Thermal Dawn's thermal battery replaces gas boilers with cheap stored heat and cooling

Another great idea from Down Under: Thermal Dawn promises cost effective heating and cooling, mainly by replacing gas boilers in cold climates. CleanTechnica had a chance to interview Nick Zeniou, Founder of Thermal Dawn, recently by phone, fresh after his presentation at Everything Electric. You can hear him explain his revolutionary system here, or here with a little less drama.

Everything Electric was a good opportunity to measure public reaction to the new product. Nick tells me that hundreds of people checked out their stall. “People care about carbon cost and comfort. People don’t compromise on comfort.” Sounds like comfort trumps carbon cost. Homeowners who visited the stand and filled out the survey were focused on sustainability and cost. Nick cautions: “it was an electrification expo crowd, and 50 of the 62 already had solar, so it’s not the whole market.” See the chart below.

Although I live in the warmer part of Australia (Brisbane), many Aussies have to endure cold winters. Nick tells me he is looking at installs in Sydney, Canberra, and Melbourne in the deep south. Thermal Dawn can store heat up to 70 degrees Celsius, or down to 5 degrees. Thermal Dawns’ equipment can run cold or hot water through pipes and radiators that are already installed, depending on the need — without having to run an expensive gas boiler. He describes it as a thermal battery. Just to be clear, it does not generate electricity.

Check out this graph below, which shows the Thermal Dawn system in action at a house in Melbourne during a day in August 2026. It shows room temperature and when the heat pump was running, in 15-minute samples, unedited. The heat pump ran until about 1:45pm, then not again, heated by stored energy through the evening peak.

“What about return on investment,” I asked. He described two systems they have had running over the southern Australian winter which have saved the homeowners approximately AU$1,500 each. “The first was a house in Melbourne, our first install, live since May 2026. The owners charge the system in their retailer’s free three-hour midday window, so the heat for the evening costs them close to nothing. The second was a Warragul (slab-heated home, Victoria): installed in two days in July 2026. Our controls turn the home’s concrete slab into part of the battery, managing when it charges and when it releases heat. On 95% of winter evenings, the heat pumps did not run at all between 5 pm and 9pm. Since commissioning, 70,521 MJ of gas has been avoided by just these two installations.”

Sounds like proof of concept to me.

Nick further explains: “A standard heat pump draws from the grid during those expensive morning and evening hours. You’ve escaped gas, but you’re still paying premium rates every time the temperature drops at night. Thermal Dawn is different. Our system charges when power is cheapest, a free midday window, your own solar, or late-night off-peak, then delivers that stored warmth through your radiators and underfloor heating all evening, with the compressor off through the expensive hours.

It appears that Thermal Dawn’s secret sauce is “Phase Change Materials.” Naturally, Nick declined to share exactly what Thermal Dawn is using. The system replaces a gas boiler with a combination of reverse cycle heat pump, well insulated water tank, and phase change materials. PCMs are designed to freeze or melt at a specific temperature, storing and releasing heat when they change physical state, usually from solid to liquid. “PCM doubles our heat capacity.” The heating applications I could understand, what about the cooling? “Cool water from the tank runs through a fan coil unit, and the fan blows cool air into the room. Cooling is an optional add-on.” That’s the answer.

How do thermal storage and a home battery/solar system work together? “Thermal storage is cheap storage doing one job very well. Heating, cooling, and hot water are the largest, most predictable loads in the house, and covering them thermally is far cheaper per kWh than covering them from lithium. A battery is expensive storage doing a general-purpose job.

“The practical effect is that your battery stops being the thing that carries your heating. It’s freed up for lights, appliances, the EV, and overnight backup, and it lasts longer for not being cycled hard every winter evening. Homes with a battery already are often the clearest case, because the expensive storage stops being spent on the cheapest possible job.”

Thermal dawn connects to existing hydronic pipework. The gas boiler with its high gas bills is gone. Check out the animation of heat discharge overnight. “The thermal battery charged on solar during the day and now heats the house while the heat pump stays off. It’s an illustration of what the app shows, not a recording of a live home.” For those rooms that don’t have hydronic radiators or underfloor slab heating, Thermal Dawn installs fan coil units. Nick tells me via a followup email that: “It’s a small indoor unit with a water coil and a fan: warm water from the thermal battery runs through the coil, and the fan blows the heating or cooling into the room.”

The heavy technical discussion out of the way, I asked Nick about his background. He grew up in an isolated part of New Zealand. His job was to collect the firewood for the family’s heat source — a fireplace. He had to get the fire going by 4:00 pm or the house would not warm up for the cold evening. Timing was very important, as it is for electricity use.

Nick is a mechanical engineer who has worked across tech companies and startups. While working on installing commercial air conditioning, he came across the idea that became Thermal Dawn. Nick joined the dots between the huge variations in electricity supply cost throughout each 24-hour period, with an average home’s thermal energy needs (up to two-thirds of consumption) and the fact that homes are becoming power stations. Thence to thermal batteries powered by Thermal Dawn technology.

He reminisces about the start of the business: “When our first unit was finished, we loaded it into a ute at 5pm and I drove it down the Hume overnight, Sydney to Melbourne (1000 km), to install it the next morning. We had a four-month-old at home at the time. My wife Linda is my co-founder and leads mechanical design and manufacturing, so while I was on the road, she was looking after a newborn.”

For those who would like to get involved, Nick invites Australian homeowners to sign up here and they’ll be in touch. “Readers overseas: send us a message or request a quote at the same link to register interest. If we hear from enough people in one area, we can bring forward our plans to come there.”

Having proven their point, Thermal Dawn is cleared to sell and installing its first batch now, with a larger product for ducted air conditioning in development. I asked about apartment block heating and Nick confirmed that they are looking at it but want to get the domestic home sorted first.

I asked a couple of followup questions “What about the Victorian government’s position?” Nick’s answer:  “Victoria is set to bring in support for systems like ours from the middle of next year. With the state election in November, there’s talk of a change in direction and of belt-tightening, so we’ve built Thermal Dawn to stand on its own. It saves households money without a subsidy, and any support is a bonus.”

Any plans for installs in Canberra? “Yes. Canberra is one of the best places in Australia for this: cold winters, plenty of hydronic homes, and a territory already moving off gas. We’re talking with installers there now.”

I really appreciate these technological experts when they take the time to explain things to me. Sometimes I feel like Winnie the Pooh — a bear of very little brain. Looks like Thermal Dawn has solved another part of the energy puzzle — good news for homeowners and also for the planet.