Sun, heat, rain and fire in Perth
Hot days
Wikipedia gives Perth an average of five days a year above 40 °C. Your Home says roof glazing receives almost twice as much heat as an unprotected west-facing window of the same size, so an oversized skylight can cook a room.
Clear skies
Your Home says tubular skylights work best in sunny, clear climates, while conventional skylights and roof windows suit cloudier places. That tips the balance toward tubes in a lot of Perth homes.
Winter rain at the flashing
Most of Perth's rain falls in June, July and August. A skylight is a hole in the roof, so the flashing around it is where a winter leak often starts.
Bushfire prone areas
Your Home notes that in bushfire areas, skylights must comply with AS 3959 for the home's BAL. Perth Hills homes in a mapped area should check before choosing a product.
Tubular skylight or roof window?
| Tubular skylight | Roof window | |
|---|---|---|
| What it is | A small roof dome and a reflective tube down to a ceiling diffuser | A framed glass window set into the roof, often with a light well |
| Heat in summer | Less, because the opening is small | More, unless the glazing and shading are good |
| Fresh air | No | Some models open, manually, electrically or on solar power |
| Suits | Hallways, bathrooms, laundries and walk-in robes | Living areas, kitchens and raked ceilings |
How big, and where?
Your Home suggests a skylight area of about 3 to 5% of the floor area for conventional skylights and roof windows, and only 1 to 2% for high-performing tubular skylights. Solatube says its 250 mm model lights about 19 m2 in the right conditions.
Keep big glass away from the western sun, and ask about the glazing's U-value and SHGC (how much heat it lets through), which the Window Energy Rating Scheme publishes for skylights. Solatube warns never to tint its skylights, because it creates a fire hazard.
On an older home, check before cutting in. ASSEA says old skylights and roof manholes may contain asbestos cement.
Ask before you choose a skylight
- Which way will it face, and how much afternoon sun will it get?
- What are the glazing's U-value and SHGC ratings?
- How will you flash it into my tiles or metal sheeting?
- Does it need to meet bushfire requirements where I live?
- Who warrants the product, and who warrants the installation?
Our pick for Perth
For a dark hallway, bathroom or laundry, we'd go tubular: lots of light, a small hole in the roof and far less heat. For a living area, we'd only fit a roof window with good glazing and a blind, kept away from the western sun and sized on the small side.
Want a roofer to take a look?
Tell us the job and your postcode. We match it with a Find My Roofer certified roofer who specialises in that kind of work, and they call you to quote. Your number goes to them alone.
Send us your postcode and which room you're thinking of. If we have a licence-checked roofer who fits skylights in your part of Perth, we'll pass your job to them only, and if we don't, we'll tell you straight away. The skylights page has more, and Perth lists other jobs.