Meet Mr Humfreez

01 October 2019

We all want to live in a warm, dry home.

Not many of us know the right temperature and humidity levels to create a healthy home. The World Health Organisation recommends a healthy temperature for a home to be between 18-21°C. But the average in NZ is 17.8°C, with some as cold as 10°C. And due to excess moisture, half of all Kiwis homes have visible mould.

That’s why ANZ has created Mr Humfreez, a little sheep that helps you understand the health of your home, by telling you at a glance when it’s too damp, or too cold. Because a home should be more than a place to live, but to thrive.

Sam Archer, Director of Market Transformation at the New Zealand Green Building Council (NZGBC), says innovations like Mr Humfreez makes the cold and damp in homes visible so people can take action.

“People can often be unaware there’s a problem because they can’t always see it. We know that Kiwis are generally unaware of how unhealthy their home is, so having a device to give you an indication of just how cold or damp a home is, is a brilliant idea. Mr Humfreez has been scientifically designed to reflect the temperatures and humidity that you’d typically see in an unhealthy home,” Mr Archer says.

“At NZGBC we’ve been running the Homestar system since 2011 and it’s a rating method that shows you just how warm, dry and healthy your home is likely to be. We’re hoping to get more devices like Mr Humfreez into more Kiwi homes to help raise awareness of what to look for when buying, renovating or building a new home,” Mr Archer says.

The development of Mr Humfreez was commissioned and supported by ANZ as part of its drive to improve the health of Kiwi homes.

ANZ Managing Director, Retail and Business Banking, Ben Kelleher says, “Our research told us 59% of people didn’t know what level of humidity is healthy so we know a greater awareness of what constitutes a healthy home is needed.

“We’re committed to helping Kiwis enjoy healthier homes and believe Mr Humfreez can help us do that. We’ve already created a range of initiatives such as a $5,000 interest free home loan top-up for heat pumps and insulation and pledged $100 million of this interest-free lending to help warm up Kiwi homes.”

Mr Humfreez is the latest in a range of ANZ initiatives to help Kiwis into healthier homes. You can check out “How Mr Humfreez Works” here


Mr Humfreez goes blue in the face when the temperature dips below the healthy level of 18°C.

‘Thermochromic’ ink on his face allows Mr Humfreez to react to changes in temperature. This specially made ink appears colourless when conditions are warm. When the room gets colder than 18 degrees, the blue ink shows its true colours.


To prevent mould growth, the amount of moisture in your home (relative humidity) should ideally be below 65% most of the time. This is why Mr Humfreez warns you by uncurling his horns when the moisture in the air exceeds 65% (relative humidity).

Mr Humfreez's specially designed wooden horns are ‘hygroscopic’ – meaning they can sense and react to moisture in the air. Wood does this naturally (ever notice how timber warps when wet?)

Kiwi at heart, with global smarts.

ANZ created Mr Humfreez to help Kiwis keep an eye on the health of their home. A digital thermometer/hygrometer would have done a similar job, but they wanted to make something that was smart and sustainable in equal measure.

The technology behind Mr Humfreez is the brainchild of Professor David Correa and his team at the University of Waterloo in Ontario, Canada.

They developed the programmable hygroscopic horns that allow Mr Humfreez to respond when the air gets too humid. And they helped formulate the special ink that makes his face change colour when it gets too cold.

If you think your home is too humid, or lacks adequate heating, check out our range of initiatives to Help Kiwis live in warmer, drier homes.

  • Interest-free home loan top ups for heat pumps and insulation.
  • Healthy Home Loan Package
  • HomeFit check.

  • For more information visit the ANZ Healthy Homes website