Single Speed, Two Speed, and Variable Speed Pool Pumps: Which is Best?

The pool pump is the heart of your swimming pool. It is the single piece of pool equipment most responsible for keeping your pool clean. The pump maintains the circulation of the pool, making sure that all of the pool’s water is passed through your filter regularly. But it is also the most expensive piece of equipment to keep running. A pool pump often uses more electricity than any other appliance in your home. Some modern pool pumps are much more efficient and save on energy consumption, but they are more expensive to install. So when it comes to the three types of pumps, single speed, two speed, and variable speed pool pumps: Which is best?

Single Speed, Two Speed, and Variable Speed Pool Pumps [infographic]

A Few Facts

The original style of pool pump is a simple, single-speed pump. You turn it on, and it starts to work, and the rate it pumps never changes. It is either on or off. But running that kind of pump is expensive. Here are a few facts:

  • A single speed pool pump can account for 25% of your energy bill.
  • It uses more energy than any other single appliance in the house.
  • A single speed pool pump can use three times as much electricity as a typical refrigerator.

Of course, not all pool pumps today are such voracious energy consumers. Today, modern pumps can use anywhere from 40% up to 90% less electricity than a single speed pump. The three types of pumps today are:

  • Single Speed – Either on or off, generally high powered
  • Double Speed – Can be set to full speed or half speed
  • Variable Speed – Dial or digital display can precisely set any speed between full speed and off.

Single Speed Pool Pump

A single speed pool pump is the tried-and-true, classic pool pump. It has been around for decades and has proven to be effective and reliable. Because it is a relatively simple pump, it is also the cheapest. Purchase costs can range from $250 to $500 or more for specialty and extra-large pumps. The pumps are usually rated by horsepower. Less powerful pumps, suitable for smaller pools, can use as little ¾ horsepower. Larger residential pools may use pumps in the 3-5 horsepower range. Commercial pools that are much larger than residential pools and see more regular heavy use can use pumps of up to 20 horsepower.

The amount of horsepower is the most significant factor in how much energy a single-speed pump consumes. More horsepower requires more energy. However, even a residential pump can use three times as much energy as a refrigerator. It is exceeded only by heating and air conditioning as largest the consumer of electricity in the home. Because it only runs one speed, it does not have the energy savings option of a two-speed or variable-speed pump. Often, single speed pumps are too large for their pools and unnecessarily waste electricity.

Two Speed Pool Pump

A two-speed pool pump is a step up in functionality from a single speed pool pump. It works in the same fashion, but it has two settings, a full speed option and a half speed option. The half speed option provides higher efficiency, saving on energy consumption and electricity bills. It is not only a greener option, but it is also more cost-efficient. The trick to a two-speed pool pump is the rule of slow and steady pool water circulation. By circulating the water more slowly, friction is reduced, creating significant energy savings. Less power is required to move the water.

When engineers describe the function of pumps, they use the Affinity Laws. Without getting too technical, these laws describe how reducing the speed of a pump actually creates disproportionate savings in energy. Basically, when you reduce the RPM of your pool pump by 50%, you get more than a 50% saving in energy. Instead, reducing the RPM by 50% creates an energy saving of 75%. If you reduce the RPM by 66%, you get an 89% reduction in energy consumption. So by using the half speed option, you can save 50% to 75% in energy costs.

Another advantage of the half speed option on two-speed pumps is that it cleans the water better. Instead of running the pump at full speed for a shorter period of time, most homeowners run a two-speed pump at half speed 24/7. The water moves more slowly through the filter, giving better filtration. Also, the pump is much quieter at half speed. The only time to use full speed is when you are using a water heater, which requires a high water flow, or when you are vacuuming the pool.

Variable Speed Pool Pump

A variable speed pool pump is the Cadillac of pool pumps. It is the most expensive pump to purchase up front, but the energy savings typically pay off the initial cost in one to two years. Once the initial cost is recovered, the savings can be dramatic. A variable speed pump can easily reduce energy consumption by 90% compared to a single speed pump. That means much lower electricity bills. Plus, it’s good for the environment!

What makes a variable speed pump so special? The name says it all. A variable speed pump can be fine-tuned to the exact RPM you need to keep your water moving at a healthy speed. As we noted with two-speed pumps, slower is better, and a variable speed pump lets you get exactly as slow as will work for your pool. In addition, variable speed pumps use a more efficient engine. Single and two-speed pumps use induction motors, which are relatively inefficient. Variable speed pumps use a permanent magnet motor, the same kind of motor you’ll find in an electric vehicle. It is much more efficient and creates much less noise, heat, and vibration. Because they run cooler and vibrate less, the internal components of a variable speed pump can last much longer than other pumps, adding to the long-term savings.

Variable speed pumps typically have digital controls and advanced diagnostic systems. If there is a problem with the pump, the diagnostics can make it quicker and cheaper to find the problem and repair it. The extreme energy efficiency means that running a variable speed pump can cost as little as $10 a month, compared to $50 for single speed or $30 for a two speed.

Which Type of Pool Pump Should I Get?

When it comes down to it, the type of pool pump you get will be determined by your ability or willingness to spend upfront for long-term savings. The amount of savings and payoff time for different pumps also depends on factors like how much you use your pool and how much electricity costs in your location. In places with high electricity costs, the payoff time on more expensive pool pumps will be shorter. If you use your pool for a more extended season or all year round, you will also have a shorter pay off period. In places with low energy costs and short swimming seasons, the savings will be less dramatic and it will take longer to make up the added cost of more expensive pumps.

In a climate where pools are mostly used in the warmer months, like here in Georgia, the payoff time for a two-speed pump averages about 12 months. For a variable speed pump, it may take 24 months to accumulate savings equal to the extra cost of the pool pump. However, once you have made up the difference in price, the savings continue and can be dramatic. So if you can afford it, installing a more expensive pump will definitely save you money in the long run.

The Pool Butler can help you install any kind of pump, or replace your existing pump. We are also available for cleanings, repairs, and consultations. If you have questions about which pool pump is best for you, just contact us, and we’ll be happy to help!

The Pool Butler