Our First Install: A Melbourne Family Took Their Gas Boiler Off the Wall. Here's What Happened.
For five years, Mike and Kay wanted to get off gas.
They have a hydronic home in Hawthorn, radiators, the kind of even, quiet warmth that gas hydronic does well and that most heat pump retrofits struggle to match. They knew the gas boiler's days were numbered. They'd watched the bills climb. They'd looked at the alternatives more than once.
And every time, the same wall: a traditional hydronic heat pump replacement in Australia runs $20,000 to $40,000. For a like-for-like comfort upgrade, that's a hard number to justify.
In their own words, the week we took the gas meter off the wall:
"We've been looking for 5 years for a hydronic heat pump, but we didn't want to pay $25,000. We finally did it."
Mike & Kay, Hawthorn
In early May, their gas boiler came off the wall. The gas meter came off the house entirely. And they became the first Australian home to run a gas hydronic system converted to a Thermal Dawn heat pump with thermal storage.
This is what's happened since.
What we actually installed
We replaced the gas boiler with a Thermal Dawn system: a reverse-cycle hydronic heat pump paired with a 35 kWh thermal store: an Australian-made, heavily insulated tank that holds heat as hot water until the house needs it.
The radiators stayed. The pipework stayed. That's the point. We didn't rip the house apart to switch fuel. (If you're wondering whether your own radiators are compatible with a heat pump, that's the single most common question we get, and we wrote a full explainer on flow temperatures and radiator compatibility.)
The behaviour change is the interesting part. A gas boiler burns fuel the moment you want heat. Thermal Dawn does it on a different clock:
- It charges the thermal store during the day, when Mike and Kay's rooftop solar is generating, plus a 3-hour free-electricity window their retailer offers.
- Then it heats the house off stored energy through the evening and overnight: the peak hours when grid power is most expensive.
As Mike put it, watching his own dashboard: the grid barely sees it.
The numbers, from the customer's own app
These aren't our numbers. They're the running totals off Mike and Kay's own Thermal Dawn app, from the day the system went live in May: live
| Since going live | Result |
|---|---|
| Money saved | $1,190 |
| Gas avoided | 24,199 MJ |
| CO₂ avoided | 1,241 kg |
Hold those at arm's length for a second, so let's be clear about what they are: readings from a system that's still being tuned. We have a follow-up visit booked to add bypass valves and tighten the zoning, which should cut consumption further. So treat these as a floor, not a finished result.
But even as a floor, the trajectory is hard to ignore: over a thousand dollars and more than a tonne of CO₂ in the first winter months, from one home, swapping one gas load for stored solar. Sustained across a full year, that pace sits well inside the savings range we model for a home like theirs.
The moment that surprised us
We brought in a licensed plumbing partner, Hub-Air, to run the install with us. One of the installers on site, Dale, had spent his career on gas. He was, politely, a sceptic about heat pumps for hydronic.
By the end of the day he'd asked to do the next job.
That mattered more to us than the bill savings, because it points at something bigger than one house. The reason gas installers stay off heat pumps isn't loyalty to gas, it's that heat pump hydronic has historically been fiddly to spec and size. We pre-configure the system so the technical risk is taken out before anyone arrives on site. Take that barrier away and even a gas lifer wants in.
What this changes for us, and for you
We built Thermal Dawn's demand before we had a product to point at. No case study, no install photos, no proof. People put down deposits on the strength of the idea.
That's now over. The first install is done. The second is now in and running, and more are in the build queue.
If you've been waiting for someone else to go first, someone else's roof, someone else's radiators, someone else's bill, that home now exists, and it's in Melbourne.
A few plain notes before you read on:
- These are figures from one home. Your results depend on your home, your solar, your climate zone, and how you heat now. A site assessment is how we give you a real number, not a brochure number.
- We're past the "spaces limited to 100" stage of our own marketing. There are a fixed number of early-install spots open behind the ten already in build, and they come with our best pricing and an extended warranty, because being early shouldn't mean carrying the risk.
Want to be one of the next ten?
Two ways in, depending on where you're at.
Ready to talk about your home? Request a quote and book a free site assessment. We'll confirm whether Thermal Dawn fits, and give you a fixed quote, no obligation until you approve it. If you want to lock your place in the queue, the reservation is a fully refundable $190 deposit.
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