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What Are Your Options for Energy Efficient Windows? Exploring the Benefits and Drawbacks

Energy Efficient Windows in winter

What Are Your Options for Energy Efficient Windows? Exploring the Benefits and Drawbacks

Energy Efficient windows are becoming increasingly important for home owners as they can help save money on heating costs. When […]

Energy Efficient windows are becoming increasingly important for home owners as they can help save money on heating costs. When upgrading to energy efficient windows there are several options available to you. Each type has its benefits and drawbacks, and in this article, we will take a look at the different types of energy efficient windows, exploring their advantages and disadvantages. From cost savings to improved insulation, energy efficient windows can make a positive impact on your home. Whether you’re looking to reduce your carbon footprint or just save some money on your energy bills, this article will help you decide which type of window is right for you.

What are energy efficient windows?

Energy efficient windows use a number of different materials to reduce energy loss in a home. Energy efficient windows are able to reduce the transfer of heat through the windows, keeping your home warmer in the winter and cooler in the summer. Energy efficient windows can also help reduce the transfer of ultraviolet (UV) rays, protecting your indoor furnishings and reducing your energy bills. The most important factor to consider when selecting energy efficient windows is the type of frame material and the performance of the glass that is used in the windows.

Types of Energy Efficient windows



UPVC or plastic window frames are made from a synthetic material and are the most commonly used in the UK. It is easy to clean, can be made with varying degrees of energy efficiency, and is available in a variety of colours and textures. uPVC has the shortest lifespan, is non-renewable and is generally the least attractive; however, it is also the least expensive option.


Timber window frames are energy efficient, durable, and come in a variety of different styles. The biggest drawback of wood windows is that when cheap timber is used, they require regular maintenance (particularly in climates with heavy rainfall). Using a modern timber such as Accoya®, combined with an effective micro porous paint, will extend the service life of windows to 70 plus years and reduce the amount of maintenance significantly.


Aluminium windows are typically used in commercial buildings, due to their highly modern appearance. Aluminium is a strong and durable material that is resistant to corrosion. The biggest drawback of Aluminium windows is the high upfront cost and the “coldness” of the material. In many cases, this can lead to condensation forming on the frame and potential issues with mould inside a property.

Environmental Impact

One other consideration when choosing which frames to use for your energy efficient windows the impact they have on the environment. Both uPVC and Aluminium frames have a high carbon footprint. The extraction of the raw materials and the manufacturing processes cause a lot of pollution. Timber, on the other hand, can have a negative carbon footprint when it comes from sustainable sources. Check out this study to find out more about the environmental impact of the different sorts of windows frames:


There are many different options when it comes to choosing which glass to use in your energy efficient windows. You will need to use a Low-E or Low Emissivity glass to get the best energy efficiency. Low-E glass allows passive solar heat to enter the building while reflects interior heat back.

The thermal performance of your double glazing is measured by its U-value and solar heat gain coefficient (G value). U-value is the measure of how much heat the double glazing transfers out. If you get glass with a low U-value, it will let out less heat.

How much solar heat the glass allows in is measured by the Solar Heat Gain Coefficient. A high solar value, or g-value, means your double glazing allows more solar heat inside.

There are different treatments that glass can undergo to give it different properties. These properties can be combined, so it’s possible to have thermally efficient, toughened, fire-resistant, laminated, acoustic, self-cleaning, stained glass effect windows!


Insulation in energy efficient windows comes from the cavity between the two panes of glass. Standard double glazing has Argon gas in the cavity. This slows down heat transfer because it is denser than air.

Vacuum Glazing is another option. Instead of filling the cavity with gas, all air is removed. This has two major advantages:

  1. Heat and sound cannot cross a vacuum, so they are thermally and sonically efficient
  2. The cavity can be very, very narrow (0.3mm) and still be as effective as the vastness of space – you can’t have ‘more nothing’.

Suitability for Restoration Projects

The narrow aspect of vacuum glazing makes it ideal for heritage projects where windows are required to look as closely as possible to the original single glazed units that would have been installed in many older buildings. If the property is a Listed building, then it’s a legal requirement to install units that match the originals as closely as possible. This means having double glazing with a very narrow cavity – much like the Vacuum Glazing described earlier. It is possible to get energy efficient windows made from standard double glazing that’s narrowed down. However, these types of windows have serious reliability issues, as we will discuss next.


When standard double glazing is made in an ultra-thin format, the reliability of the units can be compromised. The seals that bond the two panes of glass together around the perimeter can become too thin to withstand even miniscule expansion and contraction due to temperature fluctuations. As a result, these units can have very high failure rates and short lifespans. Some manufacturers of low sightline slim double glazed units are being pursued through the courts for breach of trading standards.

Vacuum glazing, on the other hand, has a mechanical seal which is very resilient, so it can offer many years of trouble-free service. The seal is also impervious to gas, so the cavity remains efficient throughout its service life – compared to the low sightline glass units which slowly lose their cavity gas and become less efficient as a result.

Benefits of energy efficient windows

There are a variety of benefits to energy efficient windows, ranging from cost savings on heating and cooling to improved noise reduction.

Energy efficient windows can reduce the transfer of heat through your windows by up to 40{672140fc81bbf8538617114bced9858b6a0cbab1d6ed15da368cdf22ee20eca7}. This can help to reduce cooling costs in the summer and heating costs in the winter.

In addition, energy efficient windows can reduce the transfer of ultraviolet rays. This can help to protect your indoor furnishings and reduce fading, while also reducing the need for cleaning.

Because Energy efficient windows can improve the overall insulation of a home and help to reduce noise transfer, this makes your home more comfortable. With improved insulation, you should also see a reduction in your energy bills.

Drawbacks of energy efficient windows

While energy efficient windows can come with a variety of benefits, they also come with a few drawbacks. One of the biggest drawbacks of energy efficient windows is that they are more expensive than non-energy efficient windows. This can make energy efficient windows difficult for many homeowners to afford upfront. One of the other drawbacks of energy efficient windows is that they may have a relatively short lifespan if made with ultra slim glazing. This can lead to higher costs in the long-term, as you’ll need to replace your windows more frequently. Energy efficient windows can also have an impact on the aesthetics of a home. While some energy efficient windows can maintain a level of style, others are less visually appealing.

Cost savings of energy efficient windows

Energy efficient windows are often able to reduce your energy bills each month. While this will vary depending on the type of windows you select, you can expect to see quite significant savings. This reduction in energy use can help to lower your overall energy costs each month. You can expect to see the biggest reduction in energy bills in the winter, as windows are the primary source of heat loss in a home. While energy efficient windows will help to reduce your energy bills, it is important to note that they are not a short-term solution. If you are looking for ways to reduce your energy bills in the short-term, you will likely want to explore other options such as installing new insulation, green energy solutions where you produce your own power such as solar panels or heat pumps or switching to a different energy provider.


Energy efficient windows can improve the insulation of your home, reduce your energy bills, and even reduce noise transfer. There are several different types of energy efficient windows, each with its own unique benefits. Energy efficient windows are often more expensive than regular windows, but they can help to reduce energy bills over the long-term. If you are looking to save money on your energy bills, vacuum glazed windows are a great option.