What consumes electricity in a domestic pool?

It isn't the night-time pool lights, nor the robotic pool cleaner. A pool's main electricity consumption comes from the time the pump has to run every day to filter the water.

With a relatively low consumption, ranging from 0.75 kWh to 2 kWh depending on the power, the impact of the filter on your electricity bill becomes clear if you multiply that consumption by 8 hours a day, every day of the season. That is when a simple step, like avoiding the most expensive times for electricity, can result in significant savings. 

In other words: if the filter serves to prevent microorganisms from proliferating in the water, knowing when to turn it on helps prevent costs from multiplying on your electricity bill.

Nights and weekends: the best times to run the pool filter

When you have a time-of-use electricity tariff, the price you pay for electricity varies between different time bands:

• Off-peak hours, which are the cheapest, run from midnight to 8 am, and also include all day on weekends and bank holidays.
• Shoulder hours, which have an intermediate price, are distributed across three eriods on weekdays: from 8 am to 10 am, from 2 pm to 6 pm, and from 10 pm to midnight.
• Peak hours, which are the most expensive, apply to your consumption from Monday to Friday between 10 am and 2 pm, and between 6 pm and 10 pm, except on bank holidays.

Consequently, if you have this type of tariff, the ideal times to have an electrical appliance running for many hours are during off-peak periods: nights, weekends, and bank holidays.

The reason the price drops is that during these hours and days, demand for electricity in businesses, industries, and homes decreases, meaning the effort required to produce and distribute the energy is also lower.

If we compare one period with another, based on current prices for Endesa's Conecta 3 Periodos Tariff, we can get an idea of the total cost of running your filter this summer, depending on what time you use it:

Calculations for a pool filter consuming 1 kWh of electricity, running for 8 hours a day from June to August. Conecta 3 Periodos Tariff prices as of 17 August 2026: off-peak period: €0.094410/kWh; shoulder period: €0.117810/kWh; peak period: €0.186210/kWh.

An exception: the cost of running the filter during heatwaves

During heatwaves, especially if they are accompanied by tropical nights where the thermometer doesn't drop below 20 or 25 ºC, the model that governs electricity prices in each time band can turn against us.

The culprit for this is air conditioning. When its intensive use extends throughout the night, it generates peaks in energy demand that tend to equal, and sometimes even exceed, the generation costs typical of other times of the day.

As a result, off-peak hours, which are usually the most economical, stop being quite so cheap. In these cases, you have two possible solutions:

1. Keep an eye on how much electricity costs in each time band, which you can check on Endesa's 'Electricity Price' page, to choose the cheapest time to run the filter each day.
2. Have a time-of-use tariff that guarantees stable prices for each time band, so you aren't affected by fluctuations from one day to the next.

How to schedule your pool filter to take advantage of off-peak hours

Nowadays, most filter pumps include some kind of programmer or timer, making it easier for you to organise their running times to make the most of off-peak prices.

Once you have checked the recommendations for your filter model and the characteristics of your pool – such as water quality, capacity, water temperature, and usage – you simply need to set the pump to turn on at the times you prefer.

For example, you could run it for 7 hours split across two particularly cheap off-peak periods, meaning you will find the pool in perfect condition when you wake up each morning:

• From midnight to 4 am.
• From 5 am to 8 am.

Besides the financial savings of this night-time filtering, automation has other advantages that help you enjoy your pool more all summer long:

• The water is already clean when you start swimming.
• You avoid the noise of the motor during the day while you are in the pool.
• It helps distribute household consumption, improving energy efficiency.

When is a time-of-use tariff worthwhile if you have a pool?

Generally speaking, the time-band model is the most convenient option for homes with a private pool. The main reason is the cumulative savings throughout the summer, by moving the long filtering times to the cheapest hours and days of the week.

But beyond the pool, this type of tariff gives you the opportunity to pay less for electricity when you get out of the water. The trick is to shift the use of the most energy-hungry appliances to off-peak periods, all year round:

• Dishwasher.
• Washing machine.
• Tumble dryer.
• Immersion heater.
• Oven/hob.
• Electric car charger.

This way, you harness the potential of weekends, bank holidays, and the cheapest hours on weekdays to reduce the cost of all your bills.

There is no need to run the filter while you are swimming

Reading this article, you might be wondering about one of the most common questions regarding pool filters: Shouldn't it be running while you're in the pool?

The answer is no, even though it is a very common habit. In reality, pool water needs to be filtered with a frequency that is usually daily, and the effectiveness of that purification depends on the amount of time specified by the manufacturer. Therefore, it is neither necessary to keep it on all day – except during very intensive use – nor to do so while you are swimming.

For this reason, filtering at night is just as effective as doing it during the day. But there are two key benefits:

1. At night, you can save almost 50% on the price of the electricity consumed by the filter, compared to peak-time prices.
2. The effectiveness of the purification is combined with energy efficiency, spreading your household consumption more sustainably and also helping to reduce the overall demand for energy generation during the central hours of the day.

Frequently asked questions about saving on your pool filter

When is the cheapest time to run the pool filter?

Between midnight and 8 am, as well as all day on weekends and bank holidays, are the ideal times to take advantage of the cheaper prices during off-peak hours.

How long should the filter pump be left on each day?

Usually between 6 and 8 hours a day, depending on the manufacturer's recommendations and the volume of water in the pool. However, depending on the intensity of use, the ambient temperature, or the amount of dirt in the surrounding area, it might be advisable to run the filter for longer on some days.

Can you use the pool with the filter switched off?

Yes, absolutely, provided the water has already been filtered beforehand. For example, you can have the pump on during the night, meaning you won't need to turn it on while you are using the pool during the day.

How much does a timer for a pool filter cost?

If your filtration equipment does not include a timer or programmer, the prices for these devices range between €10 and €30. There are also more expensive options, especially for models with more smart automation features or remote management from a mobile phone.