Your trusted heat pump hot water experts

For heat pump hot water to be more attractive than gas hot water, we need the units to last. We're not making any financial or carbon savings if we need to replace the units every 5 years. The good news is that there are affordable units on the market that should last 10 to 15 years. Unfortunately most manufacturers warrant the units for only 5 years, but I will keep putting pressure on them to increase these warranties. Some premium units come with a 15 year warranty on the tank and are split systems, meaning if something breaks, you can replace part of the system rather than throw the whole thing out.

I've seen heat pumps from as low as free, to as high as $7,000. I divide the market into three categories:
• Cheap and (hopefully!) cheerful - you can often see units on Facebook marketed for less than $1,000. Buyer beware.
• ⁠Mid-market - units from the low $1,000s to around the $4,000 mark. There are some good quality units in here, but some rubbish as well.
• ⁠Premium units - there are a few units on the market which fetch above $4,000. These are quality units, but buyers should still be discerning.

There are two options when to switch to heat pump hot water. The first is when your current unit dies. Every time a hot water service dies is a perfect opportunity to replace it with a more efficient option. It will also seem less expensive - you'll need to pay for a new appliance one way or the other, so the cost is only the difference.

The other option is before your unit dies. This might be a good idea where you use a lot of hot water, you're eligible for rebates and your expected savings from switching are significant. People with solar stand to save even more as they can effectively run their units for free.

Your first piece of homework is How to choose a heat pump hot water unit", where I set up a framework to help you understand the key features of units. Once you've read that, then head over to our reviews of units to see how we compare units.

There are a few points to consider here:


1. Heat pump hot water units tend to be larger than gas storage units. Gas storage units can be run at any time, the cost of gas doesn't change during the day, so it doesn't matter whether water is being heated during the day or night. Heat pumps on the other hand should be run during the day, for two main reasons. First, they work by sucking heat out of the air and pumping it into the water. There's more heat in the air during the day so they'll operate more efficiently. Second, if you have solar, run them during the day and it will effectively be free. So think about running heat pump hot water for one cycle per day, rather than heating continuously.
2. The general rule of thumb is 50L of hot water per person per day.
3. We also want to allow for the number of bedrooms, if the number of occupants in the house is likely to change, as well as guests.
4. Baths and teenage daughters - also consider whether you have any large uses/users of hot water. My daughters are still young, but I've heard once they hit their teens their water usage can increase exponentially!

There are a range of rebates that make heat pump hot water more affordable. Please see my article for more information.

Nothing's perfect and heat pump hot water units have a few negatives which you should be aware of. They are big units and they need to be installed outside, so you'll need the space. They are also noisier than gas units (but this isn't usually an issue as we recommend units are run during the day). They can cost a lot, with some premium units costing upwards of $7,000. But there are also more affordable units, many cheaper than gas equivalents.