Are Orangeries and Conservatories cold in the winter?

One of the biggest concerns when it comes to glazed home extensions is that they may feel cold this time of the year.

In fact, orangeries can be incredibly warm and welcoming spaces over the winter, and still feel comfortably cool over the summer. But there are several important factors that contribute to their year-round comfort, even in the coldest of winters.

So why do people worry that orangeries or conservatories are cold in the winter? It’s likely down to the poor reputation of old-fashioned glazed rooms, that were unusable for 6 months of the year. But over the last 30 years we’ve seen great advancements in glazing technology and access to superior materials that have enabled garden rooms to be just as warm as any other room in your house – even during the winter.

Orangery or conservatory on a cold winter morning

Some of the reasons why orangeries or conservatories are not cold in winter


It goes without saying, if you want to hold as much heat inside your home as possible, you will need insulation. Orangeries in particular feature dwarf walls, built columns and a flat roof, all of which can be fully insulated and help to reduce warm air from escaping. In addition, high performing weather seals should be used across all doors and windows to prevent the cold air from outside from entering your home.

Thermally efficient windows and doors

With a large portion of an orangery or conservatory being glazed, it’s important to also minimise the heat loss through the glazed panes. That’s where an understanding of U-values comes in. U-values are calculated by finding the sum of thermal resistance, the lower the U-value the better your glass will perform in the winter as the glass allows a low amount of heat transference. The same principles can also be applied during the summer, with less warm air being transferred from the warm air outside, into your home.

Orangery or conservatory on a cold winter morning

Thermally efficient roof lanterns and glazed rooves

Lanterns are brilliant to not only bring in a great deal of natural light, but they are also thermally efficient. We use toughened, argon filled, 4-16-4 units with warm edge spacer bars as standard. What does all that mean exactly? It means that each toughened pane experiences minimal heat loss throughout the winter and each edge of the sealed glazed units are kept apart to prevent cold bridging – a cold bridge is a gap between two insulated parts. This gap is colder than the surrounding areas and can cause a build-up of condensation. Leading to heat loss, mould growth, deterioration of the building, and making orangeries and conservatories feel cold.

Underfloor heating

When there is a large portion of glazing surrounding the room, there may be little opportunity to hang radiators. Which is why in the past, conservatories had poor heating control. Becoming the only room within your home that doesn’t receive the same central heating. Underfloor heating offers a superior solution, not only warming the tiled floor underfoot. But also warming the room evenly in its entirety.

Orangery or conservatory on a cold winter morning

How important are U-values for glass to ensure your orangeries or conservatories are not cold in the winter?

The first thing to note is that not all glazing is tested the same for its thermal performance. Each and every door or window from our orangeries or conservatories are independently tested for their U-value in their entirety. To give the most accurate performance results possible for the whole product. Glazing and frame.

Comparatively some companies prefer to only test the centre pane which can produce misleading results. This is down to how glass transfers heat. The centre of the pane is the most thermally efficient area of the entire glazed unit. Gradually decreasing around the edges where all glass will experience some loss, until you reach the surrounding framework where there will likely be heat loss. If the U-value of a window is only tested on the centre or the glass pane, your windows and doors could experience a great deal more heat loss than you may have expected over the winter.

Once you understand these different methods of measuring the U-values, they can provide a useful tool into judging how well your dream orangery or conservatory will fair over the winter. Under current regulations*, new buildings require a maximum U-value of 1.6 to ensure your home is energy efficient. However, when tested by an independent body, our U-values ranged from 1.4 as standard, to a low as 1.1 for our triple glazing. Ensuring every orangery or conservatory will stay warm and comfortable over the winter months.

*Time of writing 11/01/22

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