New Zealand's Specialist Hot Water Heat Pump Installer
Serving Wellington, Hutt Valley, Wairarapa, Kapiti, Horowhenua & Manawatu
Serving Wellington, Hutt Valley, Wairarapa, Kapiti, Horowhenua & Manawatu
Choosing between a hot water heat pump and a gas hot water system is a common dilemma for New Zealand homeowners. Gas prices have climbed sharply over the past few years, while heat pump technology has moved on too, with far better hot water heat pump efficiency than ever before.
Both have different pros and cons, but understanding their differences is sure to help you make the right decision for your home, your wallet, and the environment. Here’s how each system works, what it actually costs, and how they stack up against each other for homes across Wellington, the Hutt Valley, and Wairarapa.
A hot water heat pump doesn’t burn any gas at all. It acts a bit like a fridge running in reverse, extracting heat from the surrounding air and transferring it into your water cylinder using a refrigerant that cycles between liquid and gas. Because it’s moving heat rather than generating it directly, the process uses far less electricity than a standard cylinder.
This is where hot water heat pump efficiency really shows up. Most modern hot water heat pumps have a COP (Coefficient of Performance) of around 4.0, typically ranging from 3 to 5, meaning they produce 3 to 5 units of heat for every unit of electricity they use. A standard electric cylinder, by comparison, has a COP of just 1.0. It’s a fair claim that these systems use up to 70% less energy than gas systems, and the math backs it up. Lower emissions follow naturally, since heat pumps run on New Zealand’s largely renewable electricity grid rather than burning fossil fuel on site. And because the unit sits outside, it doesn’t take up valuable space in your home either.
Refrigerant choice matters here too. New Zealand is phasing out high-GWP (Global Warming Potential) refrigerants like R134a, which has a GWP of around 1,430. Modern systems using R290 (propane) or CO₂ (R744) have GWPs of roughly 3 and 1, respectively, and transfer heat more efficiently while having a far smaller impact on the atmosphere.
But how much is a heat pump hot water system? The initial installation cost is higher than gas, though most banks now offer a low-rate finance “green loan” to help with up-front costs. Hot water heat pumps in NZ typically cost around $7,000, including purchase and installation. That’s more than gas upfront, but the running costs claw that back quickly. And unlike some countries, being less effective in very cold regions doesn’t apply here, with modern units designed to keep working reliably down to around -10°C.
Gas has been a traditional method of heating water in NZ homes, and it still has its strengths. You get a continuous supply of hot water and never run out, even with several people showering back-to-back. Upfront installation costs are lower than that of a heat pump, and running costs are typically lower than that of a traditional resistance hot water cylinder, at least on paper.
But look past the install price, and the picture changes completely. No stored hot water means no hot water available during a power cut. Monthly line charge or bottle rental for gas can be higher than your actual gas usage charges. And burning gas or LPG produces harmful carbon emissions that a piped or bottled supply can’t avoid.
Line them up side by side, and the trade-off becomes clear. Gas water heaters vs heat pumps really comes down to the upfront cost versus long-term running cost, and the numbers below show why.
| System | Typical install cost | Annual running cost* | Emissions |
|---|---|---|---|
| Hot water heat pump | ~$7,000 | $180 – $333 | Lowest |
| Piped gas | ~$4,000 | $700 – $834+ (plus line charges) | Highest |
| Electric resistance cylinder | ~$3,000 – $4,000 | $480 – $1,176 | Moderate |
*Figures based on EECA and Consumer NZ published estimates; household usage will vary.
Gas wins on upfront cost and continuous hot water with no dependence on outside air temperature, but heat pumps win on almost everything else: running costs, emissions, and how the system pays for itself over its 15+ year lifespan. If you’re trying to cut power bills in the long term or reduce your household’s carbon footprint, the heat pump hot water system comes out ahead.
There isn’t one answer to which is the best heat pump hot water system, as it depends on your household and your site. A split system separates the outdoor heat pump from the cylinder, which can be installed inside or outside, giving you the most flexibility if space is tight or you want to keep the tank in an existing cupboard.
An integrated system combines everything into a single outdoor unit, making for a simple, all-in-one swap if you’re replacing your existing gas or electric cylinder and don’t need to keep anything indoors. If you already have a cylinder you’re happy with, it can often be retrofitted with a heat pump system rather than replaced outright.
A larger household that uses a lot of hot water will generally see a faster payback than a single-person home, simply due to higher daily use. Ultimately, you should choose a hot water heat pump for its energy efficiency, long-term environmental benefits, and impressive cost savings over time. Saving money and protecting the environment are undeniable advantages that gas hot water heating can’t match.
Most cost around $7,000, including purchase and installation, though this varies depending on household size and site conditions. When comparing costs, people typically compare the upfront hot water heat pump cost in NZ with the upfront price of gas, and while it’s higher to start, the average running cost savings close the gap within a few years.
We offer a free, “site unseen” online estimate to give you a starting figure, followed by a home visit to confirm your final written quote.
For most households, yes. The higher upfront cost is typically recovered through lower running costs within several years, and heat pumps go on to save money and reduce emissions for the rest of their 15+ year lifespan.
Yes. Modern heat pumps are designed to operate in temperatures as low as -10°C, so even a frosty Wairarapa or Wellington morning won’t stop the system extracting heat from the air. Coastal homes can also be fitted with units with anti-corrosive coatings to withstand salt spray.
No. We will remove your gas system as part of your installation.
For a hot water heat pump system that can reduce your bills by up to 70%, request a free, site-unseen online estimate from A2W. We’ll follow up with a home visit to confirm which is the best heat pump hot water system for your home and provide a written quote. There are no hidden costs or obligations; just a clear answer on what it’ll cost to make the switch.
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