Variable Speed Pumps - Pros and Cons
If you are considering replacing your single speed pump with a Variable Speed Pump (VSP), you may be wondering if it’s a good idea. There is a ton of information on the web that can be overwhelming and confusing. Here we are going to take a simple look of the pros and cons of variable speed pumps.
Pro: They Are Energy Efficient
Single speed pumps use windings only. They tend to lose a lot of energy from the motor. If you have ever touched your single speed pump motor, what does it feel like? Hot, right? With a variable speed pump it will utilize windings in conjunction with a permanent magnet motor. They are totally enclosed and fan cooled (TEFC) this preventing heat (energy) loss.
VSPs are capable of using less energy than a standard, constant-flow pump. The pump will operate at slower speeds when it needs to and speed up when necessary, so you don't have a pump that is always running at its highest functional capacity level and will not consume as much energy.
One perk of variable speed water pumps is the fact that you can set them to automatically adjust flow rates if you are not going to be around to make adjustments yourself. For example, say you want higher speeds during the day for your water well, but do not need such high-speed water pumping action at night. You can set the pump to automatically operate at a lower speed at a certain time of day.
Con: They Need to Be Programed
Your single speed pump was simple: on at 3,400 RPMs (revolutions per minute) or off. Since variable speed pumps do just that, run at varying speeds, they have to be programmed. With multiple settings at literally any speed option, it can be confusing to know what speed to run and how long to run it. They keypad has a lot of buttons and many customers find it complicated to program their variable speed pumps, even if they know their desired speeds.
Pro: They Are Quieter
A single speed pump runs at 65-90 decibels from about 2 feet away. This can be as loud as riding a subway car. An energy efficient pump compares at 30-45 decibels. You know what else falls into that category? Moderate rainfall.
Con: They Require More Relays and Only Communicate with Like Products
If you swimming pool system is automated, or you are considering ever going to automation, variable speed pumps need to be able to communicate with your automation system, This may limit the brand you choose. Also, where single speed pumps require only a single relay, variable speed pumps require multiple to function correctly.
Con: They Are Expensive
A lot of people shy away from variable speed pumps simply because of the cost. That is primarily because they either cannot see the value, or are shopping in the wrong place.
Naturally, a water pump that has adjustable speed capabilities are going to be costlier to invest in than a pump that only operates at one speed. These pumps have an extra relay in the motor that allows it to be slowed down and sped up as needed. For most people buying these pumps, the extra cost is worth it because they make their money back in energy savings over the long run.
Con: They Are Larger
Variable speed pool pumps are longer than some single speed pumps. Your installer may have to re-plumb all of your equipment or knock down walls to accommodate a new VSP.
Con: Variable speed units may not have as long of a life span as a standard pump.
Since the motor in a variable speed pump is going to be consistently switching to different speeds, it can mean a little more wear on the motor and a little shorter life span than a standard pump. Some units do still offer generous warranties and guarantees of service for several years. As long as you are picking a top-of-the-line model, you should still get a lot of years of use out of your pump.
Pro: They Save You Money
We have already touched on energy savings. Energy savings convert to less money on your electric bill. Because we are running our pump on a lower RPM, we are using less energy and keeping our costs down. Even if you were to run your variable speed pump at 3,450 RPMs like your single speed runs, it would still be more efficient.
Given that there are a lot of factors to consider when determining if a VSP is right for you, it can be helpful to have a trained technician asses your individual needs. Often times, that pros can greatly outweigh the cons.