One of the largest low-energy housing projects in the UK and Ireland is nearing completion in Belfast.
The 219-home development at Lancaster Park is being built to Passivhaus standard.
Passivhaus or 'Passive House' is a building standard whereby the finished home uses very little energy for heating and cooling.
Rising fuel bills in his own home kickstarted project director John Carrigan's journey to adopting this approach to building.
He said: "Some time ago, in my own house, I noticed my oil bill doubled within the course of a year. It occurred to me, I am fortunate, I can afford it. But there are a lot of families out there and how on earth can they afford this fluctuating energy bill?
"So, I just researched and researched. I didn’t invent anything new. I just found out the best way to spend less money on heating a house is to keep the heat in the house. The best way to do that is to build ultra-low-energy houses. The gold standard of low-energy housing is Passivhaus."
John took the idea to his employers, Fraser Millar Homes. The developer agreed to adopt Passivhaus standards at Lancaster Park.
"Passivhaus Institut is a building standard created in Germany. It works off five key principles - triple-glazed windows and doors, eliminate thermal bridges, increase insulation, superior air tightness and installation of a mechanical ventilation with heat recovery system.
"The idea is that somewhere in the region of 98% of the heating that you put into your house, we keep that heat in the house and we use it to heat the rest of the house. And that means very low heating bills, more stable indoor temperatures, and improved indoor air quality."
John estimates one of the development’s three-bedroomed homes will cost £450 per year for all its hot water and heating needs.
He said: "It’s as close to fixed as you can get it really. You can’t unknow something once you know it. We now know how to build the best energy efficient houses. You’d be a fool to want to go back to building something that’s leaky and costly."
By his own admission, John is not ‘Mr Climate Activist’, but he is "doing a bit more, each day and each year."
He said: "We could have built these homes to the most basic standards. After all, this is one of the most sought-after sites in Belfast. But I have a desire and a passion to step things up in the housing industry. Maybe we owe it to the next generation to give them something better. I think we all have a duty of care to this planet."
In our 'Climate Heroes' series of reports, we shine a light on the people who are stepping up to protect our environment and tackle climate change.