- Owners and Builders
To allow fair comparisons between homes, NatHERS software models heat loads based on conditions under which occupants are most likely to be thermally comfortable within their home.
These conditions vary according to many factors including:
To allow homes to be compared fairly a standard occupancy pattern is applied that represents a reasonable expectation of how each space in that home is used, based on its function.
For the purpose of assessing a building under NatHERS, the software allocates functions to each space in a home, along with a period of time during which the space is likely to be used and required to be kept at a comfortable thermal range. For example:
NatHERS software adjusts modelled temperatures to achieve thermal comfort through three means:
All external openings (e.g. windows) are considered to be operable at all hours, although a factor has been incorporated to limit the number of operations to one per each three hour period.
The heating thermostat setting varies according to the function of the space and the expected clothing level in that space during a particular time period. For example, a lower minimum heating thermostat setting is used during sleeping hours to reflect the likelihood of bedding (sheets, blankets, quilts etc.) being used.
The cooling methodology is based on the Effective Temperature method of calculating thermal comfort. The cooling thermostat setting varies according to the climate zone to account for the acclimatisation of local residents. It also varies from room-to-room from the summer neutral cooling temperature of that climate zone to take into account the effect of air movement, air temperature and humidity level in that space on the occupants' perception of thermal comfort.
Further details about the specific thermostat settings for each NatHERS Climate Zone can be found in the NatHERS Software Accreditation Protocol