Electric hot water cylinders
Electric hot water cylinders are the most common form of water heating in New Zealand.
- Relatively low upfront cost.
- Some have smart controllers which vary when and/or to what temperature the hot water is being re-heated according to your household’s needs. By not keeping the cylinder constantly full of hot water when it’s not needed, these controllers are primarily designed to reduce a cylinder’s heat loss through its insulated walls. With a conventional modern electric cylinder, this heat loss costs about $90 to $150 per year. A smart controller can cut a portion off of this – by how much depends primarily on how much “spare capacity” your cylinder has, and the effectiveness of the smart controller.
- You can buy cylinders with additional connections suitable for having a solar water heater, heat pump water heater or wetback added in the future.
- Can be put on a controlled or night-rate electricity supply to get a lower electricity price.
- A night rate electricity tariff in particular could lower your hot water bill substantially. It's not available in all areas of the country though - check with your electricity supplier first. Before switching to night rate, test that your cylinder is big enough to store a day's water. Switch it off first thing in the morning and back on before you go to bed for a couple of days to see if you run out of hot water. If you have enough hot water to see you through, organise a night rate tariff with your electricity supplier. For those with insufficient hot water, some electricity providers offer a night rate tariff with an additional hot water boost during the day. Check with your provider to see if they offer this service.
Keep in mind
- The running costs of electric hot water cylinders are relatively expensive compared to other water heating options (unless a cheaper night rate tariff is used).
- To reduce heat loss, put a hot water cylinder wrap around the cylinder, and pipe insulation around the first metre of the hot water pipe, particularly if you have an older hot water cylinder installed pre-2002. They are available from hardware stores.
- The system needs to be correctly set up to ensure the water in the tank is regularly heated to 60oC to prevent the growth of legionella bacteria.
- Use our water heating systems tool to compare the upfront and ongoing costs of different water heating options for your situation.