Can using glass in design really provide energy efficiency?


Choosing the right type of glass has long since been a key element to consider when designing or refurbishing a space. The clarity and aesthetic nature of glass is unmatched in its ability to not only provide natural light, but to also create stunning architectural facades. However, with up to 40 percent of a home’s heating lost, and more than 87 percent of it gained through windows alone; the thermal performance in glass is a crucial element to consider when cutting down on energy costs and consumption. The right type of glass possesses the unique ability to retain heat in the winter, all the while ensuring that your home is also kept cool in the warmer months. But with Australia’s widely diverse and varying climate, it can be both difficult and time consuming to select the right type of glass for the application.

The right type of performance glass can make your home more comfortable, dramatically reduce your power bill and is critical to a building’s energy efficiency. In most cases, regular windows - notorious for unwanted heat loss and gain - are not adequate enough for current home designs, let alone to meet today’s stringent building regulations. By specifying the correct type of performance glass for your project; studies show that you can increase a building’s energy-efficiency by up to 2.5 stars simply by switching out ordinary aluminium single glazed glass. A common misconception prevalent among consumers is that performance glass products are an expensive way to increase energy efficiency in buildings. However it is important to consider that windows - even ordinary ones - make for a relatively high-value component of a building, meaning the investment could be the difference between owning a high value property or one with a lower valuation.

Windows, doors and skylights can gain and lose heat through:

_The radiation of heat into a building and out of a building from room-temperature objects, such as people, furniture, and walls
_Direct conduction through glass or glazing
_Air leakage

These properties can be measured and rated by considering two distinct heat transfer mechanisms: conduction and solar heat gain. The conduction - or U-value - measures how much heat is transferred through the glass. The lower the U-Value, the better the insulation properties of the glass, the more adept at keeping the heat or cold out. The solar heat gain - or SHGC - looks at how much solar radiation passes through the glass. The higher the SHGC rating, the more radiation passes through, the more you can benefit from free thermal heating. All in all, paying special consideration to the U-value and SHGC rating of performance glass products ensures that a building’s occupants remain thermally comfortable, without having to resort to artificial heating or cooling methods.

One of the key developments in glass efficiency has been the technological advances in low-e (low-emissivity) glass products over the past two decades. Coated in microscopic layers of metallic oxides, low-e glass is designed to let in as much natural light into a building as possible, all the while retaining and controlling radiant heat (infrared light) as it enters and leaves a room. The use of low-e glass products contributes significantly to a building’s energy efficiency, yielding excellent results for both solar control and thermal insulation.

While energy bill savings are an obvious benefit associated to reducing artificial heating or cooling, the health and productivity of building occupants can also be greatly affected. With workers typically spending upwards of eight hours a day in air-conditioned buildings; minor yet irritating health concerns such as: respiratory tract problems, allergic reactions and viral and bacterial infections can occur. Utilising the right type of performance glass can greatly reduce the need for auxiliary temperature control, reducing the risk of spreading sickness, as well as increasing overall productivity and happiness in the workplace.