Is Metal Roofing Good in Hot Weather? How a New Colorbond Roof Keeps Your Central Coast Home Cooler

A metal roof does not have to make your house hotter. How hot the rooms under a new metal roof get in summer depends on the roof colour, the coating on the steel, the insulation under the roof and how well the roof space is ventilated. Get those four right and a metal roof suits the hot summers we get on the Central Coast.

Do metal roofs make your house hotter?

A metal roof on its own does not make your house hotter. The metal sheet on the roof gets hot in the sun, which is why it’s easy to assume a metal roof means a hot house. What decides the temperature inside is how much of that heat reaches the roof space and then the ceiling below it.

The Australian Government’s YourHome guide to passive cooling puts it simply: “The use of foil insulation and light-coloured roofing limits radiant heat flow into the roof space.” In other words, the colour of the roof and what sits underneath it do most of the work.

A dark roof with no insulation will heat the house more than a light roof over good insulation. That holds for any roofing material, metal or tile.

What is a cool roof?

A cool roof is one that reflects more of the sun’s energy, so the roof surface stays cooler in bright sun than a standard roof would. Less heat in the roof surface means less heat passing into the roof space.

Colour is the obvious part. Lighter colours reflect more sunlight than darker ones. The coating on the steel is the less obvious part, and it is where Colorbond’s Thermatech technology comes in.

How does Colorbond Thermatech help in hot weather?

BlueScope, the maker of Colorbond steel, says in its March 2023 article on cool roofing colours that “Thermatech® technology increases the solar reflectance properties of COLORBOND® steel and helps keep buildings cooler in the daytime.”

The same article says Thermatech is available in each colour in the Colorbond core roofing and walling palette, in the Classic and Matt finish, including the darker colours, with the exception of Night Sky. That means you are not limited to white or cream if you want a roof that handles the heat well.

BlueScope is also clear that the outcome varies from house to house: “Results will depend on roof colour, roof shape, level and location of insulation, type, location, shape, and function of the building.” A cool coating helps, but it works alongside the insulation and ventilation, not instead of them.

What is the best metal roof colour for a hot climate?

Lighter colours keep a roof cooler. BlueScope’s March 2023 article lists eleven cool roofing colours in the Colorbond core range, including Dover White and Southerly. Surfmist and Classic Cream are two light colours you can see on our Colorbond colours page.

Darker colours such as Woodland Grey or Ironstone will run warmer than the light shades, even with Thermatech. You might still prefer a darker colour because it suits the house and the street. If you do, good insulation under the roof matters even more.

A colour can look quite different on a small swatch than on a whole roof in full sun. You are welcome to see the actual colour samples at our showroom at 3/3 O’Hart Cl, Charmhaven, before you decide.

Why insulation and roof space ventilation matter under a metal roof

Even a light, reflective roof still gets warm in a Central Coast summer, so what sits under the roof sheets decides how much of that warmth reaches your ceilings. Insulation slows the heat down. Ventilation lets hot air out of the roof space before it builds up.

The YourHome guide describes a well-ventilated roof space as a buffer between the inside of the house and the outside, in “the most difficult area to shade: the roof”. It also notes that “ventilators such as whirlybirds can reduce the temperature differential across ceiling insulation, increasing its effectiveness.” If you want to read more about roof ventilation, our guide to whirlybirds and passive roof ventilation covers it in detail.

The National Construction Code sets minimum insulation levels for roofs, walls and floors according to your climate zone, as the YourHome guide explains. When you are planning a new roof, it is worth asking what insulation is going in under the new sheets.

Is a metal roof better than a tile roof in hot weather?

Both roofs can be hot or cool, depending on colour, insulation and ventilation. The YourHome guidance on light-coloured roofing and foil insulation applies to tile and metal alike. With a new Colorbond roof, you can pick a colour from the core range with Thermatech and plan the insulation and ventilation at the same time as the roof.

Tried patching your tile roof more than once and it’s still leaking? That’s the time to look at a tile to metal roof conversion, and choosing a cooler colour becomes part of that decision. Our article on metal roofing versus tile roofing compares the two in more detail.

Can a cooler metal roof lower your air conditioning use?

It can help. Less heat coming through the roof means less work for the air conditioner on hot afternoons. BlueScope’s article does not give a set saving, and it says results depend on roof colour, roof shape, insulation and the building itself.

A light, reflective roof over good insulation and a ventilated roof space gives your home the best chance of staying comfortable without running the air conditioning all day.

Planning a new metal roof for a cooler Central Coast home

If you are replacing an old roof, a new roof is the best time to think about heat. You choose the colour, the coating and what goes underneath all at once, and you live with that choice for many years.

AWS Roofing installs new Colorbond metal roofs and full roof replacements across the Central Coast. We are a licensed roofing contractor (licence 247575C), fully insured and WorkCover accredited, and every job is backed by a written warranty.

Have questions about a new roof and how hot it will be? We’re happy to chat. Get in touch for a free, no-obligation quote, or pop into our Charmhaven showroom to see Colorbond colours in person.

Sources

• Australian Government, YourHome: Passive cooling (retrieved 7 October 2026)
• BlueScope: Cool roofing colours: innovative BlueScope technology, March 2023 (retrieved 7 October 2026)