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New research increases the usability of glazed outdoor living spaces

Glazed balconies and terraces are popular in Finland despite their risk of overheating in the summer. Kimmo Hilliaho’s doctoral dissertation explores the usability of glazed outdoor spaces and the potential to improve their energy efficiency.
Kimmo Hilliaho (33) works as a researcher in the Service Life Engineering of Structures Research Group at TUT’s Laboratory of Civil Engineering.
Kimmo Hilliaho (33) works as a researcher in the Service Life Engineering of Structures Research Group at TUT’s Laboratory of Civil Engineering.

Given the Finnish climate, we usually install glazing solutions to increase the usability of our outdoor living space. Glazing extends the seasonal use of balconies and protects furniture and structures from the natural elements. The downside is the risk of overheating.

“Potential overheating should be considered at the balcony design stage,” says MSc (Tech) Kimmo Hilliaho, who will defend his doctoral dissertation at Tampere University of Technology (TUT) on 18 August.

“Glazing is often both sensible and necessary, but too little attention is paid to the problems of overheating,” Hilliaho says.

Opening the glass panels is easy, but you can end up with outdoor furniture that is covered in pollen and needles. Hilliaho wonders how housing cooperatives routinely overlook the risk of overheating when making decisions about glazing solutions, especially since glazed balconies and terraces are mostly used during the summer in Finland.

“Their focus has been on protection from the elements, perhaps even too much so. User-centred design has taken a back seat.”

Hilliaho emphasizes the importance of designing glazed balconies that are comfortable living areas and whose energy saving potential is reasonably achieved. 

New calculation procedure for architects and designers

As part of his dissertation research, Hilliaho developed a new preliminary calculation procedure for evaluating the heating energy-savings of glazed spaces as well as the mean, maximum and minimum temperature levels during the year. He conducted various temperature and energy efficiency measurements and analysed different glazing solutions.

From an energy saving perspectives, the key is to consider the material and surface properties of the external wall of the building, the amount of solar radiation, and the number of glazed façades when designing glazed outdoor areas. However, increased energy efficiency often translates into higher temperatures in the summer. Hilliaho’s calculation procedure supports the optimization of energy efficiency and, among others, indicates just how high temperatures can climb without sun protection.

“One of the advantages of the calculation procedure is that it helps architects and designers make sure that sun protection and potential energy savings are given due consideration at the design stage,” says Hiiliaho.

“Good design can ensure that glazed balconies and terraces are both comfortable and energy efficient.” 

Glazed balconies can be fitted with sun protection curtains, if passive options are not enough to keep the balcony cool during the summer months. This allow greater user control, as the glass panels and curtains can be freely opened and closed. In addition, the research results have the potential to propel R&D activities in the field.

Public defence of a doctoral dissertation on 18 August 2017

The doctoral dissertation of Master of Science (Technology) Kimmo Hilliaho in the field of construction engineering titled ´Energy Saving Potential and Interior Temperatures of Glazed Spaces:  Evaluation through Measurements and Simulations’ will be publicly examined in the Faculty of Business and Built Environment at Tampere University of Technology (TUT) in room RG202 in the Rakennustalo building (address: Korkeakoulunkatu 5, Tampere, Finland) on Friday, 18 August 2017 at 12:00. 

The opponent will be Research Professor Miimu Airaksinen (VTT Technical Research Centre of Finland). Professor Matti Pentti of Tampere University of Technology will act as Chairman. The public defence will be conducted in Finnish.

The dissertation is available online at:

Further information: Kimmo Hilliaho, tel. +358 40 078 090,


News submitted by: Anna Naukkarinen
Keywords: science and research, image and communications