Nelson Lebo describes himself as a 'house doctor' and through his work as an Eco Design Advisor in Palmerston North, he's 'diagnosed' more than 2000 homes in the central North Island.
His role there is to help people manage their homes more efficiently, especially during winter.
"The house doesn't come with an operating manual," Lebo said.
"It's one of our most expensive, biggest investments that we spend the most time in, and there is no operating manual."
Nelson and his wife Dani Lebo run an eco-school near Whanganui where they teach a certificate in permaculture. They're now ready to take their 'house doctor' service nationwide.