Why window selection is vital for an accurate energy rating

April 2018

Wayne Floyd – Director of Floyd Energy

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Why window selection is vital for an accurate energy rating

How much emphasis should be on window selection when assessing a building design for a 6+ Star Energy Rating Report?

For us at Floyd Energy®, the type of windows selected in a design is one of the first considerations to ensuring we deliver an accurate energy rating that will result in a house/building that is energy efficient, has thermal comfort and saves on long term occupier costs.

Watch any of the multitude of home design and improvement TV shows and it would be easy to believe that delivering on building sustainability is as simple as installing double glazed windows. But, for an expert in thermal performance, we know it is never as simple as this.

When selecting windows for a project, consideration needs to be given to the contribution of the window to both the heating and cooling loads of each design.

As an example, clear double glazing keeps in thermal warmth in winter but it does the same in summer, meaning a warmer building in both winter and summer. Not ideal for the occupier’s thermal comfort year round; nor for their cost of living.

Whereas a double glazed window which has a low e coating, either soft or hard on surface 2 or 3, will reduce the amount of heat entering the building in summer and also reduce internal heat losses in winter.

We understand quality window selection is often the expensive option for a development and can be difficult to explain to the client, but it’s an Energy Rater’s job to communicate the upfront expense will deliver long term savings and comfort that will (also) likely contribute to a more valuable building in the future.

And, beyond the long term results, accurate assessment of windows as part of an Energy Rating Report means a document that’s not only compliant for a building permit, but buildable.

Too often we see generic window choices in a rating report, without consideration given to operating type and often chosen to manipulate data to generate a 6+ star rating. The result being windows that are difficult (or even impossible) to source for the build – adding hidden expense in building delays and needing second a rating.

And once the window selection is changed, the 6 Star rating quickly disappears to a non-compliant build.

Floyd Energy® wants to lead the building industry to have the courage and foresight to implement best practice and stand by the principle that profit should never be at the cost of occupiers’ wellbeing, safety and comfort. It should not be at the cost of great design and quality buildings.

Profits should not come at the cost of the humans who will occupy the space.

What’s the adage? You have to spend money to make money…

Don’t get us wrong, we understand budget can be limited for developments; we work with clients where some sustainability and design features must be compromised and there are alternatives. These compromises may include recommending the use of a different floor slab that’s more cost effective than high quality windows.

Ultimately we need to educate on the importance of window selection to building sustainability, energy efficiency and thermal comfort. Energy Raters need to be better than handing over a document that leads to low quality buildings that are leading to poor occupier health, comfort, high energy bill costs and, sometimes, more dangerous repercussions.

www.Floyd Energy.com.au