Startup Ona has launched a €165 plug-and-play kit that runs air conditioners when power is cheap and stores the heat in a home's walls, and estimates average savings of €275 a year for a terraced house.
Credit: this report is based on a story first published by IO+. Read the original at ioplus.nl.
According to IO+, Ona was founded in 2025 by Alexander van der Linden, Bart Kramer and Stefhan van der Kemp, who had met at Lightyear. The idea came out of physical simulations of other concepts, such as storing heat in a water tank, when the team saw how much warmth an ordinary house keeps in its concrete. A water tank system would have cost thousands of euros.
The product
The kit has two parts. The Energy Hub plugs into the meter cupboard, tracks how much energy the home uses and produces, and pulls electricity prices, weather and solar irradiance forecasts over the internet. It controls the Airco Controller, a smart remote for an air-conditioning split unit, and pairs with a mobile app.
"It's actually a hack to make those devices smart," says Van der Linden.
Users set a preferred temperature range in the app and the system stays within it. The Energy Hub also learns how quickly each house loses heat and adjusts how early it starts heating. Ona has tested the system for more than a year in several houses.
The numbers
Ona estimates that a terraced house saves €275 a year on average compared with the same household without smart control. If the air conditioner also replaces gas boiler heating, savings can double to around €540 a year, the company says. Its online simulator covers 108 house setups, and in none of them did first-year savings fall below the price of the kit.
Van der Kemp says gas cost around €1.20 per cubic metre when the team started and is now closer to €1.70 to €1.80. Even at average electricity prices, heating with an air conditioner is one and a half to two times cheaper than a gas boiler, he says.
Timing and market
The launch comes ahead of 1 January 2027, when the Dutch net metering scheme for solar panels ends and midday solar power will be worth far less to the households producing it. According to research institute TNO, 19% of Dutch households, roughly 1.6 million, use their air conditioning to heat their homes.
Ona is aiming at households that cannot afford another thousand-euro outlay on a home battery. The team is already working on an energy thermostat that could become a central control point for a home's energy use, while the founders say their focus for now is steady growth.
Original source: IO+, "No home battery needed: Ona stores cheap heat in your walls"
