Can I Leave My Pool Heater on Overnight

Can I leave my pool heater on all night? It’s a buzzing question to the pool owners who want to swim in the morning. On a frigid day of winter, it’s a must to keep the pool water warm. And a heater comes into play to heat the water.

When it comes to leaving the pool heater overnight, you should consider multiple things like the climate where you live, whether you put a cover or not, and others. Indeed, it’s typical to give a definite answer to your question. 

In short, the answer will be both Yes and No. To learn when you can run the heater on all night and when you can’t, continue to read. 

Can I leave my pool heater on all night?

Whether you should leave the pool heater on all night or not depends on your usage, plan, and whether you have a pool cover or not. Also, the climate affects the heating process. 

If you live in a colder area and leave the pool uncovered, the temperature of your pool drops to 4-5 degrees. Some pool heaters will require 24 hours to reach the desired temperature. If you want to use your pool the next morning, turning the pool heating at night will not bring any changes. In simple words, you can’t get warm pool water according to your comfort level. It just adds electrical costs as evaporation and heat loss will occur at night if you don’t have a cover. 

On the other hand, you can leave your pool heater on all night if you have a solar pool cover. The solar cover or blanket will stop evaporation & heat loss by absorbing the heat from the sun. Later, it will transfer the heat at night to keep the pool temperature a bit warm. If you run the heater overnight, no heat loss will occur and you will get the desired temperature level for swimming in the morning. 

When and Where You Can Run Your Pool Heater at Night

It’s a common misconception that you can’t run your pool heater at night. But, running a pool heater overnight varies from place to place as well as depends on the existing facilities. Can you run your pool heater at night on below certain conditions to prevent spending a fortune:

  • If the difference between the ambient temperature at day and night is not significant.
  • If you use a solar blanket or any other pool cover the retain the heat. Because water evaporation is the single largest reason for loss of heat in the swimming pool
  • It is okay to run a pool heater at night if it does take too long to heat a pool. So, you need to determine, how long does it take to heat your pool.

It’s certainly not cheap to run a pool heater 24/7. Your bet is to purchase a quality solar pool heater or solar blanket and energy-efficient pump to scale out your utility cost. Furthermore, it will increase your heating efficiency.

How Much Heat Does A Pool Lose Overnight?

It depends on whether you cover the pool or not at night. Your swimming pool will lose 4-5 degrees if you leave the pool uncovered. However, you can reduce the heat loss by 50% if you put a solar cover on the pool. It means the temperature of your swimming pool will drop 2-3 degrees if you leave the cover on at night. 

Can you leave your pool heater on all the time?

Yes, you can leave your pool heater on all the time, but you should consider the following points. 

  • The type of pool heating system (heat pump or heater) you have
  • Does the heating system have a temperature controller?
  • The filtration or circulation pump is on or off

If you have a gas or electric pool heater, it will skyrocket the operating cost if you run it all night. On the other hand, a heat pump is the most energy-efficient option if you want to run it for a long period. It is because the heat pump heats slowly but maintains the pool temperature level very well. 

You should also consider whether the heating system has a temperature controller or not. If not, you should install a temperature controller which will turn the heating system on and off according to your need. 

Lastly, you should also keep the filtration pump on when you heat your pool. It helps to circulate the water and convect the heat throughout your pool optimally. And running the heating system and pool pump at the same time will increase the pool heating cost. 

Indeed, the answer to your question will depend on the three points we mentioned. Otherwise, there is a chance of overheating of the heater to damage the system. 


In conclusion, it is wise for you to leave your pool heater on all night if you have a pool cover and the surrounding temperature difference between day and night is not huge. It will prevent evaporation and heat loss, so, you don’t have to worry about excess energy costs.

On the other hand, if you don’t have a pool cover, don’t run the pool overnight. It doesn’t raise the pool temperature.

Before making the final decision, on whether you should run the heater at night, you must check your local utility guideline and consider the safety measures.

Leave a Comment

Your email address will not be published. Required fields are marked *