What is a hot water heat pump?

Before we tell you all about hot water heat pumps, whether or not to get one, and how to pick the right one, let’s go right back to basics. What is a hot water heat pump?

This article is part of our series on hot water heat pumps. See all the other articles here.

Your hot water system

Hot water heat pumps are just another type of hot water system that supplies all that nice hot water that you use to shower.

At home, you might have a hot water cylinder like this:

A typical electric storage hot water system.

This is a type of storage hot water system, where water is heated using gas or electricity (or solar energy) and is kept hot, ready for use.

Or, you might have an instantaneous hot water system like this:

Instantaneous hot water systems heat water at the moment you need it, which means you theoretically will never run out of hot water.

Why hot water heat pumps are different

Hot water heat pumps are a type of storage hot water system that heats water and stores it in a tank.

Instead of generating heat, hot water heat pumps move heat from the air into your water. It works exactly like a fridge but in reverse. 

Even if the ambient temperature doesn’t feel very warm, there’s still a lot of heat energy in it. A heat pump can take all that energy and heat a tank of water to 60 degrees C – the same temperature as traditional hot water heaters. 

Because it takes so much less energy to move heat instead of generating heat, hot water heat pumps are about 4x more efficient than traditional electric or gas water heaters. 

How much could you save with a hot water heat pump?

Hot water heat pumps (along with solar heat pumps) are simply the most efficient and climate friendly way to heat water at home.

Higher efficiency means less electricity or gas used, which means lower bills. The amount you save depends on what type of hot water heater you’re switching from and how much water you use.

To give you an idea, a 4-person household switching from a traditional electric hot water heater would save $685 a year in electricity bills and 20 tons of CO2 emissions over the next 15 years. 

If you get home solar you could save even more since you can time your hot water heat pump to run during the day, when your solar panels are generating the most electricity.

What are the downsides to hot water heat pumps?

There are really only three main potential downsides.


Some models of heat pumps can be noisy, particularly the more affordable ones. This means that you probably don’t want them near your bedroom or in areas where you want some peace and quiet. 

That being said, they’re not that noisy. The noise levels of the most popular models in Australia go from 49dB (slightly higher than a refrigerator humming) down to 37dB (about as loud as a whisper). 


If you have an instantaneous hot water system, then installing a hot water cylinder will take up more space than you’re using right now.


The upfront cost of a hot water heat pump can be higher than a traditional hot water heater.

Your bills will be lower, but depending on what model you get and what hot water system you’re upgrading from, the cost of upgrading may or may not be worth it. However, government rebates help with this.

Government rebates 

Heat pumps have so many benefits for energy efficiency and combating climate change – which is why both the federal government and state governments offer rebates if you install or upgrade to a hot water heat pump. 

The exact amount of the rebate depends on the size of the system installed and where you live, but will generally be from a few hundred dollars up to a few thousand dollars.

In some cases you might be able to get a new system installed for only $33, although there are questions about the quality of such cheap systems so we recommend you choose a brand that may cost a bit more, but will have better performance in the long term.

Next steps

You might have heard some good (or bad) things about hot water heat pumps already. Read more about some of the controversy.

Or if you want to know whether a hot water heat pump is worth it for your house, get an instant cost, savings and rebates estimate.