How energy efficient is a contemporary conservatory?

Does an energy efficient contemporary conservatory exist?

The stereotypical view of conservatories is that they are too cold in winter and too hot in summer. This is not ideal for homeowners looking for extra living space that they can use all year round.

The thermal properties of a conservatory or similar structure have also recently become even more of a consideration following updated Part L of the building regulations last year. These reflect an increased focus on sustainability and the energy efficiency of a property.

So while this kind of home extension has been popular in the UK for decades, many people have concerns about glass conservatories’ heat loss and heat gain.

But is it true that it’s hard to find an energy efficient conservatory? And, if so, why? More to the point, if you are looking to extend your home, what are the options for a conservatory or some form of glass room with low heat loss and low heat gain?

How energy efficient is a conservatory?

In this article, we’ll show that an energy efficient contemporary conservatory does exist, although it may not be in the form that you’d expect. By clarifying your idea of what a contemporary conservatory is and what you want to use it for, it is possible to find a glazed structure for your home that maintains a consistent temperature and can be used all year round.

What causes glass conservatories’ heat loss and gain?

A conservatory is predominantly a glass structure, with glazed walls and at least three-quarters of the roof made from glass. The frame is typically uPVC, aluminium or wood.

Much of a traditional conservatory’s heat loss is through its roof. For structures that are more than 10 years old, the roof will have very few insulating features. It is likely to be made from double-glazing or polycarbonate, with the latter recognised as having almost no thermal properties.

This means that when it’s cold, the warm air escapes and the cold air enters the room, leaving it too cold. And during the summer, the heat of the sun beating down on the conservatory is transferred inside, leaving it too warm.

Windows also play a key part in how energy efficient a conservatory is. Like the roof, older conservatory windows in particular can contribute to a greater transfer of cold and warm air.

How to make a conservatory energy efficient

Many conservatories rely on air conditioning or multiple radiators to keep them cool in summer and warm in winter. You can also make a conservatory more energy efficient by filling cavity walls and installing thermal blinds.

But this doesn’t solve the real issue of poor insulation in the glazing and in the whole structure of the roof, windows and doors.

For an existing conservatory, the most effective solution to stop heat loss is to replace the polycarbonate or glass roof with a solid roof. This will make it more energy efficient, but the obvious problem with this option is that it reduces the amount of natural light flooding the space - one of the key reasons for having a conservatory in the first place.

Another solution is to upgrade old windows to more energy efficient glazing. Windows and doors are rated for their thermal performance in two ways: U Values and Window Energy Ratings (WER).

The overall U Value (Uw Value) reflects the heat transfer rate through the glass and frame – essentially measuring how effective a window or door is at stopping heat being lost in winter or gained in summer. The lower the U value, the better. Generally speaking, glass with a U value of 1.2 W/m²K or less is considered energy efficient.

WERs, meanwhile, don’t just measure heat loss as U Values do. They also reflect how much solar gain (heat from the sun) there is, and how much air leakage. The best grading for WERs is an A++ and the worst is an E.

Building Regulations can use WERs for replacement windows in existing homes and U Values for new builds. This is because U Values, unlike WERs, measure thermal efficiency. They are not a true like-for-like and we believe U Values are a true value and the best measurement for contemporary conservatories.

However, in reality, it's not as simple as looking at the U Values or WERs of the windows. To ensure your conservatory is truly energy efficient, you need to look at the thermal properties of the whole structure. This is measured in Uw Values, which reflect the overall thermal performance in W/m²K.

Our team can talk you through the details of how we measure the overall Uw Value of our glass extensions. We'll work with you to to ensure your glass extension meets current Building Regulations and your requirements regarding energy efficiency and thermal performance.

How to find an energy efficient conservatory

If you do not have an existing extension and are looking to expand your living space, you may be looking for an energy efficient conservatory. When you start your search, you will come across a range of glazed structures that all look fairly similar but are called by different names. As well as conservatory, there's glass extension, glass room, garden room, wintergarden, orangery and glass box. Although they all look very similar, there are major differences between how they can be used and the level of energy efficiency they offer.

For example, here at Solarlux by Reveal we use the term ‘Wintergarden’ in its original German sense to refer to highly-insulated, double or triple-glazed glass home extensions. These structures are usable all year round, in effect acting like a contemporary conservatory with a high level of energy efficiency. But you may also find the term ‘Wintergarden' used elsewhere for a single-glazed structure that covers your patio. This provides protection from the weather but is not insulated and therefore is unsuitable for year-round use.

So, it’s important to know what to look for. How do you ensure that you are buying the best glazed structure for your needs, not just for energy efficiency but for how you intend to use it?

What to look for in a glass extension

If energy efficiency is important to you, it is likely you are thinking of using your space throughout the year. So the first thing to find out is the level of glazing in the structure. If it has double or triple glazing, it will be much more energy efficient and is likely to offer a comfortable living space all year round. If, however, single-glazing is the only option, your glass structure will be only suitable as a form of weather protection on your patio or garden.

The next thing to consider is how much glass you would like in your home extension. Many people opt for a high proportion of glazing because they love their space flooded with natural light and they also want to enjoy expansive views of their garden. Orangeries and garden rooms usually combine brick or timber elements with windows and glass doors. This can give them a good level of energy efficiency but means there is less natural light. Conservatories, glass rooms, wintergardens and glass extensions, on the other hand, feature a large amount of glass within a frame, with varying levels of thermal performance and energy efficiency.

Another indication of a glass room’s heat loss is whether it needs a door between the main house. If the answer is yes, this means its energy efficiency is not as great as one that doesn’t need that thermal barrier. Conservatories, even contemporary ones that make use of advances in glazing technology, generally require an external door to the main property in order to comply with building regulations. Retaining an external door means that most conservatories will fulfil Part L of the building regulations. If you do not wish to have an external dividing door between your conservatory and your house, you will need to make sure the whole area complies with these regulations.

Energy efficiency in glass extensions

Solarlux Wintergarden glass extensions function like an energy efficient conservatory. They offer all the benefits that people look for in a conservatory, such as lots of natural light and expansive views of the outdoors, combined with a greater thermal performance that would usually only be possible with a bricks and mortar extension.

Our Wintergardens make glass conservatories’ heat loss a thing of the past. They are so thermally efficient that they are able to maintain a comfortable temperature, whatever the weather outside. A Wintergarden glass extension is not too cold in winter and neither is it too hot in summer.

These glass structures combine double or triple glazing with cutting-edge thermal break technology for optimal insulation and climate control. Additional features can reduce heat transfer even further, including solar glass, ventilation and shading options. They also include a choice of sliding or bi-folding doors so you can open up the space and let the air flow through when the weather is nice.

A Solarlux Wintergarden is a one-system structure, so all components are designed to fit together perfectly. This helps to further bolster insulation and energy efficiency because there is no seal degradation or movement of elements, which can allow heat to escape.

In fact, our glass extensions are so well insulated that you don't need a door or even a wall to your home. There is so little heat transfer between the outside and the inside that they can function just like a proper brick extension to your home. You therefore have the option to knock through should you wish to create a seamless flow between your original property and your extension.

They can deliver as low as 0.99 W/m²K overall Uw value, being so energy efficient that they meet passive house standards.