Appropriate window coverings can provide enormous benefits to the energy efficiency and comfort of our homes. Indoor blinds can create an insulating layer of air inside the glass to retain heat in winter, or provide a shading effect which reduces solar heat gain during summer.
High quality cellular indoor blinds can provide a lot of advantages. Their unique honeycomb structure traps air, enhancing their insulation properties to better regulate indoor temperatures with lower heat loss (or gain).
Exemplary Energy’s consulting team has been engaged by one of the major suppliers of cellular blinds to model and assess the energy performance benefits of a home that has windows furnished with a range of blinds.
We have selected a design from the publicly available set of de facto standard designs used for interpreting the impacts of construction changes as modelled by house energy rating software packages in the Nationwide House Energy Rating Scheme (NatHERS) which assume the poorly performing light-coloured Holland blinds in rating mode. The house was modelled with NCC-compliant Deemed to Satisfy (DTS) ceiling, wall and floor insulation, concrete slab-on-ground floors, brick veneer external walls and plasterboard internal partitions, and (separately) a 6-star version – between them, these broadly reflect the energy efficiency of homes built in recent years. For each of these, two types of window were modelled: a clear single pane glass commonly used with standard aluminium frames and also a generic double-glazed window with thermally enhanced aluminium frames.
For each of the four configurations, the heating and cooling energy demand of the home was calculated assuming the standard NatHERS occupancy of a 4-person household using the 2023 version of the NatHERS software.1
We applied the results (energy consumption) to a gas central heating system model which assumes a system efficiency of 61%, and (again, separately) to a heat pump space heater with a coefficient of performance (COP) for heating of 3.7 and COP for cooling of 3.3.
Scope 1, 2 and 3 greenhouse gas emissions were estimated using the emissions factors published in the Australian National Greenhouse Accounts Factors: 2023.
Results from previous work suggest that heating savings of up to 50% (compared to a 6-star baseline home in Sydney) might be feasible with the highest performing products.
We look forward to bringing you more details of our findings in a future edition of this blog.
Notes:
1. This occupancy is known to overestimate the energy consumption of the average household so our report will include commentary on the likely impact for real families.