The vision of a conservatory is simple: a bright, sun-drenched room offering a year-round connection to the garden. Yet, for many homeowners, that vision gives way to reality once the winter approaches.
As November draws in, the glazed extension becomes the coldest room in the house: a space rarely used between late autumn and early spring.
If you’ve found yourself asking, “Why is my conservatory so cold?”, you will be pleased to discover that the problem isn’t the idea of a glazed room, but often the age and quality of the materials used in its construction.
Understanding where the heat is escaping is the first step to reclaiming your space for comfortable, year-round use.
What are the main causes of a cold conservatory?
A conservatory or orangery is essentially an envelope designed to capture and retain heat. When the structure is cold, it means that the envelope is failing to keep the heat in and the cold out.
The loss of warmth almost always comes down to three key areas: the roof, the glazing, and the frames. Conservatories with wooden frames tend to perform better in winter, as we will explore later.
The outdated roof (the biggest heat thief)
Historically, the conservatory roof was the number one culprit. Thin polycarbonate sheets or old, standard double-glazed glass offered very little insulation, meaning warm air simply conducted through the roof and escaped.
The fix: Modern advancements have dramatically changed this. Options now include high-performance solar-control glass roofs with advanced coatings (low-e coatings) that reflect internal heat back into the room.
Alternatively, a popular and highly effective solution is the solid, insulated roof, such as those used in orangeries, which boast incredibly low U-values (a measure of heat loss) and effectively transform the space into a permanent, thermally regulated extension.
Failing glazing and seals
If your conservatory is over ten or fifteen years old, the double-glazed units may be past their best. Over time, the seals around the glass can fail, allowing the inert gas between the panes to escape. This significantly reduces the glass’s insulating performance.
The fix: Modern conservatories and orangeries are built with high-specification, A-rated double or triple glazing. We ensure our glass units use the latest warm-edge spacer technology and low-emissivity (Low-E) coatings.
This investment acts like a thermal blanket, dramatically limiting heat transfer and keeping cold spots at bay.
Subpar frame materials and air leaks
Even with the best roof and glass, a cold room can be caused by draughts or cold-conducting frames. Older uPVC or aluminum frames, particularly those without effective ‘thermal breaks,’ allow the cold exterior air to travel through the frame material itself, chilling the interior.
The fix: While modern aluminium and uPVC frames have improved, natural timber remains one of the best insulators on the market. High-quality wooden frames have naturally low thermal conductivity, meaning they resist the transfer of cold far better than metal options.
When combined with precision engineering and high-quality seals, a timber frame virtually eliminates cold bridging and drafts, ensuring the space is genuinely integrated with your home’s central heating system.
Orangery vs. conservatory: what’s best for year-round comfort?
When you are planning a new extension, the choice often comes down to an orangery or a conservatory.
While older conservatories earned a reputation as being cold in winter, the reality is that modern, well-designed conservatories using the technology outlined above (performance glass, insulated frames, or solid roofs) are now highly thermally efficient.
The orangery, however, takes thermal performance one step further. By design, an orangery incorporates a solid, insulated roof with a central glazed lantern.
This structure provides a superior balance of natural light and thermal mass, making the room feel like a permanent, cosy extension of the main house and providing excellent insulation on all four seasons.
Reclaim your glazed extension this winter
It’s a common misconception that a glazed extension is an unmanageable space in winter. Whether you choose a classic, contemporary conservatory or a refined timber orangery, the difference lies entirely in the quality of the design and the materials used.
By prioritising high-specification glass, expert installation that eliminates air gaps, and naturally insulating wooden frames, you can ensure your space is not just beautiful, but perfectly comfortable for relaxing, dining, or working from home, all year round.