Pool Pump Energy Costs
There are three types of pumps for residential swimming pools.
The most common is the standard single speed pump.
The drip proof motor is rated for continuous use. Cooling air is brought in from the front underside of the motor and exists out the back. It’s a good idea to inspect and clean the vent holes yearly.
Most of these pumps are oversized for the pools. A modern ¾ hp pump is more than sufficient to circulate the water in a residential pool 2.5 times in 24 hours. You will only need a 1hp, full rated, pump if your pool is bigger than a 20’x40’ pool or 110,000 litres. The higher the horse power the more it costs you. A 1hp, full rated, pump costs about $700 to run for a 5 month season, while a ¾ hp, full rated, pump will cost about ¼ less or $525.
Two speed pumps are becoming more common.
They allow you to run the pump at half speed. A 1hp max rated (equivalent to a 3/4hp full rated) pump, running at ½ speed, will cost about $228 per season. By setting up a timer to run the pump at low speed when hydro is more costly and running on high speed when it’s cheaper you will have considerable savings. You do need to run the pump on high speed in order to vacuum, heat the pool and have 2.5 time water turnover. The low speed will not be able to activate the pressure switch on the heater or run a suction side pool cleaner.
The latest in pumps are the variable speed permanent magnet motors.
The efficiency of the above motors are about 70% while the permanent magnet motors are about 90%. These motors are also sealed. The cooling air is run on the outside of the motor, not inside as above. This means that the motor will last longer as you do not have any ambient air, as in a shed with possible open pool chemicals, blown through the motor and rusting the rotor of the motor causing it to seize. The advantage of a variable speed motor is that you can set it for your specific pool requirements and not more. You can also set it so that it will run the heater and pool cleaners. Some of the more expensive pumps will have built in clock timers so you can set one speed to run during daytime and another at night. You can also set it to run waterfalls or overflow spas reducing the need for additional pumps.