Perth weather and a heat pump
Winter nights around 8°C
The mean July minimum is 8.1°C at both of the Bureau of Meteorology's Perth stations we checked, Perth Airport and Perth Metro.
Freezing mornings are rare
Perth Airport, with records from 1944 to 2026, averages 2.5 days a year at 2°C or below and 0.2 at 0°C or below. Perth Metro, from 1994, averages 3.2 and 0.1.
The unit sits out in summer, too
Perth Airport averages 28.8 days a year at 35°C or hotter and 4.6 at 40°C or hotter. Ask where the outdoor unit can sit with shade and air around it.
Leaving gas behind
ATCO Gas Australia owns the gas networks across greater Perth. If the heat pump replaces gas hot water, a licensed gas fitter deals with the old supply and gives you a Notice of Completion.
STCs: the discount we found for WA
We haven't found a WA rebate for heat pumps. What applies in Perth is the national small-scale technology certificate scheme: an air source heat pump under 425 L can create STCs, as long as the model is on the register.
Owners often hand the certificates to an agent in exchange for a discount or a delayed cash payment, so the figure on your quote may already include them. The installer must also meet WA's licensing requirements, and certificates are issued until the scheme ends in 2030. More on our STCs page.
The install, under WA rules
A heat pump is a water heater, so installing one is major work in WA. The plumbing contractor lodges a notice of intention at least 24 hours before starting and must give you a certificate of compliance within five working days of finishing.
When a water heater is replaced or relocated, WA requires a temperature control device, except on basins. That keeps showers and other bathroom fixtures used for personal hygiene at no more than 50°C.
A restricted plumbing permit only covers a replacement where no pipes change, so if pipework is moving, check the installer holds a plumbing contractor's licence. The licence or permit number should be on your quote.
Before you book an install
- Photograph your current system's label, including its size.
- Pick a few outdoor spots with open air around them, away from bedroom windows.
- Check the model you're offered is on the STC register.
- On gas now? Ask who will cap the gas line, and when you'll get the Notice of Completion.
- Ask how the tempering valve is handled, and whether it's in the quote.
What we would do
Plan a heat pump while your current system still works, so the choice isn't made on a cold shower morning. Ask for one written quote that names the model, shows the STC discount and includes the tempering valve and any gas capping. Then check that a certificate of compliance arrives within five working days of the install. For the noise and placement questions, read our page on heat pump noise and problems first, then let us match you with a plumber who specialises in heat pumps.