Studies Continue at the Gressel Lane Retrofit

Fig 7.0

The TCosy retrofit in Gressel Lane was completed on 25th January 2017 Instrumental monitoring was in progress already before, and it continued together with occupant studies after the retrofit.

The monitoring system consists of a wireless data logger installed on site, measuring internal temperatures and energy consumption. Wireless sensors send information to the logger once every minute, and the data is then periodically downloaded over the Internet. A scientific weather station located on the roof of the University building provides complementary weather data, measuring external air temperature, relative humidity, horizontal total solar radiation, wind velocity and direction, and rainfall. The instrumental measurements are complemented by data from smart meters installed in each house by two different utility companies.

From this information, energy consumption chart has been created. As it can be seen from this figure, energy consumption after the retrofit is considerably lower than before the retrofit. This needs to be seen in the context of weather data , where external air temperature is generally lower in the winter period after the retrofit, coinciding with very low solar radiation.

Internal temperatures after the retrofit fluctuate much less than before the retrofit, demonstrating that the houses depend less on external conditions, even when external conditions start increasing in the spring.

Fig 8.0
Energy consumption before and after the retrofit


Fig 9.0
Internal room temperatures before and after retrofit
Fig 10.0
Weather data before and after retrofit

You can see that the data shows increased comfort levels in regards to temperature in the rooms, while there is a marked decrease in the gas and electricity usage for both houses.

User experience

The user experience has been very positive. Here are some remarks that the occupants made:

“I did not need heating when outside temperature dropped below freezing yesterday”
“I switched heating on for 20 minutes and it became too hot”
“The house feels like home now – no damp, not dust, no noise.”

Detailed occupant studies are being conducted with periodic questionnaires, and the analysis of results will be released in due course.


These are only initial results, and the work on performance analysis will continue as we gather more data and more information on user experience from the project.


Professor Lubo Jankovic

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