Skylights

In this article

1. Skylights

Light house

Skylights are a great way to reduce energy consumption and let the sun shine into your home. Skylights come in many shapes and sizes – from tubes to atria – so it is important to choose the best one for your house.

Design

Skylights increase the amenity of the home and add flexibility to architectural design. Skylights let about three times more light into the home than a similar size vertical window and continue to work effectively during overcast conditions. There is a variety of designs to suit varying roofs.

Size

Correct sizing of your skylight will ensure just enough light enters the home – no more. There are several ways to decide on the size and location of your skylight and you could also rely on the window energy rating system (WERS) as a guide to energy rating for skylights. In temperate Australia, the size of skylights will be contained to limit unwanted solar heat gain. Contact your retailer for installation advice.

Spacing

Skylight spacing is important in large spaces so you can get the maximum benefit. Most skylight distributors include this service as part of customer care. Solatube supply a product calculator, in the form of a questionnaire, on their website that recommends the best skylight to suit your home.

Solar control

In warmer climates, skylights can let in unwanted heat when skies are clear, so try to incorporate energy-efficient design technologies, such as glazing. Glazing will block or transfer light to reduce the impacts of direct sunlight. Use other design features such as tubes, shafts, ceiling diffusers and blinds to assist with solar control and prevent glare.

Types

Plastic dome skylights are usually single glazed ‘opal’ (diffuse) moulded units. Specular top glazing may also be employed, either in clear or tinted plastic. Plastic dome skylights typically have long shafts and a diffuser panel fitted at ceiling level.

• Larger skylights suited to overcast conditions

Roof windows are popular for attic rooms where there is a cathedral ceiling but no roof space. Sealed double insulating glass is used, to reduce heat losses, and some can be opened, which enables hot air to escape during the warmer months. To avoid fogging, some double-glazed units are permanently ventilated, but that could cause draughts and heat loss.

• Suited to overcast conditions

Tubular skylights work by capturing direct-beam sunlight and diffusing it at ceiling level around the room. A reflecting tube directs sunlight downward, which works most effectively if the tube is straight; has a silver lining and a visible reflectance of 95 per cent or more. Flexible tubes are effective if their internal reflectance is high. Diffusers should be fitted to tubular skylights to reduce glare and throw the light over a broad area.

• Suited to sunny climates.

Maintenance

Regularly clean external and internal surfaces with soap and water using a sponge or brush, to maximise performance. Rinse detergent off with clean water. Clean every couple of years, but if in harsh climates, every six months. Operable and ventilating skylights could require occasional lubrication of moving hardware. Don’t allow leaf debris to pile up on skylight materials as rainwater leaches decomposed chemicals out of the leaf litter and causes staining.

Consult your manufacturer for specific maintenance requirements to ensure your skylights long-term performance.

Window Energy Rating Scheme (WERS)

The window energy rating scheme (WERS) ranks windows’ energy performance in housing across in Australia and can tell you if a window is suitable for the climate. Windows are rated from 0 to 5 stars for heating and cooling and WERS complements manufacturer's standards for wind, water penetration and safety (AS 1288 and AS 2047). The windows are then rated and labelled for their energy and comfort impact on an entire house – the more stars – the more energy efficient.

Skylight Energy Rating Scheme (SERS)

Some manufacturers are also using a Skylight Energy Rating Scheme (SERS), which provides similar information to WERS that is adjusted to skylight heating and cooling performance and day lighting performance.

WERS ratings will be less accurate if there are very large glass areas where the total glass area is greater than 35 per cent of the floor area, such as sunspaces, attached conservatories and large skylights.

Windows will carry a sticker certifying that the window has been energy rated. The star ratings are shown at the top of the sticker; heating performance is shown in red and cooling performance is shown in blue.

Reference: Your Home, design for lifestyle and the future (Australian Government).