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Sydney’s Heat Is Rising. Here’s How to Keep Your Home Comfortable

Sydney’s Heat Is Rising. Here’s How to Keep Your Home Comfortable

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Sydneysiders are already feeling the heat, even though summer isn’t fully here yet. And with the festive season approaching, it’s only going to get hotter. Enjoying the sun by the harbour sounds perfect – just not when that heat gets trapped inside your home, making it uncomfortably warm all summer. From west-facing glass in the inner west to humid sea breezes in the east, Sydney’s microclimates can turn living rooms into heat sinks and bedrooms into ovens. The good news: you don’t need a full renovation to make a real difference. With a smart mix of shading, ventilation, sealing and window upgrades, you can keep indoor temperature steadier and your energy bills saner.

Below is a practical guide tailored to Sydney homes – terraces, apartments and family houses alike.

Why Sydney Homes Overheat

Low-angle western sun
From about 2pm, the sun hits west-facing windows at a harsh angle. Large panes act like solar collectors, soaking up heat that lingers into the evening.

Urban heat island
Dense streetscapes store heat. Brick, concrete and dark roofs re-radiate warmth after sunset, so homes cool more slowly.

Humidity + sea breezes
Onshore winds can feel cooling outside but humid air makes interiors muggy and slow to shed heat.

Mixed building stock
Terraces with single glazing and minimal eaves, mid-rise apartments with big sliders and older fibro or brick homes often lack effective shading and insulation.

Step 1: Stop Heat Before It Hits the Window

External shading does the heavy lifting. Blocking sun outside is the most effective way to reduce heat gain.

  • Awnings or external blinds: Ideal for west and north elevations. Retractable options let you adapt through the seasons.
  • Fixed shade: Eaves, pergolas, or shade sails on patios and balconies.
  • Vegetation: Deciduous vines or trees shade in summer, allow winter sun in.
  • Screens: Perforated or louvered screens provide shade while preserving airflow and views.

Tip: Prioritise the largest west-facing panes first. That one improvement often delivers the biggest comfort jump.

Step 2: Use Window Films to Cut Glare and Radiant Heat

Even with shading, some sun gets through. Solar control window film (like Magnetite’s Solartite) helps by reducing solar heat gain and glare while blocking UV that fades floors and furniture. It’s a low-disruption upgrade for harsh exposures, especially in apartments where external shading isn’t possible.

  • Choose films with high visible light transmission if you want a clear look.
  • Target west and north glass, and any glass that reflects heat back into bedrooms at night.

Step 3: Seal the Leaks that Undermine Cooling

Hot air sneaks in through gaps around sashes, sliders and doors. Sealing is simple and cost-effective.

  • Weather seals: Fit compression or brush seals on operable windows and doors.
  • Door sweeps: Stop warm air and dust at the threshold.
  • Small penetrations: Letterboxes, exhausts, pet doors – add covers or baffles to reduce leakage.

You’ll feel fewer draughts, your AC won’t work as hard and rooms will hold temperature longer into the evening.

Step 4: Upgrade the Glass Without Replacing Windows

Single panes windows transmit heat and then radiate it back into the room. Double glazing windows adds a second barrier that slowing downg the heat transfer. You can do this two ways:

Full replacement
New frames with insulated glass units. Best for comprehensive renovations but more costly and disruptive.

Retrofit double glazing windows
A secondary panel fitted to the inside of your existing window sill, creating a sealed air gap. It’s faster, often more affordable, strata-friendly and ideal for terraces and apartments where external changes are limited. Besides heat, retrofit double glazing window systems help with unwanted external noise (traffic, aircraft, entertainment precincts).Balanced take: External shading blocks the most heat; a double glazing window reduces what remains and stops the glass from radiating warmth into your room later. Together they work brilliantly in Sydney.

Step 5: Ventilate With Intention (Not Randomly)

Ventilation helps – when timed right.

  • Night purging: On cooler nights, open windows on opposite sides to flush out warm air. Close up in the morning before temps climb.
  • Stack effect: If you have upper windows or a stairwell, crack a high window to let hot air escape.
  • Filter smoky days: On bushfire smoke or poor AQI days, keep windows shut, run air purifiers and rely on sealed envelopes and efficient cooling.

Step 6: Tune the Inside to Reduce Heat Stress

Little changes add up.

  • Curtains with thermal lining: They cut radiant heat from the glass and help in winter too.
  • Rugs with dense underlay: Reduce echo and a bit of heat reflection on hard floors.
  • Ceiling fans: Set to summer mode (counter-clockwise) to create a gentle breeze that improves perceived comfort.
  • Light colours: Interior blinds and curtains in lighter tones reflect heat better than dark fabrics.

Room-by-Room Priorities for Sydney

West-facing bedrooms
External shade if possible. Add solar film and lined curtains. Retrofit double glazing if the room holds heat into the night.

Living rooms with big sliders
Shade first. Seal tracks and frames. Consider film and retrofit glazing to stabilise temps and improve acoustic comfort during evening traffic or weekend events.

Home offices
Reduce afternoon glare and heat with film and blinds. Seal the window and door. Double glazing helps if your office faces a busy street.

Terraces and heritage homes
Retrofit solutions are discreet and usually avoid façade changes. Combine internal upgrades with clever shading in courtyards or light wells.

What Results Can You Expect?

Every home is different, but homeowners typically report:

  • Lower afternoon peaks in west-facing rooms
  • Less overnight stuffiness as glass radiates less heat back into the space
  • Shorter AC run times to hold set temperatures
  • Quieter interiors as a useful side effect of better glazing and sealing
  • Reduced fading thanks to UV control from films and curtains

The aim isn’t to turn your home into a fridge. It’s to flatten the spikes so your place feels steady and comfortable through the hottest hours.

A Simple Sydney Plan You Can Phase In

This week
Add lined curtains. Seal obvious gaps. Use day-night blinds to manage glare without losing all the light.

This month
Install external shade on the worst window or add solar film where shade isn’t possible. Fit door sweeps to bedrooms.

This season
Retrofit double glazing on priority rooms—west-facing bedrooms and main living areas. Consider ceiling fans if you don’t have them.

Phasing lets you spread costs and feel improvements at each step.

Sydney’s summer heat can be intense but you can prepare your home to beat the heat. Stop heat before it reaches your windows. Reduce what gets through with film. Seal the gaps. Then upgrade the windows for a lasting buffer against heat and noise. The result is a home that feels calmer through late afternoons, cools faster when the change rolls in and costs less to keep comfortable.

If you’d like practical options for your home, ask for a free window assessment with Magnetite Sydney. You’ll get a plan that prioritises the worst rooms first and layers shading, sealing, and glazing for real-world summer comfort.

  1. Conduction
    Heat moving through an object (i.e. heat will travel through an aluminium, or steel frame more easily than through a timber or PVC frame).
  2. Radiant heat
    Heat from the direct sun. It can pass through space until reflected or absorbed.
  3. Convection
    Heat flow resulting from air movement e.g. either 'natural' convection - warm air rises, or 'forced' convection - a breeze by a window, both can result in a draught by a window.
  4. Infiltration
    Air leaks around the frame, around the window sash and through the gaps in the movable window parts.

When evaluating your options to improve the thermal performance of your windows, the following double glazing key performance criteria should be considered:

  • U-Value (Uw) represents heat transfer through a window, irrespective of direct sunlight. The lower a window’s U-Value, the better the insulation performance.
  • Solar Heat Gain Coefficient (SHGC) measures the solar energy that passes through glazing. The lower the SHGC, the less solar heat is transmitted through a window.
  • Air Infiltration or leakage measures the rate at which air passes through gaps in window joins and seals. The lower the air infiltration, the better a window’s energy performance.

The Window Energy Rating Scheme (WERS) Thermal Performance

Aluminium Frame Windows

Glazing Type Cooling Stars Heating Stars Cool% Heat% Uw SHGC
Single glazed 3mm clear glass* half blue star red starhalf red star 7.4 0.77
Single glazed 3mm clear glass &
4.5mm Magnetite		 blue starblue starhalf blue star red starred starred starred starred starhalf red star 35% 59% 2.9 0.67

Timber Frame Windows

Glazing Type Cooling Stars Heating Stars Cool% Heat% Uw SHGC
Single glazed 3mm clear glass* blue starhalf blue star red starred starred starhalf red star 20% 28% 5.5 0.69
Single glazed 3mm clear glass &
4.5mm Magnetite		 blue starblue starhalf blue star red starred starred starred starred starred star 37% 61% 2.6 0.66
Single glazed 3mm clear glass with
Solartite** and 4.5mm Magnetite		 blue starblue starblue starblue starblue starblue starhalf blue star red starred starred starred starhalf red star 76% 45% 1.8 0.20

 

*WERS standard typical industry window
**Solartite is a range of high performance window film. The window tested above has Solartite’s low-e film.

Magnetite vs Traditional Double Glazing – What the experts says

Winter - the ideal situation is to let in as much of the sun's heat and then trap it inside to maintain a comfortable environment in your home or office. This will also significantly reduce heating costs and saves you money. The ideal window for winter will have a high SHGC to let the sun's heat in and a low U-Value to prevent the heat from escaping. Clear windows without shading films are better suited for winter climates.

Compared with traditional double-glazing, Magnetite’s double-glazing solution can provide better results during winter or for cold climate areas such as Canberra, the Adelaide Hills and Blue Mountains.

Magnetite's clear acrylic window panels allow the direct heat from the sun's rays to enter the building and once inside, Magnetite's superior magnetic seals retain the heat, giving Magnetite an advantage over conventional operating windows.

Glazing Type Cooling Stars Heating Stars Cool% Heat% Uw SHGC AI
Double Glazed 3mm clear glass/12mm air
gap/3mm clear glass IGU (Insulated Glass Unit)*		 blue starblue starhalf blue star red starred starred starred starred starhalf red star 40% 55% 3.0 0.61 5.0
Single glazed 3mm clear glass &
4.5mm Magnetite		 blue starblue starhalf blue star red starred starred starred starred starred star 37% 61% 2.6 0.66 0.5

 

*WERS standard typical industry window

Summer - the ideal situation is to minimize the heat coming in from outside and prevent the cool air inside from escaping through the window. This will make your home more comfortable and reduce your air-conditioning costs. The ideal window for summer, or for a large west-facing window, will have a low SHGC to limit the heat from the sun's direct rays, as well as, a low U-Value to prevent the heat in the air outside from moving through the window and warming the cool conditioned air inside. It is better to have a shading film on the first (outer) glass pane to limit the heat that enters the double glazed unit.

The combination of Magnetite retrofit double glazing and Solartite outperforms the traditional insulated glass unit for hot climate. Magnetite fit over an existing window with reflective film will give better summer heat control than a double-glazed window with supertoned glass.

The Magnetite system stops the conduction and convection of heat better than glass windows giving superior results for summer conditions. Combined with a film or a shading device, Magnetite is the ideal solution for the hot Australian conditions.

Glazing Type Cooling Stars Heating Stars Cool% Heat% Uw SHGC AI
Double Glazed 5mm Supertoned glass/6mm
air gap/5mm clear glass IGU (Insulated Glass Unit)*		 blue starblue starblue starhalf blue star red starred starred starred starhalf red star 54% 425% 3.30 0.461 5.0
Single glazed 3mm glass Solartite**
and 4.5mm Magnetite		 blue starblue starblue starblue starblue starhalf blue star red starred starred starred star 73% 38% 2.4 0.19 0.5

 

*WERS standard typical industry window
**Solartite is a range of high performance window film. The window tested above has Solartite’s low-e film.

Click here to view pdf version of Magnetite WERS test result.

Noise Reduction Technical Data and Results

Proven Results

Noise pollution is one the biggest problems faced in the cities today, particularly in a high-density living. Unwanted noise can be responsible for sleep loss and lack of concentration. This can lead to a deterioration of health through increased stress levels, headaches, high blood pressure and loss of hearing.

Noise penetrates windows through leaky seals or vibrations through the window structure. To reduce noise, a window should minimise air infiltration, hold enough weight to limit vibration and allow a large air cavity. This cavity, or air gap, is the key to secondary glazing.

Expert Advice:

CSIRO Research by John Davy shown an air cavity can effectively enhance sound insulation performance. The larger the air cavity the more noise the window system can reduce. Results show a wide air gap of 100-125mm will improve sound insulation by an average of 7dB(A) more than windows with a narrow gap of 8-13mm.

Window or Glass Door Type Total Glass Thickness (mm) Air Cavity Thickness (mm) Sound Insulation (dB)
Single Glaze 3mm 3 0 23
Single Glaze 6mm 6 0 27
Double Glaze Narrow Gap 9-12 8-13 31
Double Glaze Wide Gap 9-12 100-125 38

 

The human ear is less sensitive to low frequency sound. According to a study released by the CSIRO, the human ear needs a change of 3dB to detect a difference in noise levels and the human ear perceives a change of 10dB as a doubling or halving of the noise level.

If you double the thickness of glass in a window the noise level will decrease by 3dB the least amount possible to make a difference. If the glass is laminated there is no perceived difference in noise reduction.

National Acoustic Laboratory Testing:

Working with the principles of noise transfer, Magnetite® and Soundtite are designed for high performance, which is achieved by combining air tight seals with the ability to maximize an air cavity and the flexibility to vary glazing thickness to suit. Magnetite® is excellent at reducing general noise such as busy roads, commuter trains and noisy neighbours. Whereas, Soundtite works well to combat low frequencies noise such as garbage truck, freight trains or airplane during take-off and landing.

Test Code Material Tested Rw* Improvement
ATF 707 (test window) Aluminium sliding window, 3mm float glass with mohair seals 23 N/A
ATF 709 Test window, 100mm air gap and Magnetite System (4.5mm acrylic panel) 35 52%
ATF 1507 Test window, 100mm air gap and Magnetite System (10.0mm acrylic panel) 39 70%
ATF 817 Test window, 100mm air gap and Soundtite (6.38mm laminated glass) 41 78%

 

*The Weighted Sound Reduction Index (Rw) is a measure for sound insulation performance of a single building element such as windows. The higher the Rw rating, the better the sound insulation.