El Niño summer: how to block heat from west-facing windows in Hunter homes

The short answer: shade the west-facing glass first

If you shade one window before summer, make it the one that faces west.

Two federal government guides put windows at the centre of summer heat gain. Your Home says up to 87% of a home's heat can be gained through windows. Energy.gov.au puts it at "almost 90% of a home's heat". And of all that glass, Your Home singles out one side: "West-facing glass and walls are a significant source of heat gain in hotter climates".

The fix it points to is shade. Direct sun can put the same heat as a bar radiator over each square metre onto a surface, but effective shading can block up to 90% of this heat.

A good place to start is which of your windows catch the afternoon sun, and what currently stands between that sun and your lounge room.

What the El Niño forecast does and does not tell you

The Bureau of Meteorology says El Niño is at near-record levels. Its weekly Niño3.4 reading for the week ending 27 September was +2.72 °C, against an El Niño threshold of +0.80 °C. By our arithmetic, that is about 3.4 times the threshold (2.72 ÷ 0.80). Models forecast further warming through spring, likely peaking in late spring or summer and persisting into autumn 2027.

For temperatures, the Bureau's long-range forecast as at 10 September 2026 showed most of Australia likely to have above average temperatures over the coming months. ABC News, reporting on this El Niño, notes rainfall typically returns to average by January, "while the effect on temperatures lingers into the new year".

A strong reading is not a promise of a scorching Hunter summer, because the Bureau says a strong El Niño signal "does not necessarily mean strong impacts on Australian rainfall and temperature".

The Bureau also says summer forecasts will become clearer as more information becomes available through spring. The longer trend is steadier: "Climate change is increasing the likelihood of hotter summers and more frequent extreme heat events".

Our view: the forecast leans hot and the detail is not settled. Shading west glass earns its place in any Newcastle summer, El Niño or not.

Why west-facing rooms get so hot on summer afternoons

It comes down to the angle of the sun. On a summer afternoon, the sun meets a west window at an angle of incidence from near 0° up to 30°. That is close to square-on, so the glass presents a large effective area to the sun. By comparison, a north-facing window in summer has a high angle of incidence and can transmit less heat than a west-facing one.

Low sun also slips past the usual defences. Your Home says low-angle east and west sun is "more difficult to shade" than north sun. An eave that keeps the midday sun off a north window does little once the sun drops to just above the neighbour's roof.

Timing makes it worse. Your Home says east-facing glass "can be equally problematic", because heat builds up through the day into the afternoon.

What afternoon glare and the oven effect look like at home

You know the signs. The TV washes out at four o'clock. A stripe of sun bakes one end of the lounge. The timber floor is warm underfoot well after dark.

Insulation alone will not fix it, and can make it worse. Your Home warns that if insulation is installed but the house is not shaded in summer, built-up heat can be kept inside, creating an "oven" effect. Insulation slows heat in both directions. Shade stops the heat arriving in the first place.

There is a balance to strike. Your Home notes that if the visible light transmittance of glass is too low, the room will be too dark, which may lead you to switch on lights and pay more for energy. The aim is to block the sun, not the daylight.

Do plantation shutters keep heat out of west-facing windows?

The honest answer starts outside the house. For east and west elevations, Your Home calls "adjustable vertical shading, such as external blinds" the optimum solution. Shade outside the glass stops the sun before it reaches the window. Your Home lists awnings among the adjustable options.

Inside coverings still have a real role, especially in homes where outside shading is not practical. Your Home says window furnishings (for example, louvres, blinds, curtains) can improve the thermal performance of windows, and are "especially useful to add to existing windows".

Adjustable louvred shutters are an inside window furnishing of the kind Your Home says can improve a window's thermal performance. The louvres tilt, so you can angle them against the afternoon sun and still keep some daylight. And they open fully in winter, in line with Energy.gov.au's advice to open coverings by day when the sun is shining in the cooler months. If you are new to them, our plain-English primer on plantation shutters and the guide to louvre widths cover the basics.

Here is how the other options compare:

• Deep verandas, balconies or pergolas can shade east and west sides but may still admit very low-angle summer sun, so Your Home suggests combining them with planting.
• Vertical louvres or blades, or a pergola with deciduous vines, are the shading Your Home's orientation guide suggests for east and west.
• Window film: Your Home says some films can halve a window's overall SHGC, which can be particularly useful on east and west glass. But it reduces visible light, and a film on glass in direct sun can cause thermal cracking, so Your Home advises an accredited installer.
• Blinds and curtains are the other inside option. Energy.gov.au says coverings work best when they reach the floor, wrap to the wall on each side, and have a light-coloured "block out" backing. Our page on when a blind beats a shutter weighs them up.

Plenty of west-facing rooms end up with a combination: something outside for the worst of the afternoon, something inside for control and privacy. Which mix suits you depends on the window's orientation, what shades it already and how exposed it is. For whole-house advice, Energy.gov.au suggests personalised advice from an energy assessor or building designer. There is more on the energy question in Do Shutters Actually Save Energy?

How to run your coverings on a hot day

The best covering does little if it is open at the wrong time. Energy.gov.au's advice for warmer months is to close coverings during the day to keep the home cool, then open them when the sun sets to let the evening breeze through.

For a west room, the afternoon is the part that matters most. If the louvres are open at 3 pm because nobody is home, the room has soaked up the worst of the day before you walk in.

Flip it in winter: Energy.gov.au says to open them in the day when the sun is shining in cooler months.

When the heat breaks: summer storms

A Hunter summer rarely stays hot and still for long. The NSW SES says El Niño can bring greater weather variability, including damaging winds, large hail and flash flooding. In August, the Bureau told NSW SES that east of the Divide, warmer Tasman Sea temperatures mean coastal troughs and thunderstorms can interrupt the dry spring.

That matters when you choose shading. Outside blinds and awnings need to be retracted when a storm comes through, so check the maker's wind guidance and make retracting them part of your storm routine. Inside coverings do not face the weather, which is one reason homes with exposed west walls often pair the two.

A get-ready checklist before the heat

1. Find your west and east windows. Stand inside at about 4 pm on a sunny day and note which rooms the sun reaches.
2. Protect skylights first. Roof glazing and skylights get almost twice the heat of an unprotected west-facing window of the same area. Your Home suggests external blinds or louvres for them.
3. Watch how your coverings are really used. Are they shut on hot days and opened at sunset, as Energy.gov.au suggests? A covering left open all afternoon is not doing its job.
4. Block the sun, not the daylight. A room made too dark means lights on during the day.
5. Look at what shades the outside already. Deep verandas, balconies or pergolas may still admit very low-angle summer sun late in the day.
6. If you go with film, use an accredited installer, because of the thermal cracking risk on glass in direct sun.

The numbers that matter for your windows

Five figures from government guidance explain why the west window comes first:

• Windows account for up to 87% of a home's heat gain (Your Home) or almost 90% (Energy.gov.au).
• Effective shading can block up to 90% of the heat direct sun puts on a surface.
• A west window on a summer afternoon meets the sun at near 0° up to 30°.
• Window film can halve a window's SHGC, at a cost in daylight.

Your next step

Start with the room that gets the afternoon sun. Note its windows, how they face and what already shades them, then talk it over with Newcastle Shutters. You can book a measure and quote, or if you would rather think it through one room at a time first, start on our Talk It Through page. Our guide to measuring your windows is handy for getting the sizes down before you call.