Why we need to improve thermal comfort in buildings
Warm drowsy meetings, stuffy classrooms, freezing office spaces, cold waiting areas or just a room at home that never seems to feel ‘warm enough’. We all understand the importance of thermal comfort.
And we all understand its impact, particularly following a year where we have spent more time inside than ever before. A lack of thermal comfort makes us feel stressed, annoyed and distracted if it is too cold and it can make us feel sleepy, tired and lacking concentration if it is too hot.
In turn, thermal comfort inevitably has an impact on well-being, productivity, the ability to think clearly and, of course, those around us. When we feel uncomfortable, our mood changes for the worse. More importantly, excessively cold or hot interiors are unhealthy, particularly for the elderly, sick or vulnerable during harsh winters or intense heatwaves.
Impact on productivity and performance
Thermal comfort has wider social implications. To what extent do more thermally comfortable buildings lower hospital admissions, reduce sick days and absenteeism? Improve academic performance? Prevent accidents or improve the productivity of companies?
We know the answers already. We work better, learn better, perform better and feel healthier when we are comfortable.
So, what can we do to improve our thermal well-being? As Knauf Insulation’s Product and Market Manager for the EU & CIS, Benoît Thiry has unique experience of building thermal comfort.
“Our bodies are amazingly sensitive to temperature change and tell us immediately if we are too cold by shivering or sweating when we are hot,” he says. “In simple terms, our thermal comfort depends on the heat balance between our body and the direct environment.”
It sounds straightforward, but it is not.
Thermal comfort is subjective
Firstly, feeling too warm or too hot is highly subjective. You cannot please all the people all the time when it comes to thermal comfort. That is why a mean internationally recognised ‘average of comfort’ is regularly used in calculations (PMV: Predicted Mean Vote).
Secondly, thermal comfort is influenced by six key factors — our metabolic rate (if we are very active or just sitting in one place all day), the clothes we wear (a jumper or just a T-shirt), the ambient air temperature, how fast that air is moving around, the humidity of the air and what is known as radiant temperature — the temperature of surfaces such as walls or windows as well as sources of heat such as the sun or a radiator.
“Radiant temperature has a significant impact on comfort,” says Benoît. “For example, we may feel heat from a radiator on one side of our body while the other side may feel cool if it faces a cold window. That is why radiators are installed close to windows to improve their radiant temperature. If you switch off this radiator, you will quickly feel discomfort if you are close to this cold window even if the air temperature is still the same.”
Why insulation improves thermal comfort
The best long-term solution to ensure overall thermal comfort is insulation. Insulation improves both the ambient temperature and the radiant temperature of surfaces such as external walls, floors and ceilings.
The result? Insulation blocks the path of heat so in winter an insulated home enjoys good thermal comfort due to improved heat retention and improved wall and ceiling surface temperatures. Meanwhile, in summer, the opposite occurs, insulation acts as a barrier to external heat keeping interiors cooler.
“Good insulation in walls, ceilings and floors directly impacts the speed of ambient temperature change inside a building’s envelope,” says Benoît. “Without insulation the tendency is to turn up heating or air-conditioning to compensate for temperature changes which is incredibly wasteful, increases energy bills and has a huge negative environmental impact.”
Good air-tightness is essential
To maximise the performance of insulation it is vital to also have good air-tightness, which means ‘fixing holes’ in the building fabric — such as uninsulated attic junctions or gaps by window frames — where comfortable temperatures can leak out.
It is equally essential to use solutions that allow the building to remain air-tight but also to allow excess humidity to escape this envelope at a pre-defined speed avoiding any risk of condensation. For high humidity rooms, such as your bathroom, an air extractor is also required.
“Insulation is like putting clothing on your building. It creates a protection between us and the external environment which could be cold or hot,” says Benoît. “Compare walking across a wooden floor to a tiled floor early in the morning when it is cold. The difference it clear, the wood acts as insulation compared to the cold tiles and has a direct impact on your comfort, as its surface temperature is higher”
“Now imagine the incredible level of comfort you would feel if high performance Knauf Insulation was installed in your walls, floors and ceiling combined with our air-tightness solutions.”
How Knauf Insulation improves thermal comfort
We have solutions that can be installed externally and internally to improve the thermal comfort of any building type.
We offer products that provide outstanding thermal performance ranging from Rock Mineral Wool and Glass Mineral Wool to Wood Wool and Blowing Wool in addition to our Urbanscape® Green Roof and Wall solutions.
Our solutions also provide A1 fire safety, exceptional acoustic performance and have outstanding eco-credentials. For example, our Glass Mineral Wool with ECOSE Technology® is composed of up to 80% recycled glass and contains no added formaldehyde, artificial dyes or acrylics.
Our solutions can be tailormade to meet any thermal comfort requirements and we have the technical expertise available to find solutions to any building challenge.
Furthermore, we offer accessories such as vapour control layers and weather membranes in addition to tapes and sealants to ensure the highest possible standards of installation.
Here is a selection of some of our solutions:
- Our Glass Mineral Wool solutions for pitched roofs can be laid between joists as well as friction-fitted insulation installed between rafters and even below to ensure a high thickness of insulation.
- Our Rock Mineral Wool insulation solutions for flat roofs offer excellent thermal performance as well as contribute to fire safety thanks to an A1 reaction to fire.
- Our Mineral Wool facades can be easily fixed to building exteriors — providing an advantage of keeping heat in the mass of the walls — while our standard ETICS products are designed for render coating and included in the system of main ETICS system providers.
- Our lightweight ventilated façade systems combined with our Mineral Wool are popular because they are easy and quick to install, and provide a range of aesthetic options for architects and specifiers from wood and PVC claddings to panels or boards of different materials.
- Our Urbanscape® Green Roof solutions can be customised to meet any thermal requirements and are great for biodiversity and absorbing CO2 and air pollution as well as reducing heat island effect when urban areas are hotter than outlying areas.
- Our SUPAFIL Blowing Wool is ideal for new buildings, renovation and for prefabricated buildings with a range of applications for lofts (attics), cavity walls and timber frames.
- Our Heraklith Wood Wool insulation panels — and wool wool finishing panels for walls and ceilings — not only offer a range of different mounting methods but also provide excellent thermal performance due to their wood wool fibre structure and an exciting range of coloured finishes which makes them an attractive addition to any commercial or non-commercial interior.
- Our Homeseal solutions ensure interior comfort by locking in the internal heat of your building , but allow it to breathe, with a specific humidity rate transfer. Our Homeseal accessories are important elements to be installed as they protect insulation from condensation risk and avoid air leaks that lead to a loss of energy.
To learn how Knauf Insulation solutions can help you earn more Green Building Rating System points — including for Thermal comfort — request one of our LEED, BREEAM, DGNB or WELL documents below.
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