The energy efficiency requirements of the NCC are becoming more stringent each passing year. During the 90’s most houses would average a 1-star energy rating and as of May 2012, it became mandatory for all proposed developments to comply with a minimum 6-Star housing energy rating. Most of our clients at Energy Rating Perth who are extending or altering their buildings are worried they would have to make changes to their existing homes as well. The energy assessors at Energy Rating Perth would like to pacify our readers that this is not the case, there are two energy ratings taken i.e. one for the existing and one for the existing plus proposed and the overall energy rating is a ratio of the two achieving an overall 6-Star energy rating home.
In theory, most building designers might include energy efficiency through an appropriately designed thermal performance on their buildings. However, in practice, when these designs are received by the energy assessors at Energy Rating Perth, we can see the potential design issues as well as problems that may arise during construction which would eventually lead to a poor thermal performance. This can result in design flaws or even building defects that are as follows:
- Alterations to your existing doors and windows or adding to the floor area changes the nature and performance of your building’s glazing and may result in a lack and/or excess of visible light transmittance and/or solar heat gain.
- Poor construction joints between the old and new can result in air gaps in the building envelope which results in air leakages and draughts.
- Introduce unwanted ventilation into closed spaces and allow the warm inside air to escape in winter.
- Inadequate ventilation due to a lack of openings in the proposed development will result in reduced natural ventilation for the entire building in summer.
- Inadequate or poorly installed insulation resulting in a poorly performing building envelope encouraging heat loss/gains.
- Condensation can occur due to a lack of vapour barriers or improper building sealing which can greatly affect the internal thermal comfort.
Overall, inadequate thermal performance in one aspect of the building can have detrimental effects on the entire building. At Energy Rating Perth, we urge our clients to employ energy assessors early in the project so they can guide the builder/designer during the design process to avoid expensive errors that have to be corrected later. If you suspect your otherwise energy efficient home might be underperforming after an addition or alteration, then it would be wise to get it re-assessed by a professional energy assessor to help you get a better energy rating and have a more energy efficient building in the future.