Roberts says he has always been conscious of where the money is going at home and, after looking through his energy bills, he found he was spending around $1,000 a year on gas, with prices expected to keep rising given the issues around supply.

After hearing about the hot water heat pump group discount scheme, which offered a good chunk off the upfront cost, he registered his interest and had his Emerald model installed recently by Morgan Ford and the Laser Electrical Queenstown team.

Like many other electric machines, hot water heat pumps are a bit more expensive upfront but are far more efficient and therefore much cheaper to run than traditional electric hot water cylinders or gas systems.

As Ford says, while they are still relatively uncommon in the region, they are becoming more popular - especially in new builds and retrofits - and word is spreading about how good they are. They work particularly well for those with solar as the water can be heated during the day with the cheapest electricity available.

There are big benefits if we can shift away from peak use. Ripple control has traditionally been used to reduce strain on the grid and avoid using electricity for hot water, but it's a blunt instrument. Those on time-of-use plans can now set their system through an app (or use simple timers) to heat at certain off-peak times and save.

Batteries are great, but if you're not ready to make that investment just yet, Ford says the cylinder can also act as a 'thermal battery' and make the most of that cheap energy to get the water ready for the morning and night rushes.

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