What makes a good WEF
WEF is a weighted mix at different speeds (high and low) when applicable. For a given pump design, the WEF for a two-speed pump will be higher than a single-speed pump because it can take into account the higher energy factor at low speed. In turn, a comparable VSP will have an even higher WEF, assuming it can operate below 50 per cent of maximum speed and still meet the minimum flow requirements.
The DOE does not actually specify VSPs must be used for self-priming (e.g. inground) applications. Instead, it requires a minimum WEF that, above a certain size (flow) and based on today’s technology, only a VSP will comply with. This performance-based metric encourages manufactures to continue developing more efficient products, rather than being required to follow a purely prescriptive approach.
Since WEF is the measure of energy efficiency, it makes sense a VSP would carry a higher rating than a single-speed pump. But what makes the WEF of one VSP different from another?
WEF is the overall efficiency of a pool pump which, in turn, consists of the electrical (e.g. motor) and hydraulic (wet end) system. Most VSPs in the market are based on existing single-speed designs, often with the same hydraulics but a new variable-speed motor and drive. Understandably, it is the new motor and drive that gathers attention as they, by changing speed, deliver tremendous energy savings versus a single-speed pump that runs at 100 per cent all of the time. Often, the biggest difference between individual variable-speed models is the efficiency of the wet end—how well it converts the energy from the pump’s motor into moving water.
According to the regulations, pumps will still have HP ratings, but using a different method than what has traditionally been used in most pool markets.
A horse by any other name
Pumps and motors have long been rated in terms of HP along with an associated service factor. Unfortunately, this has led to disparities within the industry where certain markets use full-rate models (higher service factor, lower rated HP) or max-rate/up-rate versions (lower service factor, higher rated HP). The DOE regulation requires manufacturers to only rate and label pumps using total HP (THP), which is the HP based on a fixed service factor of 1.0. This will eliminate the full-rate and max-rate methodology and create a consistent comparison across models.
Another new term from the regulation is hydraulic HP (HHP), which is not the same as THP as it is directly proportional to pump head and flow. Unlike WEF and THP, the DOE does not require manufacturers to label HHP on the product, since its primary use is in the calculation of the minimum WEF manufacturers must meet to comply with the regulation.
Higher efficiency does not equal limited performance. Energy-efficient vehicles may bring to mind the original hybrids from 10 years ago that may have sacrificed acceleration for the sake of energy conservation. Superior products, whether vehicles, AC units, or pool pumps, deliver efficiency and performance that complement one another instead of sacrificing one for the sake of the other.
How to use WEF
WEF is another aspect pool professionals should consider when selecting a pump for a given application. One still needs to factor in standard issues such as plumbing size, head and flow requirements, and physical footprint, the same as has always been done for both new and replacement installations. WEF allows pool pros to easily evaluate and compare the energy efficiency of pool pumps and, in turn, provide the best solutions for the consumer.
The heating, ventilation, and air conditioning (HVAC) industry has already gone through the shift to minimum efficiency requirements on how to leverage efficiency ratings. For example, a homeowner needed to purchase a new AC unit and, like many, they wanted to balance energy savings with the out-of-pocket expense. They relied on the contractor’s experience with different brands and sizing the unit; however, the contractor also provided options on different SEER ratings so the client could make an informed decision about energy efficiency.
Energy efficiency is not the only factor to consider, but it is important and should not be ignored. Pool builders, service professionals, and retailers can gain an advantage by proactively educating their customers about the new DOE standards and WEF ratings. Selling DOE-compliant pumps—many of which will be variable-speed models—is a win-win scenario for pool professionals and consumers. When it comes to selling compliant VSPs, pool pros will benefit financially because of their higher price point, while consumers will save energy and money from the increased efficiency—plus, they will enjoy other benefits, such as quieter operation. Compliance with the new DOE regulations is mandatory, so it is beneficial to prepare early and maximize selling opportunities.
Key takeaways
The DOE is regulating pools pumps, and WEF will be the primary basis for compliance and the measure of overall energy efficiency. DOE-compliant pumps provide the same installation and performance requirements needed to successfully operate pools and spas while delivering significant energy savings. Just as mpg ratings led consumers to choose more efficient vehicles, WEF labelling is expected to increase consumer preference and sales of energy-efficient pool pumps.
Scott Petty is the global product manager for pumps at Hayward Industries, and has been instrumental in the development and guidance of the new regulatory requirements along with other partnering manufacturers. For more information, visit hayward.com/regulations.
