Turning the heat down – the Hot Water Sorter

The Hot Water Sorter is an initiative which is potentially good for both customer’s bills and everyone that calls New Zealand home.

In a nutshell, the programme sees power to customer’s hot water cylinders being turned off for a short period at certain times of the day. Hot water cylinders retain heat really well, so they don’t actually need to be going 24/7 to still have hot water when it’s needed.

When we’re all using power at the same ‘peak’ times (like first thing in the morning and again in the early evening), New Zealand often has to draw on electricity generated from non-renewable sources like coal, gas and diesel to meet demand.

If more power usage can be shifted to off-peak times or less used during the peaks, we could reduce our reliance on non-renewable energy generation.

Frequently asked questions

We launched the programme in late April 2024 with a few regions in the North Island and will continue to add to these regions throughout the year. 

We’ll let customers in each area know when it’s available but our goal is to make the Hot Water Sorter ready for as many customers as possible over the next few years - the more, the merrier.

In short, there are two ‘peaks’ in demand for electricity during the day; in the mornings when most people are getting up and showering, brewing their morning coffee, then again in the early evening when the lights and heat pump get turned on, dinner is cooking and the kids are being bathed.

Typical peak usage times across homes in New Zealand homes

Power usage peaks

Note – this diagram is for illustrative purposes only

If more power usage can be shifted to off-peak times or less used during the peaks, like not heating our hot water cylinders when we don’t need to, we can help to reduce reliance on non-renewable electricity generation, which is good for everyone who calls New Zealand home.

In 2023, we ran a small three-month trial in Manawatu, Taranaki and Wanganui to check if managing customers’ hot water was a good idea. The vast majority of these customers said they’d be on board for a permanent hot water control programme which gave us the reassurance we needed to make it a more permanent thing. 

Great question! We use special software to seamlessly connect your meter to the 4G network to turn your hot water off and on again. We’ll do this at a peak time that is right for your household so it shouldn’t have any impact on your hot water needs.
In some areas yes, it is, but it is only very occasionally turned off by the local network company. We will be doing it more often to hopefully save customers a little bit of money and reduce reliance on fossil fuels.

We already have a suite of Good Plans that give customers periods of free or discounted power during off-peak hours. This means the more they shift, the more they are set to save. These plans are proving very popular! Customers love having control and power (excuse the pun) over what they can do to help themselves at home.

We're also big fans of electric vehicles, solar panels, and batteries, and we're super excited to bring you even more nifty products in the future.

If you've received an email about our hot water initiative, this is for you:

Simply complete our form to let us know together with your account number – you’ll find this on your bill email.  We’ll take care of the rest. If you want to join later on, no problem. Please email us.

It’s very unlikely that you’ll run out of hot water as most hot water cylinders are pretty large and will still have power running to it for the majority of the time. During our 2023 trial only those with very small hot water cylinders ran out of hot water (which they were already experiencing beforehand).

Just like your kettle in the kitchen, your cylinder uses an element to heat the water to a certain temperature. As the water in the cylinder is used, it is designed to automatically fill back up and start heating again, even if you’ve only used 20% of what’s in there. Once it’s heated up, your hot water cylinder retains that heat really well.

When your cylinder gets turned off at certain hours, you can still use the water that’s already toasty in the cylinder. However, if all the family or flat mates decide to shower while we do this, there’s a very small chance it may run out.

If you find you’ve run out of hot water after using a lot of it, please wait a couple of hours from when you notice to allow your cylinder to reheat. You should find you have hot water again after that time. However if you don’t, please email us and we’ll get back to you quickly with next steps.

To get hold of us urgently, call us on 0800 22 44 24.

Everything will happen for you behind the scenes, there is nothing you need to do.

We can’t guarantee you will save money because there are other factors at play. For example, your energy usage may go up in other ways - like if you have more people staying in your house using more power than usual or a spell of cold weather means you use your heaters more often. Another scenario is that you’re simply not using a lot of energy at the time we turn your cylinder off.

However, we hope you will see some very small savings on your bill because you aren't keeping the water hot when you don't need to.