Heat pump hot water cylinders in Christchurch

How heat pump hot water works

An ordinary electric cylinder heats water with an element, the same way a jug does. A heat pump water heater works like the heat pump on your wall in reverse: it draws warmth out of the outside air and moves it into the water. Moving heat takes far less power than making it, so the same tank of hot water costs much less to heat. EECA, the government's energy efficiency agency, puts it at around 60–75% less electricity than a conventional electric hot water system.

• Lower power bills. Water heating is one of the biggest parts of a household power bill, and this is where a heat pump saves.
• Mains pressure hot water. Heat pump systems run at mains pressure, so showers are a lot better than on an old low pressure cylinder.
• Electric only. No gas supply or bottles needed, and it pairs well with solar panels or a cheaper night rate.

Integrated or split?

Integrated (all-in-one)

The heat pump sits on top of the cylinder as one unit, installed outside. Simple, tidy, and it frees up the cupboard inside where the old cylinder was.

Split system

A small outdoor heat pump unit connected to a cylinder that can stay inside, often in the same cupboard as the old one. It suits houses where there isn't room outside for a full cylinder, or where the cylinder needs to stay close to the bathroom.

Brands we install

We supply and install heat pump hot water from Rheem, Haier, Ecospring and Rinnai. They differ in capacity, how well they cope with cold mornings, how quiet they are and how they're controlled, so we recommend the one that suits your household and your site rather than whatever is easiest to get. You're welcome to buy your own unit too, as long as it's suited to the site.

What we look at first

1. Where it goes. The heat pump needs airflow and room around it, and it makes a gentle hum when it runs, a bit like a fridge. We place it away from bedroom windows and a neighbour's fence where we can.
2. Christchurch frosts. Heat pumps work harder as the outside temperature drops. We pick a unit rated for our winters and size it so you still have plenty of hot water on a frosty June morning.
3. How much hot water you use. Cylinder size comes down to the number of people, showers and baths, not the size of the house.
4. The pipework and pressure. Coming off a low pressure cylinder, the existing pipes need to be fit for mains pressure. Old or undersized pipe gets sorted as part of the job, and we tell you before we start.
5. The electrical supply. The unit needs its own power supply. If the existing one isn't suitable, that's an electrician's job, and we'll tell you at the quote stage.

Then it's in: the old cylinder disconnected and taken out, the new system installed on a proper base and restrained, new valves and a tempering valve so the hot water at your taps is at a safe temperature, condensate run away, and the whole thing tested and commissioned.

Is it worth it?

For most Christchurch households with a working electric cylinder that's due for replacement, a heat pump is the lowest running-cost way to heat water. The honest trade-offs:

• Higher upfront cost than a standard electric cylinder. The savings come back on the power bill over the life of the unit.
• It needs the right spot outside, with airflow and not right under a bedroom window.
• Efficiency drops in the cold, which Christchurch has. A unit sized and rated for it handles this fine; an undersized one doesn't.

If gas or a standard mains pressure cylinder suits your place better, we'll say so. The options are compared on our hot water cylinder page and our gas hot water page.

Repairs and servicing

Already have a heat pump water heater? We service and repair them: water not hot enough, error codes, the unit running constantly, leaks from the valves or tank, and noise that wasn't there before. Where a repair isn't worth it on an older unit, we'll tell you straight and quote the replacement instead.

What it costs

The price depends on the unit, the size, integrated or split, and what the existing pipework and power supply need. We look at the site and give you a fixed quote, free in Christchurch. Our pricing is affordable and competitive, and what we quote is what you pay. Repairs are charged at our published hourly rates.