Which shower pump should I choose?

This guide is designed to help you to choose the right shower pump for your property and one that’s best suited to your needs and expectations.

Choosing the right shower pump can seem like a daunting task because there are several factors to consider: negative or positive head, twin or single, brass or plastic, 1.5 or 2.0 or 4.0 bar. Let’s simplify these and find out how a shower pump works so you can find out which option is best for you.

How does a shower pump work?

A shower pump pumps your low-pressure water through a quickly-spinning impeller which, using centrifugal force, pumps the water out at a higher pressure.

Should I choose a positive or negative head shower pump? 

Well the first basic difference between shower pumps is whether they are positive head or negative head pumps. A positive head pump works off of flow, whereas a negative head pump works off of pressure. Which option you choose generally depends on the location of your water tank. 

A positive shower pump relies on gravity to feed the water from your tank into the pump. This flow starts the impellers which pump the water to your shower. It’s recommended that your water tank should be approx 1m above your shower head so the water will have enough speed to get the pump working.

If you want to pump a system where the tank is above the pump, you generally need a positive head pump. 

But if you have a situation where the outlet (i.e. your tap or shower) is above the tank, then you need a negative head pump. 

This is because a negative head pump (also known as universal) doesn’t rely on gravity. Instead, a negative shower pump pressurises everything in the pipe to ensure that the pump starts each time, even when the flow rate is low.

If your shower head is at the same level or higher than your cold water storage tank, you likely need a negative head pump.

Which is best – 1.5, 2.0, 4.5 bar?

These numbers indicate the pressure at which the pump operates against a closed head. For example, 1.0 bar shower pumps are best suited to small shower heads. 1.5 and 2.0 bar shower pumps are best for low pressure situations where your shower needs a boost in pressure. Higher pressure pumps are for larger shower heads and power showers.

Do I need a single impeller pump or twin impeller pump?

A single impeller shower pump can only pump one type of water, either hot or cold, whereas a twin impeller can pump both hot and cold water equally. Usually, you will have a hot and cold supply, both in and out, so twin impeller shower pumps are the more common type of pump found in most homes. Single impeller pumps tend to be used when you have an issue with the pressure of one or other of your water types.