generates heat. The emitted heat is then transferred into the hot tub water, raising its temperature over the desired temperature.
This is exaggerated in the summer as we usually run our hot tub a little cooler.
Did you know it’s not uncommon for a hot tub to get to 25° – 30°c just from heat from the motors and without the heater even being on!
So why is the pump running if the water doesn't need to be heated?
Hot tub water needs to be circulated and filtered. On average a hot tub will need to filtrate for around 2 to 4 hours a day. So during this filtering periods, your water will be absorbing the heat given off by the pumps.
Secondly, you might find your hot tub overheating because of its location. If set in a particularly sun-exposed area, then the spa will find it harder to dissipate heat.
So what can I do to prevent my hot tub from going over temperature in the summer?
To cope with overheating some control systems will shut all filtering down until the temperature has dropped. Others will reduce filtering times.
Open the cabinet air vents
Reduce filter durations
During the warm spell, reducing your filtering durations can also help prevent your hot tub from going over the desired temperature. Don’t forget to put the filter settings back to normal when the weather has cooled down.
Some hot tub control systems also allow you to set what times the filtering is carried out. Changing the filter times to run at cooler times of day can also help.
Open your air controls
Opening the air controls for your jets will draw in the warm air from inside the hot tub, allowing it to dissipate quicker. If you do this keep an eye on your Total Alkalinity level as running air through the water can lower this.
Prop open the cover
Prop open the cover with something like a towel or tennis ball will allow excess heat to escape.
Remove some insulation
If you hot tub is fitted with a perimeter insulation, you might be able to remove some of this during warmer months. In worst cases, you might need to open one of the access panels on the side of your hot tub to allow for heat to escape.
What temperature should I run my hot tub in summer?
There is no right answer to this, it comes down to personal choice, but in many cases, users will drop the temperatures to make bathing more comfortable. Ranges from 32° to 37°c are not uncommon.
We do hope we’ve answered all your questions on overheating hot tubs in summer, of course, if there is anything we’ve missed or you have any questions, feel free to ask.
Enjoy the weather and happy tubbin’.