Tailored comfort

Rory Bergin, Head of Sustainability & Innovation at HTA, the architecture firm commissioned by VELUX to design its CarbonLight Homes, explains how technology can be used to provide energy efficiency and comfort.


The VELUX CarbonLight Homes project involved the design and build of two semi-detached three- and four-bedroom homes in Kettering, in 2011. These homes were designed and constructed to deliver optimum comfort and energy efficiency, and to minimise their impact on the environment. The homes were occupied for a period by guest families who agreed to monitor the homes and be interviewed regularly by the project teams. As a result we now have a much better understanding of what it’s like to live in a sustainable home that constantly tailors itself to the inhabitants’ comfort.

What is comfort?

Comfort means different things to different people, and even different things to the same person depending on their age, state of mind or what they’re wearing. However, control systems usually try to maintain a temperature of between 20˚C and 22˚C, as this is comfortable for most people. But comfort is not a steady state, even though standard automated controls aim for such. Using technology to separate us from the world outside is not the best way to create a comfortable environment. Sometimes a gust of fresh air is just what we need to refresh us, or to wake us up. Sometimes we want to feel the warmth of the sun on our faces, and sometimes this is exactly what we don’t want, as direct sunlight can be an inconvenience if we’re trying to read or work.

But while we notice if the temperature drops or rises dramatically, we are not as good at spotting small changes in our comfort levels. Therefore, tasks like opening the window to let in some fresh air, or turning down the heating, tend to be left until the air is very stuffy, or the temperature uncomfortably high.

Can technology help?

There are some things that technology is great at, such as repetitive tasks that we find boring, or not worth interrupting our daily lives for. What if we were able to leave a lot of these small decisions – these boring tasks – to technology? Would this provide a better level of comfort? Would it free us up to focus on more interesting things? Would we find it disconcerting if windows started opening on their own?

In the VELUX CarbonLight Homes project we investigated this phenomenon and found that technology can do a better job than the home’s inhabitants at maintaining a comfortable environment, provided the technology is well set up. This appears to be related to our inability to notice small differences.

To a computer, a difference is a difference, however small. Whether it’s one degree temperature change or 10, the computer reacts. To us, a difference of a degree is very hard to notice, and there’s a good chance we wouldn’t react at all; by the time we noticed it was too cold, it would be much too cold. The same applies to air quality. In some ways our ability to respond to this is even worse, as poor air quality often makes us sleepy and less capable of responding to further changes. So the longer we are sitting in a stuffy room, the less likely we are to respond to it.

Trusting technology

In one of our VELUX CarbonLight Homes, a couple came back from hospital with their new baby and for a few days were obsessed with managing the temperature in their home, constantly monitoring and adapting the controls. After a while they relaxed, let the system take control and found the results were better than their own efforts. In fact, all the CarbonLight Homes inhabitants very quickly got used to the windows automatically opening to let in fresh air, or blinds closing to cut out glare. After two weeks they generally stopped noticing these things; if they did, it merely served as a reminder of how lucky they were to live in such a clever home!

Bringing light to life

One of the main findings of the study was the effect that daylight has on well-being. Across the project, in different countries, with different types of people, the response was the same: everyone loved living in a home with unusually high levels of natural light. They enjoyed feeling more awake in the morning, they slept better than before, and they didn’t need to turn on the artificial lighting until much later in the day compared to an ‘ordinary’ home. One inhabitant stopped visiting her friends; after living in a CarbonLight Home their houses felt like ‘caves’, so she preferred to invite them round to hers instead!

Homes for today

For a designer of new homes this active comfort management might sound a bit like a ‘Home for the Future’, but in fact this technology is available today. In some respects good quality cars have offered comfort control for decades, but it is only now that good comfort control is available to home owners in a way that requires no interruption to their daily lives.

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