Windows are the link between the internal and external environments of your home, connecting you to your surroundings whilst keeping the harsh heat or cold out. Unfortunately, if you position your windows poorly, they can have the opposite effect, increasing the solar radiation that enters your home whilst reducing the amount of shade and cooling the structure can provide. Most recent estimates are that 40% of a home’s heat can be lost through poor window choice, while you can increase the unwanted heat in your home by 87% due to the same poor choices.
By incorporating passive solar designs into the home, we can achieve greater thermal performance and make it a more comfortable place to live. Here are a few quick tips.
- Locate and size your windows to let the sun in when it’s cool and keep it out when it’s hot
- Use thermal mass to store the day's heat allowing for comfortable night-time temperatures.
- Seal openings to reduce draughts.
- Position your windows and doors to allow natural cooling by cross ventilation.
Although they sound simple the tips above may become complex when you begin to take into account the local climate, adjoining properties and the views available from the property. Where orientation is not able to be engineered to allow for best performance, we can apply various levels of glazing to reduce or enhance the solar radiation in a dwelling.
Glass products vary greatly in their ability to reflect and transmit heat in any given circumstance. Despite what you may think, the thickness of the glass makes minimal difference to the thermal properties of it, although it does have large impacts on noise transmission, strength and safety.
Glazing can be split into multiple categories.
This is regular glazing with coloured additives introduced to the glass during production.
Low Emissivity Glass
Hi Transmission/Low E glass has a coating that allows daylight to pass from the sun whilst reducing the heat that can escape.
Low Transmission/Low E glass has a coating that reduces solar heat gain whilst still allowing daylight to pass through.
A thin layer of plastic sits between two sheets of glass to prevent large shards of glass forming if there was to be an accident.
Insulated Glass Units (IGU’s)
This is a combination of 2 or more layers of glazing secured within a sealed unit.
Retrofitting of a secondary acrylic or glass sheet to introduce an air gap improving noise control and U value.
Picking the most efficient orientation may sound simple but it's not. There are several elements to be considered especially when designing a home with the intention of making the most of the views and surroundings while considering local climate and weather patterns.
By choosing the right orientation you can limit or negate the need for auxiliary heating and cooling resulting in lowered energy bills, reduced greenhouse gas emissions and improved livability. Considering the usual direction and type of winds along with the sun's path throughout the year across the equinox and the solstice you can have a serious impact on the cost of running your home.
There is no one size fits all for orientation as it depends on a multitude of factors but here are some basic tips to help get you started.
- Where possible choose a site that runs north south with living areas in the north and bedrooms in the south to make the most of the daytime.
- If you have an East-West block, ensure you have wide north facing outdoor areas.
- Build as close to the southern boundary as possible to ensure maximum northern exposure.
- Ensure there is minimal excess glazing on the western side.