What Is A Heat Pump
Heat Pump
3 minutes
19 Sept 2025
Written by Jake Deppeler — Plumber & Founder of Trust Trade
What Is a Hot Water Heat Pump?
This blog is written by a plumber, for homeowners who just want a straight answer. If you’re replacing your hot water system and keep hearing about heat pumps, here’s what you need to know explained simply.
A Plumber’s Explanation of How It Works
A hot water heat pump is basically like having an air conditioner that runs in reverse, but instead of cooling your house, it heats your water.
Here’s what happens:
It Pulls Heat Out of the Air
Even on cold mornings, there’s heat energy in the air. The heat pump’s fan pulls that air in and passes it over a special liquid called refrigerant.The Refrigerant Absorbs the Heat
The refrigerant is designed to “pick up” heat very easily, even from cool air. As it absorbs heat, it turns into a warm gas.The Compressor Heats the Gas
The gas is pushed through a compressor. When you compress gas, it gets very hot — that’s where most of the heat comes from.The Hot Refrigerant Heats the Water
That hot refrigerant flows through pipes that wrap around (or sometimes run inside) your water tank. The heat moves from the refrigerant into the water until your tank is full of hot water.The Refrigerant Cools and Repeats
Once it’s given up its heat, the refrigerant cools down, turns back into a liquid, and the whole cycle starts again.
This process uses electricity only to run the fan and the compressor not to directly heat the water. That’s why a heat pump can heat your water while using far less power than an electric element or gas burner.
Why Homeowners Are Choosing Heat Pumps
Cheaper to Run – Many households save 50–70% on water heating bills.
Works in Cold Weather – Good models still pull enough heat from the air to work in winter.
Better for the Environment – Lower energy use means lower emissions.
Rebates Available – In Victoria and many other states, you can get thousands off the purchase price through government programs.
What You Need to Know Before Switching
They Cost More Upfront – But the savings on running costs usually make up for it.
They Need Airflow – They work best outdoors or in a well-ventilated space.
They Make a Low Hum – Similar to an air conditioner running outside.
Install Matters – A good plumber will size the system right for your household and install it where it will work at its best.
The Bottom Line
A hot water heat pump is a smart, energy-efficient upgrade. You’ll pay more to buy it, but you’ll save on bills every month, and it’s better for the environment.
As a plumber, I see more and more households switching to heat pumps because they just make sense — especially with today’s rebates and rising power costs.
If you’re ready to make the switch, use Trust Trade to connect with verified local plumbers who can install it properly so you get the most out of your investment.