The availability of Solar Gard Ecolux 70 window insulation product into the New Zealand market has meant new ways and reasons to consider when thinking how could such a thin product provide window insulation properties.

The secret is gold that is part of this product and specifically a function of gold which is its emissivity. Emissivity is the ability to reflect radiation (energy). It’s why you often see satellites coated with gold, it has a natural ability to reflect energy.

The emissivity of gold is around 0.03 so what that means is it wants to reflect 99.7% of the energy back!

In comparison the emissivity of glass on its own is around 0.82 meaning it can only reflect 18% of the energy and hence why glass on its own is not a good insulator.

“This great news when you are considering installing an insulation product that provides all year round benefits ,365 days/24 hours” says Mr Ross Eathorne ,Managing Director of SWF Distribution that company that imports and distributes Solar Gard window film. He goes onto say that this is a cost effective solution causes no inconvenience to customers and is supplied with a manufacturers limited life time warranty.

When Solar Gard sputter gold onto a film they do it extremely thinly so it can still transmit the visible light (so you can see through it) but it retains its ability to reflect what’s called far infrared energy. Far infrared energy is what comes from a fireplace or a heater in the home and by having the thin layer of gold on the glass we are able to selectively reflect that type of energy (heat) back into the room.

So it’s the inherent emissivity property of gold that provides insulation ability and it doesn’t need to be thick, in fact making the layer thicker will not make it more reflective of the energy.

This type of insulation through emissivity is a different way to insulate versus double glazing or roof insulation batts. Those types of insulating products use a combination of different materials and air pockets / layers to make it hard for the heat energy to pass through. Every time the energy encounters another material it has to change its wavelength to pass through it so when you have 2 layers of glass plus an air gap in between or you have a fibrous roof batt which is layers of fibreglass with many air pockets it is hard for the energy to pass through and so you are not losing as much heat. This type of insulation is not reflecting the energy, think of it as trapping the energy so more can’t get through and escape.

Thermodynamics can be a very complex area and we understand it is hard to grasp that a thin sheet of film can provide high insulation ability but it’s all to do with the gold and its special properties.

As something to refer to as an example of this ,there is good reason quality kettles are shiny metal. They are polished because it makes the metal lower emissivity so it keeps the water inside hotter for longer.

Eathorne comments that home and building owners need to be more open to new technology and the fact that there is more than one option to achieve a result. The shiny kettle example is a good example. You don’t see kettles with a thick outer casing that incorporates an air gap. Shiny kettles have been around a long time and Ecolux 70 with gold just takes this a stage further. You don’t need to necessarily have installed insulation product that is thick and bulky.

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