Letter to the Editor: Additional benefits of robotic pool cleaners — reduced water consumption and chemical use
As Pool+Spa published early in 2016 (‘Pool cleaners and energy use’), an independent electricity company, PG&E, undertook an analysis to compare the energy consumption of different types of pool cleaners over the course of the year. Needless to say, robotic pool cleaners consumed much less energy, being 65% more efficient to run than the next best option of manual cleaning (excluding labour costs) and a whopping 93% more efficient than the least efficient option of booster (pressure) pump cleaning.
Apart from energy efficiency gains, there are many other benefits of using robotic pools cleaners that also reduce the operating costs and the hassle of maintaining a swimming pool. Putting aside the excellent cleaning results for one moment, a good quality robotic pool cleaner will also deliver savings in other areas such as reducing water consumption and lowering the need for chemical use to balance water.
Much like all pool cleaners before PG&E undertook their pioneering pool cleaner energy consumption study, there is no official or standardised measurement for water saving and reduced chemical usage. Perhaps this is because all pools vary to some degree in the vagaries of operating costs and maintenance required. However, it is still possible to conduct some investigation to reach conclusions about other savings.
Let’s break it down and analyse the two factors: reduced water consumption and reduced chemical usage attributed to using a robotic pool cleaner. Keeping in mind that all pools do vary to some degree, let’s focus on the principles of operation and maintenance to open a conversation about best practice to find a way the industry can standardise measurement and calculation of savings achieved.
Robotic pool cleaners reduce water consumption
Reduced water consumption is achieved as robotic pool cleaners collect dirt and debris independently from the pool’s main water filtration system. Everything collected by the robot is stored in the cleaner’s internal filters and is removed from the pool system with the robot at the end of each cleaning cycle or when the canister is full.
Compare this to the popular suction pool cleaner still currently used by most pools in Australia. Suction cleaners deliver all dirt and debris directly to the pool’s main filtration system with the larger debris caught in the skimmer box basket. The smaller debris remains in the pool filter (and the pool system) building up until the pressure reaches the point where backwashing is required. Suction cleaners, when continually connected, can spend eight hours each day delivering debris to the main pool filter.
A view may be that for every two backwashes, where a robotic pool cleaner is used, there would be an extra backwash required for a pool where a suction cleaner is used. Based on this, using a robotic cleaner may save you 33% or more of your backwash water, which adds up quickly over time.
Along with reducing backwashing needs, robotic pool cleaners also work to improve a pool system’s hydraulic flow with better water circulation and pool turnover times. Reduced pressure build-up in the main filter system is the contributing factor for improved circulation that also allows the pool equipment to operate more effectively (pump, filter and chlorinator). This creates an environment for a healthier pool and leads into the next benefit that robotic pool cleaners contribute to: reduced need for chemical usage.
Robotic pool cleaners reduce the need for chemical usage
So now the pool pump is circulating water more effectively (less pressure = more flow). Add to this that the robotic cleaner is circulating water throughout the pool — usually at rates of around 17,000 L/h. The robotic pool cleaner is picking up the larger and smaller debris, doing the heavy lifting of removing organic and particulate matter instead of the main filter system and sanitation agents. And, most importantly, the debris is removed from the pool system. The robotic cleaner can scrub pool floors, walls and waterline, providing a thorough clean. The main filter system is now free to collect the tiny microscopic particulate matter. Combined with the regular cleaning cycles of the robotic cleaner, most of the dirt and debris is no longer breaking down inside the pool burning out chlorine and adversely affecting pool water chemistry and balance.
Again the example is drawn against suction pool cleaners, simply due to the fact they are one of the most common types of pool cleaners in Australian backyards. Suction cleaners utilise the pool skimmer box as a connection port to the pool pump, effectively rendering the skimmer useless, and forcing debris to stay in the pool system, waiting for the debris to stay in the pool, slowly sink and eventually get collected — all of this requires more chemicals to control and keep the pool water chemistry in balance. By applying common sense it is easy to understand how robotic pool cleaners help reduce chemical usage in this way. The faster removal of dirt and debris means less chlorine is needed by sanitising the decomposing organic matter and fewer chemical by-products are produced.
So the question is — how much less chemical usage is achieved and how can this be measured, standardised and quantified to educate or inform consumers? How to measure chemical usage when each pool has different bather loads and conditions? It is a challenge!
Regardless of having no meaningful way to quantifiably measure, what becomes absolutely clear is that regular effective pool cleaning by robots reduces the ongoing costs of pool control and in the long run benefits all aspects including water clarity, pool balance, bather comfort and of course the visual aspects of owning a clean sparkling pool that is inviting to swim in.
The other undisputable fact is that robotic pool cleaners make cleaning a pool simple and easy. Good quality cleaners also deliver effective cleaning and scrubbing of floors, walls and waterline. Clear benefits of reduced power consumption, reduced water usage and reduced chemical usage are plain to see, but the big questions is how the second two can be measured accurately.
If you have further thoughts and ideas on the concepts presented in this article we would enjoy the debate and discussion.
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