The most important part of any pool is the pump. It’s the epicenter of how your pool functions. A pool cannot have a proper water balance, and pool testing cannot be done without water circulation.
A pool pump circulates water from the pool into the filter, heater, or other pieces of equipment and then returns cleaner water into the pool for a better swimming experience. An easy analogy is to think of the pump as the heart of the pool’s circulatory system.
Without a pool pump, water will become stagnant and invite unwanted contaminants.
Since it is such an important part of a pool’s system, you should know how it works and understand the different types of pumps out in the market.
It’s equally as important to understand that pumps are not just plug-and-play pieces of equipment. Not every pump will fit your specific pool. Choosing the wrong pump can not only cost more money to operate but also damage your filters and pipes.
Whether you are a new pool owner looking for your first pump or looking for an upgrade, be comfortable in picking the right pump for your pool’s needs.
Black and Decker Variable Speed Pump
Black and Decker did not do anything spectacular with its first pool pump model. It just made a very good and reliable pump at a really attractive price point.
Pumps create a continuous flow of water and allow your water to “turn over” or completely pass through the filtration system. If your pump is off or isn’t operating at its intended levels, it can have a negative effect on both the water and equipment.
Besides the chemicals themselves, moving water is critical to fight and prevent the growth of algae and other bacteria in your pool.
How Does a Pool Pump Work?
Pumps are typically positioned before the filter, heater, or other pool equipment in your system. The pump itself can be simplified into two parts: the wet end and the dry end (motor).
The wet end, appropriately named, is the part of the pump that the water flows through. It is in a water-tight enclosure called the housing. The housing contains a strainer basket to catch any large debris before it gets into the filter and other equipment. It also contains an impeller.
The Impeller is the pulling force of the pump. It is what actually pulls the water from the pool and pushes it back in. The impeller is what connects the wet end to the motor.
The Motor is the dry end of the pump, meaning no water enters the motor. It is the driving force of the pump. It creates the speed that spins the impeller to circulate the water.
The Difference Between a Pump & Motor
You may have heard “pump” and “motor” used interchangeably when talking about pool pumps. However, there is a difference!
The pump is the whole assembly consisting of the wet and dry ends.
The motor is just the dry end.
The pump is connected by PVC pipes, often called suction and return lines. These pipes are the veins that send water to where it needs to go to be filtered or heated.
The Different Types of Pool Pumps
Pumps come in various speeds. In the past, most motors ran on one speed. While these single-speed motors are still available, they have evolved to offer multiple speeds.
These have grown in popularity due to their energy efficiency and cost savings. Most energy companies will also offer rebates and credits by switching from a single speed!
The three popular types of pumps currently out on the market are:
- Single-speed pumps
- Dual-speed pumps
- Variable speed pumps
Single-Speed Pump
A single-speed pump will only operate at one speed, rated in Revolutions Per Minute (RPMs), all of the time according to the motor’s horsepower. Single-speed pumps have been the norm for pools for decades and continue to be the choice for a lot of residential owners.
The pricing of single-speed pumps compared to their multi-speed counterparts make them seem like an attractive option. However, due to rising energy costs and the fact that you can’t change the speed, single-speed pumps are the most expensive to operate.
If you are ever looking to buy or upgrade your pump, it is highly recommended to choose a pump that offers multiple speeds.
Dual-Speed Pump
Dual-speed pumps give pool owners more flexibility in how fast the motor can run. The speeds are typically classified as low and high. High speeds are similar to a single-speed pump’s RPMs.
The low speed can sometimes cut RPMs in half, cutting energy usage and run-time costs, sometimes as high as 80%!
However, the low speed might not be fast enough to filter and circulate the water properly. Certain features like spillovers or saltwater generators might need a certain RPM level in between the high and low settings, which may force you to operate at the higher level the majority of the time.
Variable Speed Pump
Variable-speed pumps (VSPs) are the new kids on the block. They allow you to control your RPMs to whatever setting you need. Most variable-speed pumps have schedules that allow you to move water as fast or as slow as necessary.
These can handle more complex pool setups and can be automated based on your pool’s requirements.
While these pumps are more expensive upfront, they consume considerably less power and can cut your pool energy bill by up to 90%. If you do purchase a VSP, contact your energy or utility company, as most will offer credits or rebates when you install one.
New DOE Regulations on Pool Pumps
Depending on what type of pool pump you have, they can be the second-highest electrical consumer in a house after an HVAC system. Single-speed pumps in particular use a lot of energy to operate.
Because of this, the U.S. Department of Energy (DOE) announced that, as of July 2021, pumps manufactured or imported in the U.S. must meet new minimum efficiency standards. You can read a more thorough explanation of what this means here.
Overall, this is essentially phasing out single-speed pumps in favor of pumps that offer multiple speeds. This does not mean you cannot buy a single-speed pump anymore, but it might be hard to find one in the future. Some states are even introducing legislation that will prohibit the installation of new single-speed pumps.
This should sway most pool owners to think about a VSP for their next pump purchase.
Choosing the Right Pump for My Pool
There are plenty of options and features that need to be considered for a pump other than its RPMs. Choosing the wrong pump can hinder circulation and water filtration and possibly damage other equipment.
The overall goal with a pump is maximizing efficiency. How can I maintain a water chemistry balance while saving money on electricity costs?
Determine the Correct Pump Size
Finding the right pump size for your pool typically refers to the pump’s horsepower (HP). The horsepower (HP) is how forceful and quick the pump can fully circulate the pool’s water. Residential pumps usually range from 0.75 HP to 3HP. Generally, it’s better to size up because you can always reduce the RPMs (if you have a variable-speed pump).
It is generally accepted that all of your pool’s water should flow through your filtration system at least once daily. This is known as the turnover rate.
To determine what size pump is needed you need to do a little bit of math to find your pool’s flow rates, both a minimum and maximum flow rate. Essentially, how many gallons can the pump push over a period of time and how much can the filtration system handle?
The most important piece of information needed is knowing how much water is in your pool. If you are unsure, use a pool volume calculator to get a reasonable estimate.
Minimum Flow Rate
To find the minimum flow rate, divide the volume by your intended turnover rate time. For single-speed pumps, turnover is typically 6-8 hours. If you have a variable-speed pump, we can afford to move water a bit slower, about 8-12 hours. This will give you a Gallons per Hour (GPH) rate. Since most pumps calculate by minutes, we can divide the GPH by 60 to get Gallons per Minute (GPM). For example, a 25,000-gallon pool that we want to turn over in 8 hours would be:
25,000 ÷ 8 = 3,125 GPH ÷ 60 = 52.08 GPM
Your pump’s manual or specifications guide should have a section about its flow rates.
To make the GPM calculation easier, use our super-handy calculator to get a better idea!
Pool Turnover Rate Calculator
Maximum Flow Rate
The maximum flow rate is a little bit easier to find, as that is mostly determined by your filtration system: filters and plumbing (both pipe sizing and length). Your filter’s flow rate will be determined based on its size and surface area. The filter manual will have its maximum flow rate allowed.
Pipes are the other important factor when determining flow rates. You don’t want to put extra pressure on the pipes and put more water than they can handle. The pipes may have flow rates stamped on them, but if not, refer to these general numbers from Pool Parts to Go:
- 1.5″ pipes: 42 GPM
- 2.0″ pipes: 73 GPM
- 2.5″ pipes: 120 GPM
- 3.0″ pipes: 160 GPM
If your plumbing varies in size throughout its length, refer to the smallest pipe size‘s GPM.
Finally, refer to the smaller GPM flow rate between your filter and plumbing. For example, if your filter’s maximum flow rate is 96 GPM, but you have 2.0″ pipes throughout your system, use 73 GPM as your maximum flow rate.
Water Features
If your pool has a connected spa, waterfalls, spillovers, water slides, and other water features, it is highly recommended that you get a variable-speed pump.
The ability to control features with multiple flow rate requirements is very advantageous to overall circulation. You may even need multiple pumps within your system to ensure proper circulation throughout the pool.
The Right Pool Pump Makes All the Difference
Your pool’s pump is the most important aspect of your pool. Water balance and proper testing can only be achieved if the water has proper circulation.
If and when you are ready to buy a new pump, take into consideration the long-term effects of the purchase, both from an energy efficiency and cost perspective. Variable-speed pumps are more of an upfront cost, but the electrical savings each will offset that cost in just a few swim seasons. Reach out to your energy provider to learn about any rebates that they offer and know you are doing your part to reduce electrical consumption!