Mr Hoerning said the figures were encouraging but there was still a lot of cold, damp houses in New Zealand with substantial work to be done and people contemplating energy efficient renovations should tackle insulation first.
The biggest mistake made by renovators was "focusing on aesthetics", rather than fundamentals, he said.
"For example, that may be a beautiful kitchen bench or paint colour without fixing the fundamental things like insulation, ventilation and heating that make a house warm, comfortable and healthy to live in."
Statistics from the authority showed there were more than one million visits a year to its website www.energywise.govt.nz, Mr Hoerning said, and it was a helpful site to search for up-to-date information and tips.
It covered a huge range of topics including energy rating labels on new appliances.
"Energy rating labels provide information on how much energy a product uses, making it easy for you to compare the energy efficiency of similar appliance models.
"For example, an Energy Star qualified fridge/freezer could save you up to $900 over its lifetime ... the more stars on the label, the more energy efficient the appliance is."
When people tackled renovations it was a great opportunity to look at energy efficient solutions, he said.
"If you are taking off the wall linings in a bedroom you could look at wall insulation (which will need a building consent) or if you are painting the ceilings you could think about what type of lighting you want."
Even simple changes like using energy efficient light bulbs could save you money, he added.
Supermarket sales of energy efficient light bulbs increased from three per cent in 2003 to 26.8 per cent in 2015, Mr Hoerning said and they used up to 80 per cent less energy than standard incandescent bulbs.
Hometech Solatube owner Tim Rooney said utilising natural light in dark spaces could also reduce energy usage.
Its solar tubes were often used by people contemplating renovations and it had installed them at schools in Papamoa.
"You won't need the lights on during the day and a lot of these rooms require that. It also accentuates the feeling of space and warmth."
Kiwibank communications manager Bruce Thompson said it started its sustainable energy loans in 2012 and they had proved popular.
It offered to contribute up to $2000 over four years to customers that got a home loan to purchase solar power, wind energy, hydroelectric and domestic geothermal systems, he said.
Down to Earth - Sustainability & Lifestyle Expo takes place on November 28-29 at ASB Arena, Mount Maunganui.
Useful Websites
www.energywise.govt.nz
www.consumer.org.nz
www.communityenergy.org.nz
www.building.govt.nz
