There is a lot of confusion among pool owners about how many hours to run the pool pump and filtration system each day. Do you run it during the day or night or both? Do you vary the operating time from one season to the next? And how long do you run the salt water chlorinator?
A swimming pool pump does not have to be operated continuously all day and night for a backyard pool. The number of hours you run your pool pump each day depends on several factors. You need to know the volume of water in your pool, the capacity of your pump and how long it takes for your filtration system to turn over the entire contents of the pool. If you have a saltwater swimming pool the chlorinator unit will need to be operated for a minimum number of hours each day to generate enough free chlorine to sanitize the pool water and maintain a free chlorine level between 1 and 3 parts per million. If you have a heated pool the water heater will need to be operated for a minimum number of hours each day to heat the pool to the desired temperature.
Table of Contents
The Filtration System
One of the most important aspects to keeping pool water clean is circulate the water around the pool. If the water is left stagnant it will quickly become a breeding ground for algae and bacteria.
The filtration system draws water from the pool and pumps it through a number of appliances to clean and process the water. The pump and filter must run long enough to process all the pool water each day. That is, the pump must turnover all the water in the pool on a daily basis to ensure the pool water is clean. Normally, a pump is chosen for your pool with the capacity to filter all the water every 8 hours.
The pool water is pumped through the following appliances:
Pump Basket
All pool pumps have a built-in pump basket. The basket captures medium-sized items of debris from the water before it’s drawn through the pump and into the filter. This prevents the pump and filter clogging quickly with large items of debris.
The skimmer basket captures all leaves, insects and prevents large items from being sucked into the plumbing. You don’t want floating toys or other objects blocking the plumbing.
Filter
There are two main types of filter – cartridge or sand.
It doesn’t matter which filter you have as each have advantages and disadvantages over each other. The important thing is the filter has the capacity to clean all the water in your pool every 8 hours. Regularly clean and maintain the filter to ensure the correct and efficient operation of the filter.
Heater
Many pool owners install a water heater to extend the swimming season and make swimming at night more comfortable.
If you have a pool heater it must be installed after the outflow of water from the filter and before a saltwater chlorinator. The heater can either be a heater unit or a heat pump. A heater unit simply runs water through heated copper piping to increase the temperature of the water. A heat pump operates like an air conditioner or refrigerator in reverse where the water is heated rather than cooled. It works on a different heating principle by compressing and decompressing a refrigerant to exchange cold with heat. When the liquid refrigerant is allowed to expand or decompress into a gas it absorbs the surrounding heat. When the gas is compressed back into a liquid it releases heat.
Chlorinator
If you have a saltwater pool the last process is to pump the water through a saltwater chlorinator. The chlorinator must be installed last after all other appliances. The chlorinator is a clear electrolytic cell. It works by running a very low voltage but high electric current is through the saline water to produce chlorine. The free chlorine immediately binds and destroys algae, bacteria, viruses and other contaminants. The chlorine reverts back to dissolved salt completing the cycle. The filter traps all the destroyed contaminants making your pool safe, clean and clear.
Please read our article on How to Clean a Saltwater Chlorinator Cell
Choose the Right Type of Pump
Years ago all swimming pool pumps used to be single speed motors. These pumps are outdated and should be replaced with a new dual or variable speed pump. We recommend variable speed pumps.
Variable Speed Pumps
The variable speed pump technology costs significantly less to operate. The pumps operate at lower revolutions per minute (RPM) than other pumps giving more filtering capacity while consuming less electricity. These motors are built with ultra-efficient permanent magnet motors, as used in advanced hybrid cars which are dramatically quieter than old single speed pumps. You can run the motor at night without keeping everyone awake.
The pump saves power by matching the motor speed to your pool’s filtering requirements. This results in better water quality, superior filtration and lower operational costs by operating longer, at lower speeds.
Choose the Right Size Pump
If you have the right size pump for your pool it should filter all the water every 8 hours. This is referred to as the turnover rate of the pump.
Turnover Rate
Most pool pump capacities are rated by gallons (litres) per minute.
Assume we want to run the pump for 8 hours per day.
Divide the pool’s volume by 8 to get gallons (litres) per hour
Then divide by 60 to get gallons (litres) per minute.
Capacity (GPM or LPM) = pool volume / (8 x 60)
Example:
Pool volume = 50,000 litres
Capacity = 50000 / (8 x 60) = 104 litres per minute (LPM)
Now select a pump with at least the capacity to turn over all the water in your pool in 8 hours.
Note: Most new swimming pool pumps will easily turn over all the water in a backyard pool within 8 hours so there’s really no need to worry too much about the technical specifications. The new pumps are very powerful, quiet and energy efficient.
Choose the Right Size Filter
The filter must match the size of your pool so the larger the volume of water the larger the filter required. That was easy but that’s not the entire story.
The real driver for most existing pool filtration systems is the size of the plumbing pipes. If you have narrow pipes matched with a small filter and pump motor you cannot replace the pump with a huge motor that is too powerful for the size of your plumbing and filter. The water pressure may damage the filter and plumbing.
Choose the Right Size Water Heater
Lastly, the size of your water heater must match the volume of water in your pool. You are wasting your time and money on an under-sized water heater.
Most water heaters only heat the water at a rate of 1C per hour so if your water is cold at 15C and you want to heat it to 23C that will take 8 hours of pump and heater time every day. The other thing to consider is that if you want to swim in the morning your pump and heater would need to run all night or at least 8 hours before you want to go swimming.
And you would really need to install a pool cover at night to retain the heat. There’s no point heating the water at a rate of 1 C per hour when the water is cooling at night at 0.5C per hour.
When to Run the Pool Pump
Your decision as to when you set the timer to operate our pump will determine how many hours to run the pool pump and how much the power will cost . If you run the pump at off-peak times you will save on your electricity bills.
Peak Power
Peak electricity usage varies on location, season and climate but generally the following are considered peak times:
6am to 9am (small peak)
4pm to 8pm (large peak)
There is a small peak in the morning when people get up, use the bathroom and have breakfast before going to work. They will consume electricity turning on lights & heaters, using hot water and cooking food.
The large peak of power usage is in the late afternoon and evening when people come home from work turning on lights, TVs, air conditioners, heaters, cooking appliances and use hot water.
Off Peak Power
The opposite of peak power is off peak power – 8pm to 6am and 9am to 4pm.
These are the times when you want to run your pool pump. You would need an electrician to install a separate circuit and meter for the pool pump so the electricity company can charge you at off-peak electricity rates.
Recommendation: Run the pump from 9am to 3pm (6 hours) and 8pm to 10pm (2 hours). These 8 hours will not only save you money, ensure the pool is adequately filtered and sanitized but also not annoy your neighbors with pump noise in the middle of the night!
Remember that if you are adding shock to the pool you need to add it to the water after sunset for maximum effectiveness otherwise it will be burned away by the sun. So you would want to adjust your pump times to ensure the shock chemical is fully mixed and circulated. Most other chemicals can be added at any time.
Our Environment
Please try to reduce how many hours to run the pool pump during off peak electricity periods. Try to run your swimming pool pump during off peak electricity periods to help reduce the overall electricity demand in peaks times. If everybody works together to reduce peak power usage we don’t need so many polluting power stations on our planet! These power stations are one of the main causes of air pollution which contributes to climate change problems. When you run your pump at the daylight off-peak times (9am to 4pm) the electricity can be generated from solar energy and not carbon-based fuel sources such as coal, oil & gas.
How Many Hours to Run the Pool Pump in the Off Season
Do you need to filter all the water in your pool each day?
During the summer when the pool has the highest usage you will need to turn over all the pool water each day. To achieve this operate the pump at least 8 hours. Also, in the summer you will need to generate more chlorine to adequately sanitize the pool water.
During the off season, when the pool is not used, most pumps only need to be operated for half the time. There is less heat and sun to burn off the free chlorine and the pool water doesn’t become so contaminated because there is no one swimming. If you use a pool cover it will keep the pool cleaner allowing less daily filtration. So in the off seasons of late fall, winter and early spring you can reduce the daily pump time to half or three quarters of the summer pump time, say 4 to 6 hours daily.
Recommendation: Run the pump from 10am to 1pm (3 hours) and 8pm to 10pm (2 hours).
Conclusion
I hope we have softened the confusion around how many hours to run the swimming pool pump and filter. You don’t need to run the pump continuously for a backyard pool that’s just wasting power and wearing out your filtration system. The pump only needs to operate enough to filter most of the pool water each day and produce enough chlorine from the saltwater chlorinator to sanitize the pool. Typically, the operating time is about 8 hours per day split into two 4 hour sessions in off peak electricity periods.