More and more folks in Perth, Bunbury, and southwest WA are picking energy-efficient windows and doors. They’re trying to choose between double glazing and Low-E glass. Low-E glass does a lot of good things like keeping your place warm in winter and cool in summer. It also stops UV rays from damaging your furniture. But it’s not perfect. It has its own set of problems, and it’s good to know them. This way, you can make a smart choice. Let’s dive into the details of these fancy, energy-saving windows.
Key Takeaways
- Low-E glass can reduce natural light transmission, potentially creating a tinted appearance and increased reflectivity.
- The coating on Low-E glass may lead to a grey haze when exposed to direct sunlight.
- Low-E glass can be more expensive than standard uncoated glass, with a higher initial installation cost.
- Improper application of the Low-E coating can diminish the energy-efficiency benefits.
- In colder climates, Low-E glass can reduce valuable solar heat gain if not combined with double glazing for improved heat retention.
What is Low-E Glass?
Low-e glass stands for low-emissivity glass. It has a special, almost invisible coating. This coating stops a lot of heat from escaping a room compared to ordinary glass.
Low Emissivity and Its Meaning
Emissivity shows how well a material releases heat. Materials like metals, that are low in emissivity, can push back radiant heat. Low-e glass, with its metal-based coating, can keep more warm air inside. This means it helps with saving energy in homes and buildings.
The Microscopic Coating on Glass
A super thin layer of metal or metallic oxide makes up the low-e coating. It’s put on the glass surface. This coating lets less heat through, reflecting more warmth back into the room. It helps to keep rooms at the right temperature with less effort.
Reflecting Thermal Energy
With its ability to reflect warmth, low-e glass does a great job. It helps to maintain comfortable temperatures indoors all year round. So, there’s less need to use heaters or air conditioners. That’s why many energy-smart buildings in Australia use this glass.
How Does Low-E Glass Work?
Low-e glass works because of emissivity. This is how well a material can soak up heat and give it back. Glass takes in heat and sends it out again as warmth. But, its emissivity factor sets how much heat it keeps or lets go.
Emissivity and Thermal Energy Absorption
Regular clear glass lets through about 90% of the heat it gets. But low-e glass is different. It can reflect nearly all of it – up to 95%. This smart design is why low-e glass helps keep buildings cosy in winter and cool in summer. It’s great for saving energy too.
Comparing Emissivity Ratings
The less heat glass absorbs and radiates, the better it is at its job. Double-glazed windows with low-e glass can keep as much heat as a U-value of 0.9. This makes them excellent at stopping heat from going in or out. It means you spend less on heating and cooling.
Reflecting Radiant Energy Like Metals
Low-e glass’s special coating is like metals that reflect light. It bounces back heat instead of letting it through. This feature keeps your space well-insulated while allowing natural light in. Low-e glass is a smart choice for saving energy in your building.
Types of Low-E Glass Coatings
Low-e glass comes in two main types. One is passive low-e, the other is solar control low-e. Each type serves a different purpose. Knowing the differences helps people choose the right one for their home or building, based on the weather.
Passive Low-E Coatings
Passive low-e coatings keep the inside warm by reflecting heat back. They have a low emissivity, sometimes as low as 0.05. This lets them block up to 95% of the heat that tries to escape. They’re great in cold places, helping save on heating bills.
Solar Control Low-E Coatings
Solar control low-e coatings do the opposite. They keep spaces cool by blocking the sun’s heat, while still letting light in. With a higher solar heat gain coefficient, they reflect up to 86% of the sun’s heat. This means you use less air conditioning in the summer. They’re perfect for sunny places that get really hot.
Low-E Glass and UV Light Reduction
When light goes through a window, it includes UV, infrared, and visible light. Low-e glass is designed to stop infrared light but can also cut down on UV light. This glass still lets in plenty of visible light.
Reducing UV Light Transmission
The UV protection of low-e glass is a big win. It keeps your furniture, carpets, and art from fading. By reducing UV light, low-e glass helps maintain your home’s bright and colorful look.
Laminated Glass for Maximum UV Protection
Laminated low-e glass is the best for those needing top UV protection. It has a special layer that adds more UV blocking. This glass blocks almost all UV rays but keeps the energy-saving benefits. It’s a great way to protect your place from the sun’s harm and keep it looking good for longer.
low e glass disadvantages
Low-e glass is great for saving energy, but it does have its downsides. One main issue is less visible light passes through the windows. This can make the inside look darker.
Reduced Visible Light Transmission
Depending on the type, low-e glass can cut light by 25% to 85%. It may look a bit tinted and reflect more light. This affects how the windows look.
Tinted Appearance and Increased Reflectivity
The glass might have a slight tint, which some people don’t like. Also, it reflects more light, especially when the sun shines on it. This is something to think about before choosing it.
Potential for Grey Haze in Direct Sunlight
Sometimes, low-e glass gets a grey haze in bright sunlight. This can affect how the windows look. Homeowners and builders need to know this.
Manufacturing Methods for Low-E Glass
Low-e glass is made using two main methods: hard coat and soft coat. The hard coat method puts a thin layer of tin directly on the glass. This makes the glass strong and scratch-resistant. It’s great for buildings that need tough windows. On the other hand, the soft coat method puts multiple metallic layers on the glass. This makes the glass better at keeping heat inside. It’s often used in homes because it’s more energy efficient. But, it needs to be handled carefully since the coatings are not as strong as hard coat glass.
Both methods have their own perks. Hard coat glass is strong and lasts a long time. Soft coat glass is better at saving energy and is used more in houses. The choice between them depends on what the glass will be used for.
Benefits of Low-E Glass
Low-e glass is great at making your home cosy and saving energy. It keeps the heat inside in winter and blocks too much heat in summer. This means you spend less on heating and cooling your home. It also helps the planet by cutting your home’s carbon footprint.
Improved Insulation and Energy Efficiency
With a low emissivity of just 0.05, low-e glass bounces most heat back into your home. A double-glazed low-e glass unit can have a U-value down to 0.9, showing it’s great at keeping your home warm. When you add other insulation, low-e glass works even better. This makes your home warmer in winter and saves money on heating.
Reduced Overheating from Direct Sunlight
Low-e glass with a low g-value, like 0.14, sends 86% of the sun’s heat back. It stops your home from getting too hot in the sun. This means you won’t need to use the AC as much. It also makes your home or office more comfortable and energy-savvy.
Conclusion
Low-e glass is becoming more popular for energy-efficient buildings. It helps by keeping the heat in or out, depending on the season. Also, it protects against harmful UV rays. But, it’s important to know there are some downsides too.
Putting in low-e glass can be more expensive at first. This might make some people or groups choose not to use it. It also doesn’t come in as many styles. Sometimes, there can be a strange effect on the glass that doesn’t look good, called ghosting.
Even with these challenges, low-e glass is great for saving energy and helping our planet. It will keep getting better as more is learned. This means it will become more affordable and look better. By thinking about both the good and bad points, builders and those making decisions can choose what’s best for our environment and future.
