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How To Make Your Windows More Energy Efficient?

Windows More Energy Efficient

How To Make Your Windows More Energy Efficient?

Posted on in Blog

Windows are a major source of heat loss in homes and making them more energy efficient can help to save on energy bills while improving the comfort of your home. In Australia, the average household spends approximately $1,500 on energy bills every year, which can be attributed to inefficient windows. There are several ways that can help to make your windows more energy efficient, and ultimately save you money on your energy bills.

Whether you’re building a new home or looking to upgrade your existing windows, this guide will provide you with the information you need to make informed decisions and save money on your energy bills.

Here are 5 strategies to help you make your windows more energy efficient:

1. Choose Energy-Efficient Windows

Choosing energy-efficient windows is important to ensure your windows do not cost you excessively when it comes to heating or cooling bills.

Energy-efficient windows typically have a lower insulation value (U-value) and the solar heat gain coefficient (SHGC) varies depending on desired summer vs winter performance. This means they are better at keeping the heat in during winter and keeping the heat out during summer.

One way to determine the energy efficiency of a window is to look for the Energy Rating Label (ERL) from the Australian Window Association (AWA). The ERL provides a rating for the window’s overall energy performance, including its U-value and SHGC.

It’s also important to consider the type of window that best suits your needs and climate. For example, if you live in a hot and sunny region, you may want to choose windows with a higher SHGC to keep the heat out. However, if you live in a colder region you may want to choose windows with a lower SHGC to allow the sun in and passively heat the home. By choosing energy-efficient windows, you can reduce your energy costs and improve your home’s comfort.

2. Opt for Low-E coatings

Glass with low-emissivity (Low-E) coatings can help your window to be more energy efficient. Low-E coatings are thin metallic coatings that are applied to the surface of windows to reduce the amount of heat that is transmitted through the glass.

It is particularly effective in areas with high solar radiation as they reduce U-value and reflect a significant amount of solar energy. This can help to keep your home cool during the summer and warm during the winter, without sacrificing natural light. Low-E coatings can also protect your home from UV rays that fade furniture and flooring.

If replacing the glass or window is not an option, you can apply the low-e film to your existing windows which will help to slow the transmission of heat, to keep your home more comfortable during summer. Magnetite’s Solartite range can help improve the performance of your existing glass.

3. Use Window Treatments

Using window treatments such as curtains, blinds and shades are a simple and cost-effective way to make your windows more energy efficient. Thermal curtains or blinds form insulating air pockets that can help to keep warm air inside during the winter, and cool air during the summer. To help you reduce your energy bills and make your home more comfortable, choose materials that are thick and heavy to block out more heat. Floor to ceiling curtains with a pelmet work best to create an insulation barrier around the window.

4. Seal Your Windows

Air leaks account for a significant amount of heat loss/gain in homes. Sealing your windows can help reduce the amount of air that enters or escapes through the window, in turn bringing down your energy costs. Solutions like Magnetite’s Sealtite acoustic and weather seals provide multiple benefits such as soundproofing and windows thermal insulation that can provide comfort year-round.

5. Consider Double Glazing

Double-glazed windows consist of two panes of glass separated by a layer of air or argon gas, which improves insulation and reduces heat transmission. This is particularly effective in areas with extreme temperature variations. Double glazed windows can also reduce noise pollution, improve thermal comfort, and increase the value of your property.

For existing homes, consider retrofit double glazing if replacing your windows is not a feasible option. A secondary glazing system converts your existing window into a double-glazed window without the hassle of replacement. A secondary window system is fitted to the inside of your window reveal, allowing optimum air cavity to meet your requirement whether it is for thermal insulation or soundproofing.

By implementing these strategies, you can reduce your energy consumption and save money on your energy bills all while making your home more comfortable. Before making any changes to your windows, always check with a professional.

Contact Magnetite team today to get a free quote to make your windows more energy efficient.

  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.