Energy Efficient Pumps Review

Many people ask me whether they should get an energy saving pump. Here is my take on why you should or shouldn't get an energy saving pump.

The energy efficient pump

What does it do to save power?

An energy efficient pump, A.K.A. a variable speed pump, is quite similar to any other pool pump. The difference lies in the way that it can vary the speed of the pump motor to reduce unnecessary water flow and power consumption and increase it again when required. This way you don't waste electricity on a high flow rate if it isn't really necessary.

Is it worthwhile for my pool?

The simple answer: If you don't need a lot of water circulating but need to run the pool for longer hours, then an energy saving pump will reduce your power bill and help you save money, and reduce carbon emissions.

When is a high flow rate necessary and when is a decrease okay?

Suction Cleaners

Suction Cleaners such as a Kreepy Krauly, Pentair Rebel, or Zodiac G2 automatically clean the walls and floors of your pool by utilising the suction power of your pump. These can often run on lower flow rates, but sometimes that low flow rate can prevent them from working properly or stop them working all together. When considering a variable speed pump it is important to consider whether your cleaner can work effectively with the decreased flow. Many pool operators get around this issue by using robotic pool cleaners rather than suction cleaners.

If you have a suction cleaner I would recommend a variable speed pump with adjustable settings like the Viron XT or H2Flo VSP pumps. These allow you to adjust the flow rate with precision so that your suction cleaner can still work effectively, while you wind back the flow rate as much as you can to save on power and reduce your carbon emissions.

Chlorinators

These days, most pools have salt or mineral water chlorinators installed (at least here in Brisbane). Chlorinators require salt/mineral water to flow through an electrode to produce chlorine.

This doesn't require a lot of water flow, just enough to keep the electrode fully immersed in water and keep the chlorine flowing back to the pool. What it does require, is a minimum run time.

In order to produce enough chlorine to sanitise your pool you will need to run your filtration a set number of hours each day, which is determined by your chlorine demand and the chlorine output of your chlorinator.

You can work this out by dividing your daily chlorine requirement by the hourly chlorine output of your chlorinator. For example a 50,000L pool will require about 180g (100% pure) chlorine each day. If the chlorinator produces 25g/hr you divide 200 by 25 to get 7.2, the number of hours required per day.

Automatic Dosing Systems

Automatic dosing systems are very similar to chlorinators, except that they have sensors that detect the ORP & pH levels in the pool water. These are used to automate the chlorine and acid dosing. This is great for avoiding the peaks and troughs in chemical levels, keeping your pH and chlorine perfectly balanced all the time.

However, this also means that you need your equipment to be running all the time in order to detect and dose the water. This doesn't require a high flow rate, just enough for the sensors and the dosers to operate.

If you have an auto-dosing system, a variable speed pump is a very good idea and could save you thousands of dollars a year. If you have a compatible system, it's also worthwhile getting a pump that can communicate with the auto-dosing controller to automatically increase and decrease the speed, as necessary.

Filtration

Filters don't need a high flow rate to effectively catch dirt and contaminants from the water and sand/media filters actually capture more with low flow rates because smaller particles are not forced through the filter media back into the pool. However, a higher flow rate is required for backwashing and priming, and the turnover of water should be considered.

In general, I recommend running your pump long enough to turnover the complete volume of your pool a minimum of once a day. For a 50,000L pool with an Astral CTX280 pump (Flow rate 280LPM) that means a minimum of 3 hours running time. Of course that is a minimum and you should run it longer if you have a lot of leaves or other debris, the water temperature is above 24°C, or you get a lot of freshwater added. Other factors such as heavy use can also increase the need for filtration.

Chlorinator & Filter Combination

You may have surmised from above that often there is a mismatch between the filtration and chlorinator running time requirements. If you have a 25g/hr chlorinator and a 280LPM pump running you may only need to run your pump for 3 hours to sufficiently filter the pool water, but you will need to run it an additional 5 hours in order to reach the minimum run time for the chlorinator. This is where a variable speed pump comes in handy.

Of course, you could get a larger chlorinator and I often recommend that for pool owners who have temperamental suction cleaners. That said, it's usually better to run your system for more hours on a low flow setting as it keeps a steady flow of chlorine flowing into the pool for a longer period each day rather than a large dose in a short period of time.

Water Features

It's probably obvious that water features require a minimum flow rate. What that is, will depend on the type and style of water feature. Waterfalls, for example, require a high flow rate of around 200-300LPM. You may be okay with leaving your water feature off most of the time and just running it for special occasions, in which case a single speed pump will be fine. Whatever water feature you have it is important to consider the implications of a lower flow rate and evaluate whether that is ok for you.

Heating

Pool heaters usually require a long run-time but don't require a high flow rate. They will often work best at around 80-120 litres per minute. As a single speed pump usually has a much higher flow rate than this a variable speed pump could save a lot of power.

The Verdict

Your pool and existing equipment will determine whether a variable speed pump is worthwhile for your pool. If an evaluation of your pool finds that you are using more power than necessary, it could save you a lot of money on electricity. You can evaluate this for yourself or talk to one of our experts to get an evaluation of your system and see whether you could be saving money and reducing your carbon footprint.