News: Why Is My Conservatory So Hot In Summer

Every conservatory owner suffers the same fate. People get excited when their new conservatory is built and the sun shines for the first time that spring. Fast forward to July, when the same conservatory becomes a room where you can't go past 10 AM without having the fan on full blast. This is one of the most common complaints and, while it might seem complicated to the owner, there is usually a common sense reason for it as they sit in there sweltering trying to read the newspaper.

It's Basically a Greenhouse

The reason isn't complicated, it actually is basically a greenhouse. Glass along with polycarbonate allows sunlight to come through and hit your newly constructed floors and sofas, turning them into heat. That heat is then trapped in the room because it can't escape the same way it got in. On a sunny day, it is not surprising that a conservatory would then be ten degrees hotter than the temperature outside, and in some cases, even more.

The Roof Is Usually the Issue

If your conservatory was built in the 90s or 2000s, there's a good chance it has a polycarbonate roof. They were cost-effective, and many conservatories had them built

Polycarbonate roofs contain some winter cold, but the thin panels are especially bad for passive heat gain. While glass roofs are better for heat gain, they also can struggle when a roof has a small pitch and a poor glazing spec. A solar control coating can also help, but are less effective when the roof has a small pitch.

Ventilation (Or the Lack of It)

To cool down a space, heat has to leave. In many conservatories, heat doesn't leave, because there are fixed windows, small vents, and doors that are usually closed. Roof vents are especially effective, because heat goes to the highest point in the room, and wants to leave up there rather than at the sides. Making air move through the room, rather than just shifting a little near one window, makes a difference greater than many expect.

Which Way Does It Face?

Rooms that face south or west get baked all afternoon and evening. A conservatory that faces north may need very little attention over time. It isn’t anyone’s fault if you experience the worst of the south or west facing afternoon sun, that’s just the nature of where the room sits. However, it will require you more effort to manage, compared to those whose conservatories see no direct sun.

The Walls Underneath

While full-height glazing can be very useful and striking, it can also mean that there is a very large surface area of glass exposed to the sun with no barriers. Conservatories that have a dwarf wall, which means a low wall of brick or block with glazing above, tend to be cooler. This is simply because there is less glass. When it comes to the dilemma of light versus heat, it is a worthwhile trade-off to think about when making decisions.

So What Helps?

There’s no miracle solution—and anyone trying to sell you one probably hasn’t spent time in a conservatory during a heatwave. The best solutions can be a combination of better ventilation, and blinds or films designed to reduce solar gain. The old polycarbonate roofs can be a huge contributor to the issue, and it could be time to look at your options for an upgrade. Opening the windows and doors early in the morning before the heat starts to build, can help a little before the edge of the heat sets in by mid-afternoon.f

A hot conservatory is not an indication of a bad build. Most conservatories were built prioritising light over heat control. Once you understand how your conservatory heats up, it’s easier to decide the priorities for your conservatory, whether it's a few adjustments to how you use the conservatory or a more significant upgrade to the roof and glazing.