Articles in this issue


Welcome to the seventh edition of the NatHERS Star!

This year's achievements

It has been another busy year for the NatHERS Administrator.

NatHERS Stats

Recent data on the NatHERS Certificate.

Fraudulant NatHERS Certificates

Recently the NatHERS Administrator has received, and been following up on, a number of NatHERS Certificates that have been suspected to be fraudulent.

NatHERS Assessor Handbook

The production of the NatHERS Assessor Handbook is well underway.

NatHERS at Sustainable House Day

Sustainable House Day was held on Sunday 16th September 2018.

Modelling obscure glass

It has been brought to the attention of the NatHERS Administrator that there is industry confusion as to how to correctly model obscured glass in NatHERS accredited software tools.

Update on Windows

The NatHERS Administrator continues to actively work on improvements to address concerns regarding windows.

Chenath updates for 2019

The Australian Building Codes Board (ABCB) have approved the following updates for the Chenath engine in line with the 2019 update to the NCC.

Trajectory for low energy homes

Australian governments are advancing the energy performance of residential and commercial buildings through the development of a Trajectory for Low Energy Buildings.

When to contact Who?

A quick guide on where to direct enquiries.

NatHERS myth buster: thermal mass

An insight into the thermal mass formulas used by the NatHERS calculation engine. 


  • Your Home
  • BDAV 2018 Design Awards

NatHERS myth buster: thermal mass

Thermal mass is a material’s ability to heat or retain heat over time and is based on the conductivity, density and specific properties of the material. High thermal mass, like a masonry box, means it is less impacted by changes in external temperature compared to a lightweight timber box.

The thermal mass formulas used by the NatHERS calculation engine (Chenath) were developed from 1953 work by former CSIRO scientist Dr R.W Muncey’s. As you can see in the results below, Muncey’s experiments showed a construction having high thermal mass was less impacted by changing external temperature, both in actual observations and predicted modelling.

Thermal mass is a fundamental element considered in NatHERS software tools. The software calculates how much heat is transferred and potentially generated in a dwelling by considering its orientation and construction (the construction material properties that include thermal mass) combined with occupancy settings, and hourly climate data of its location. This information simulates an internal temperature. If that temperature falls or exceeds the thermostat setting for heating and or cooling, the software triggers a calculation of predicted energy use that would be required to maintain the internal temperature within the thermostat limits.

View the full paper by Dr R.W Muncey’s work here: The Calculation of Temperatures Inside Buildings Having Variable External Conditions