What Is the Best Time of Day to Run a Pool Pump?




I gave very little thought as to when to run my pool pump when I first had my pool and just let the timer run as it had been set by the previous homeowner. Since then I have investigated the subject further and made some adjustments.

There are many points of view as to the best time of day for pool owners to run their pool pumps. Some say it should be during the day while others say it is better at night. Each has its merits but there is no absolute winner but this is how to decide.

Key Takeaways

The best time of day to run a pool pump is:

  • during the day in the summer to keep the pool surface clear of bugs and debris
  • overnight during the winter (assuming you do not need to winterize your pool) as swimming will not be taking place and electricity prices may be lower

I will try to make things a bit clearer so you can make up your own mind about the best time for you to run your pool’s filtration system.

best time to run pool pump in summer

Is it better to run a pool pump at night or day?

Running a pump in the daytime

The arguments for running the pool pump during the day are mainly as follows:

  • Algae grow quickest when the sun is at its strongest so it makes absolute sense to run the pool pump when the sun is at its strongest, ie. during the period over midday. So if you need to run the pump for 8 hours each day to ensure the total volume is filtered then you should run the pump from 8am to 4pm.
  • The pump operates the skimmers, which, in turn, remove all of the floating debris such as leaves and insects. So ideally you want the skimmers to be working at a time you are likely to be swimming otherwise you will be getting all sorts in your mouth while swimming.
  • The UV in sunlight degrades chlorine so there is a larger demand for it during daylight hours. Running the pump helps to stop this from happening by dispersing it around the pool. This saves money on chemicals that running at night would not.
  • If you have solar heating, as I do, then there would be little point in having them if you didn’t run the pool pump during the day when the sun is shining.

Running the pump at night

There is really only one argument for running the pool pump at night rather than in the daytime and that is all about energy savings and reducing your electric bill. Many countries, states or areas give cheaper electricity at certain times of day, generally at non-peak times when electricity demand is lower. This is normally during the night.

Off peak hours electricity rates can be as little as 25% of the peak hours electricity rates in some countries. Some electricity suppliers have three-tier rates which include a “shoulder” period between low and peak rate hours. Electricity is cheaper than the peak rate but higher than the off-peak rate then.

So if you run your pool pump during those hours then your electricity bills will be lower. But you should balance this with the reasons to run the pump during the day which may well outweigh this benefit.

You can call your electricity supplier to find out if you are eligible for cheaper electricity at certain hours, and to find out how much cheaper, so you can work out how much you are likely to save.

Running overnight after shocking

The only time I generally run my pool pump overnight is when I have shocked the pool, which I do in the evening. The shock then gets properly distributed around the pool and isn’t dissipated by the sunlight.

So what is best?

Since the above all have their merits then there may be good reasons for you in having your pool pump running both during the day and the night. So perhaps it would be best to compromise.

It may be feasible for you to consider running the swimming pool pump for half the time it needs to run daily during the middle of the day, when the sun is at its hottest, say 10am to 2pm, and the other half of the time at night, say 1am to 5am.

It is easy to experiment to work out what is the best time of day to run your pool’s filtration system in your situation, so try some different settings on your timer. You will soon find out what works best for you.

What do I do?

I do not receive discounted electricity at night so trying to save money by doing some nocturnal pumping is not an option. I generally run my pump from around 10am to 6pm in summer. This works well for us as we tend to swim in the late afternoon most days during our swimming season, which runs from March to November now that we have a solar pool cover.

These are my thoughts on having a solar pool cover.

In the winter I normally reduce the time to around 5 hours and run it from 11am until 4pm which saves some electricity while still filtering the water.

Is it OK to run pool pump 24 hours a day?

Yes it certainly is and in an ideal world that would be the case. If you could run it 24/7 year-round then that would certainly keep your pool as clean as it could be.

But for most pool owners this isn’t really practical as the cost would be prohibitive and actually, the pool pump would wear out quicker so replacing it would be another additional cost.

For more information then check out my article “how long should I run my pool pump?”

Also you may wonder whether the pool pump should be running when you swim so this article will answer that – Do you run the pool pump while swimming?

what is the best time of day to run pool filter

How long should I run my above ground pool pump?

There is no real difference between running an above-ground and an in-ground pool pump. In both cases, they should be run for long enough to circulate the entire volume of water in your pool. Many above-ground pools are smaller than in-ground pools so the volume is likely to be lower. However, quite often, the above-ground pumps have a lower flow rate so may well need to run for a similar amount of time.

Whether you run the above-ground pump during the day or at night follows exactly the same criteria as in the earlier section.

Pool Care Handbook and Video Course

When I bought my house with a swimming pool, I knew absolutely nothing about pool care. I just winged it for a while, making many mistakes along the way.

Fortunately, I was recommended Swim University’s Pool Care Handbook and Video Course. I bought it and it was an absolute game-changer.

It was the best money I spent that year. I learned everything from basic cleaning to advanced troubleshooting. Swim University offers a no-quibble refund policy too so what do you have to lose?

How long should I run my pool pump in the winter?

This depends on the climate you live in.

If you live in a temperate region, where temperatures do not drop below freezing, there is no danger of the water in your pool and pipework freezing. In this case, you can let it run every day to circulate the water.

This is true for where I live so I run it for fewer hours in winter. Normally this is around 5 hours which I find is sufficient to stop algae from forming so I don’t end up with a green pool to deal with. Obviously, I also add chemicals to prevent algae too.

If you live in a cold region where freezing temperatures are frequent then things become a little more complicated. If you just leave the pump on a timer and the water in your pipes freezes then your pump will probably be damaged. In this case, it is better to put the pump on and off manually when the temperatures are a bit higher.

Winter normally brings more rain so you may find my article Should you run a pool pump when it rains useful.

Do you have to run pool pump in winter?

best time of day to run pool pump
Hopefully your pool will not end up like this

If you live in a cold climate so you need to winterize your pool then you will not need to run the pool pump during the winter.

If you do not winterize your pool and you do not run the pool pump in winter then in all likelihood you will have a very dirty and green pool to deal with in the spring. This is not the end of the world but does require more work to get it ready for swimming of course. You may think that the money saved in not running the pump is worth it so that is a decision for you.

My top 3 pool cleaning tools

These are the pool cleaning tools I have found the most useful since I have had my pool.

Step and corner vacuum brush

This is a really useful tool for getting into the areas that a standard vacuum head simply cannot reach. Aquatix Pro Pool Step & Corner Vacuum Brush

Leaf rake net

If, like me, you get plenty of leaves at the bottom of your pool then a good leaf rake/net is a must. The Stargoods Pool Skimmer Net gets under the leaves easily.

Robotic pool cleaner

These are quite expensive and it was a number of years before I bit the bullet and bought one. I have never regretted it. The Dolphin Nautilus CC Plus is the most recommended pool cleaning robot on all of the pool forums. It not only cleans the bottom of the pool but also the sides and the waterline.

Is it OK to turn pool pump off at night?

Absolutely, you do not need to run a pool pump at night at all. However, if you shock your pool in the evening then the pump should run overnight to distribute the shock.

Is it better to run the pool pump at night or day?

While running a pool pump at night rather than during the day may save on energy bills, it will not make swimming as pleasant as the skimmers will not be in operation to remove bugs and other floating debris.

Does running pool pump at night cool water?

A pool is likely to be cooled to some extent when the pool pump is run at night when the air is cooler. This would be particularly true if you have solar pool heating as the solar sheets will act more like a refrigeration unit.

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