How to Keep Your Veranda Cool in Summer

It's one of the most common disappointments we hear from people who've had a veranda or glass room installed by another company. The structure looks exactly as they imagined. The aluminium is clean, the glass is clear, the whole thing is a genuinely attractive addition to the back of the house. And then June arrives. The sun climbs higher in the sky, the days get longer, and the beautiful outdoor room becomes completely unusable by mid-morning. You step into it and the heat hits you like opening an oven door. The furniture is too hot to sit on. Plants wilt. Your dog refuses to go anywhere near it.

This is the greenhouse effect, and it affects verandas and glass rooms far more commonly than most customers are warned about before they buy. At Roma Verandas, we think honesty about this issue is more important than making a sale, so here's a genuinely useful guide to what causes it, how serious it can get, and what the real solutions look like — before and after installation.

Why Glass Structures Get So Hot

The physics involved is straightforward, even if the consequences surprise people. Glass allows short-wave solar radiation — sunlight — to pass through and enter the space. That radiation is absorbed by surfaces inside: the floor, the furniture, the walls. Those surfaces then re-emit heat as longer-wave infrared radiation, which glass does not allow to pass back out as easily. Heat builds up inside the structure faster than it can escape. On a sunny day in July, the temperature inside an unshaded glass room can easily reach 20 to 25 degrees above the ambient outdoor temperature. If it's 25°C outside, your glass room could be 45°C or more inside. That is not a pleasant place to be, and no amount of opening doors will fully compensate.

The extent of the problem depends on several factors: the orientation of the structure, the type of glass used, the roof pitch, whether there are nearby walls or fences that reflect additional heat in, and how much ventilation the structure allows. A south-facing glass room with a shallow roof pitch and no ventilation is about as bad as it gets. An east-facing veranda with a steeper roof, good ventilation, and solar control glass will be significantly more comfortable in summer.

Why Customers Are Often Not Warned

The honest answer is that it's an uncomfortable topic for salespeople who are paid on commission. Telling a customer that their beautiful new glass room will be unusable in summer without additional investment in shading is not a good way to close a sale. The result is that the conversation often doesn't happen, or it happens in a very downplayed way: "you might want to think about adding a blind at some point" rather than "without shading or solar control glass, this space will be too hot to use in summer."

We have spoken to customers who were told by their installer that the blinds were an optional extra for aesthetics, not a functional necessity. They discovered the truth at their own expense. We'd rather have the honest conversation upfront and lose the occasional sale than have a customer spend fifteen to twenty thousand pounds on a structure they can't use for three months of the year.

Solar Control Glass: The Most Effective Upfront Solution

If you are at the planning stage of a veranda or glass room and heat gain in summer is a concern — and for a south or west-facing installation, it should be — the single most effective investment you can make is solar control glass.

Standard float glass has no meaningful ability to reduce heat transmission from solar radiation. Solar control glass incorporates a coating — either a hard coating applied during manufacture or a soft coating applied afterwards — that reflects a significant proportion of solar radiation before it enters the space. A good solar control glass can reduce solar heat gain by 50% or more compared to clear glass, making a dramatic difference to summer comfort.

The trade-off is a modest reduction in visible light transmission. Solar control glass is often slightly tinted — bronze, blue, or neutral grey are common options — and it transmits slightly less daylight than clear glass. For most applications this is barely noticeable, but it's worth understanding before you commit. The performance benefit in summer far outweighs the slight reduction in daylight for the vast majority of homeowners who are using a south or west-facing space.

At Roma Verandas, we discuss glass specification with every customer before installation, including the solar control options available for their particular structure. This is not an upsell — it's information you need to make a good decision.

External Blinds: The Most Effective Retrofit Solution

If your veranda already has standard glass and you're suffering in summer, external blinds are your best option. The reason external blinds are so much more effective than internal ones is fundamental: an internal blind stops light after it has already entered the space and become heat. An external blind prevents the solar radiation from entering in the first place. By the time sunlight has converted to heat inside your glass room, an internal blind is essentially just a warm curtain.

External veranda blinds are available in a range of materials, from open-weave screen fabrics that maintain visibility while cutting solar gain significantly, to denser fabrics that provide near-complete shading. Motorised versions with rain and wind sensors are the most practical for everyday use — they extend when the sun appears and retract automatically if the wind picks up or it starts to rain, without any manual intervention.

The investment in quality external blinds varies depending on the size of the space and the specification, but it is typically significantly less than the cost of the veranda itself — and it transforms the usability of the structure across the whole year.

Ventilation: Essential, Not Optional

Even with solar control glass and external blinds, ventilation remains important. A glass room with no ventilation will always build up heat on a sunny day. Openable sections in the roof — either ridge vents or opening panels — allow hot air to escape at the highest point of the space, where heat naturally accumulates. Side openings, whether sliding glass panels or openable screens, allow cross-ventilation which is significantly more effective at cooling than a single opening.

When specifying a veranda or glass room, we always discuss ventilation as part of the design. It affects the structural specification and the overall cost, but it is not an optional nicety — it is a fundamental part of making a glass structure liveable in summer.

Orientation and Overhangs

If you are at the very early stage of thinking about a veranda and have some flexibility on where it will go, orientation is worth considering. A north-facing veranda will rarely suffer from excessive heat gain — in fact, the challenge is more often the reverse, that it receives limited direct sun. An east-facing structure gets morning sun and is shaded by afternoon, which tends to suit most people well. South and west-facing structures receive the most solar energy and need the most careful specification.

The depth of the veranda roof is also a factor. A deeper overhang shades the glass and the interior more effectively in summer, when the sun is high in the sky, while still allowing low winter sun to reach the space and provide warmth. This is a piece of passive solar design that can be incorporated into the structure itself, at no significant additional cost, during the design stage.

What We'd Say to Anyone Researching Verandas Right Now

If you're currently looking at verandas and comparing quotes from different companies, we'd encourage you to ask each one directly: how does this structure perform in summer, and what is included in this quote to address heat gain? The answer you receive will tell you a lot about how much the installer actually cares about your long-term experience versus closing the sale in front of them.

A company that gives you a straight, detailed answer — including acknowledging that some specification choices will affect summer comfort and explaining how they address that — is a company that has thought carefully about what they're selling you. A company that tells you it won't be a problem, or that you can always add a blind later, may be less focused on your long-term satisfaction.

We're always happy to talk through the specifics of a project, including orientation, glass specification, ventilation, and shading options. Just get in touch.