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


Elisabete’s View

Elisabete and her daughter

We’re here with Elisabete who lives next door to Catherine in Gressel Lane and also had her home retrofitted. Today we are going to ask her how she thought the process went.

Beattie Passive: Good morning Elisabete, how are you today?

Elisabete: I’m good thank you!

Beattie Passive: What was your perception of your home before the retrofit?

Elisabete: Well, before the retrofit my house was cold all the time, even with the heating on! We did not feel comfortable living here in the Winter at all.

Beattie Passive: So, after the retrofit, did your perception change?

Elisabete: Most definitely! We have a great atmosphere in the house now and we don’t need to have the heating on unless it is very cold outside.

Beattie Passive: How would you rate the overall performance of the house now, including comfort and energy use?

Elisabete: The overall performance of the house now is excellent! The house is really warm now and we don’t hear the planes anymore, even though we are under a flight path. We sleep well and are very comfortable. With the MVHR we have fresh air all the time with no mould or bad smells. I can’t ask for more!

Beattie Passive: As the Retrofit was completed while you were still living in the house, how did you find it?

Elisabete: I felt very comfortable. I didn’t have to move out and the workmen didn’t disrupt me much at all.

Beattie Passive: What was the best thing about the project?

Elisabete: Having a warm house and reduced energy bills for sure! Energy is now not lost from the building and I have started to save money already which is very important to us. Also, the fact we basically have a new house with new triple glazed windows, new door new roof and new walls. There are many good things that have happened to us. Thank you for giving us this opportunity. There are so many changes for the better.

Beattie Passive: How about the worst thing?

Elisabete: Nothing! Only little minor things like dust and noise, but what building project doesn’t have that?

Beattie Passive: Are there any matters you wish to tell us about?

Elisabete: I don’t have any problems. Thank you so much for letting me be part of your project. I am so grateful for everything that has been done. I’m so happy to live here now.

Beattie Passive: Thank you for your time Elisabete, we’re glad that you love your new home and hope you enjoy it for years to come.

Elisabete: You’re most welcome.



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Catherine’s Retrofit

We’re here with Catherine who lives in one of the homes that we retrofitted in Gressel Lane, Birmingham. Today we are going to ask her how she thought the process went.


Catherine’s home before (left) and after the retrofit

Beattie Passive: Good morning Catherine how are you today?

Catherine: Yes, I’m fine thanks.

Beattie Passive: Great! Let’s get into some questions.

Beattie Passive: What was your perception of your home before the retrofit?

Catherine: We used to use the heating a lot and were very cold. The heating didn’t stay in the house for long and we often ended up in the living room with loads of blankets to keep warm.

Beattie Passive: So after the retrofit, did your perception change?

Catherine: We don’t use much heating at all now. The rooms stay warm for much longer. We used to have to top up the gas all the time. Now we don’t. We are much happier living here now.

Beattie Passive: How would you rate the overall performance of the house now, including comfort and energy use?

Catherine: Before the retrofit every room in the house was a different temperature. Now, they are all the same and we have a nice temperature throughout.

Beattie Passive: As the Retrofit was completed while you were still living in the houses, how did you find it?

Catherine: Yes, it was alright. The workmen were always nice and friendly and kept me up to date with what was happening.
Works being done
The works are undertaken with little disruption to the residents

Beattie Passive: What was the best thing about the project?

Catherine: I think the best thing is that the house looks nicer on the outside and it is warmer.

Beattie Passive: How about the worst thing?

Catherine: Nothing at all!

Beattie Passive: Are there any matters you wish to tell us about?

Catherine: No problems whatsoever!

Beattie Passive: Thank you for your time Catherine, we’re glad that you love your new home.

Catherine: Happy to help! People need to know how good this system is.



January Event

We held a Retrofit Event in January to provide interested parties with the opportunity to understand more about the Retrofit system. The event started with presentations from Ron Beattie, Managing Director at Beattie Passive and Lubo Jankovic professor from Birmingham City University. Ron Beattie’s presentation provided an overview of the Beattie Passive Retrofit System and its benefits. Lubo Jankovic, who was involved with the project from the start, gave a presentation on Building Physics and Monitoring. Visitors where provided with an opportunity to visit both of our latest completed Retrofit projects a block of six flats in Grandy’s Croft in Solihull and 2 semi-detached homes in Gressel Lane in Birmingham. The event was well attended by over 50 people including those from Housing Associations, Consultants, and Academia.

We hope to hold more events like this soon so you too can come along and see the merits of retrofit.





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From a House to a Home

February 2017

Hello, its Elisabete!

Well, so much had happened since I last posted.

As I mentioned in my last post, after the walls and roof were craned into place they were fixed to the building and all the panels were joined to ensure robust air tightness. After that the team craned in a single storey extension which would be my new utility room – it will be so nice to have a dry, warm room in replacement of the freezing, very damp outbuilding that was their previously. It will make such a difference as a usable space. The Beattie Passive team built these units completely off site at their factory in Norfolk, so it all came in one big piece – it was quite impressive watching it being positioned into place.


Next, they started the job of retiling the roof. They also fitted a rain screen to the houses to protect them. This was attached by fixing battens to the wall and then the screen was attached.



The build team then tided and made good the outside of the houses, it’s almost like our old houses were never here, and I now have a lovely new home.

After the walls and everything was done, a team came in to do an air tightness test and air quality test. Both of the tests came back with excellent results that I am thrilled with. I am happy to bring my daughter up in a home like this.

To top it all off my energy bills are so much cheaper now I can afford to do things I was unable to do before.


Thank you so much Beattie Passive! I love my new home.




Insulating the panels onsite and airtightness

After, the team installed the roof and wall panels, they started to insert the Eco-beads which are little insulated beads that are locked into tightly packed honeycomb matrix with a water based adhesive. The job of the beads is that they make our homes warm and comfortable to live in.  By insulating on site one the panels have been put into position, means that these can easily flow all around the new frame and means there are no gaps or joints where heat can escape.



The team fitted airtightness tape around the new windows and doors and penetrations, it is aluminium foil tape providing a vapour seal join. Next, the Wraptite Membrane was sealed onto the insulated panels; it is a barrier that stops unwanted ventilation heat loss. After all jobs were done the team cleared the whole area outside the building.


The week began with team placing timber battens outside the homes onto the wall panels, they are strips of wood (but could be made of other materials such as: metal, plastic or fiberglass,) that are used to fix siding materials such as tile or shingles. The team then, fixed plastic skirting onto the bottom of the wall panels. Finally, they put in the roof tiles which are to block rain and are made from terracotta or slate.

Over the past couple weeks, (while this was happening) the process did not cause any distractions or disruptions. During this time the site manager informed us about the progress of the project, it is all going very smoothly.

Erecting the TCosy panels

The team begun by taking down the old porch which they will replace with the new one.  They drilled into the wall to create holes for the Mechanical Ventilation and Heat Recovery system which will help to create a good indoor air quality and a comfortable draught free environment. Following this the Beattie Passive team erected the steel frame which will help to support the new roof and walls panels. During this work, the site manager informed both of us about the work and the progress. He explained to us what they are going to do and kept us updated about the work each day.


MVHR Holes Drilled

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Steel Frame Erected

After drilling the walls for both houses the team stripped down the roof and installed new timber frames which will support the TCosy panels. As the week neared to the end, we can see the project has moved forward a lot, all the external building area has been tied up and there is no disruption.

img_8547 img_8543

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img_8571 img_8572

As the work progressed and the TCosy panels and crane arrived on the site, the team continued working so hard with the preparation of how they will install the panels. They removed all the old windows for both houses which will be replaced with new triple glazed windows. During every step of the installation, they keep us and the neighbors informed about the noise and any disruption. The team installed all Beattie Passive wall panels which came together with triple glazed windows.

At this point, we are so happy because the project is moving forward quickly and we are delighted to be part of it.

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Retrofit Plus Insights by Prof Lubo Jankovic, Birmingham City University


Retrofit Plus project transforms existing poorly performing buildings into Passivhaus standard buildings. The retrofit is carried out by Beattie Passive using their TCosy system. BCU are providing research for this project to assist the design team with the retrofit strategy.

At the start of the project the objective was to go for full zero carbon retrofit. Half way through the project a national scheme called Green Deal was discontinued and the funding for renewable energy in Retrofit Plus disappeared as result. Our revised objective was to put the buildings to be retrofitted onto a trajectory to zero carbon so that full zero carbon performance can be achieved at a later date.

The buildings to be retrofitted were provided to the project by Birmingham City Council (Figure 1).


Figure 1 Two semi-detached houses to be retrofitted

Establishing pre-retrofit base case

 A 3D laser scan was carried out by the University, in order to create a model that can be used for off-site measurements by the project lead industrial partner Beattie Passive, in order to manufacture the retrofit system in their factory. Eight different laser scans were taken, one high resolution and one low resolution from each of the corners of the buildings, and the scans were ‘stitched-up’ to create a unified model (Figure 2).


Figure 2 Unified point cloud from multiple 3D laser scans for off-site analysis and measurements

Subsequently, BCU staff delivered training to Beattie Passive to enable their staff to use the 3D scan for off site measurements. This minimised the travel for Beattie Passive from their base in Norfolk to the retrofit site in Birmingham.

A team of surveyors was brought in to establish details about construction types, such as materials, layers, thicknesses, condition of the constructions etc. The buildings were identified as Wimpey No-Fines type, characterised with concrete construction – concrete without the sand fraction. This building type was constructed with concrete cast in situ and was not fitted with any thermal insulation. Over 300,000 buildings of this type have been constructed in the UK, and most of them require urgent retrofit.

A number of thermal images of the building were taken, and these corroborate the absence of thermal insulation in walls (figure 3). Brighter colours in this Figure indicate areas of high heat loss to the outside that coincide with the internal positions of central heating radiators.


Figure 3 Thermal image of the building with bright colours indicating high heat losses from central heating radiators

As result of the high heat losses identified through the survey, building occupants spend more energy to keep warm. Even with higher energy bills it is harder to be comfortable in a house where most of the heat disappears through un-insulated walls.

A University PhD student carried out a detailed internal survey in order to create CAD drawings of the building.  These helped to create a series of computer models that will be used for design analysis (Figure 4).


Figure 4 computer model development from IES Virtual Environment (top left) via DesignBuilder (top right) to EnergyPlus (bottom right) and JEPus+EA (bottom left)

This computer modeling path was chosen to enable initial student input in IES VE to be transferred to a modeling tool capable of calibration and design optimization (JEPlus+EA).

Finally, the computer model of the building was calibrated with gas and electricity data obtained from the house occupants for the past two years. The results of the calibration determined the parameters of the model that resulted in the minimum error between computer simulated energy consumption and actual energy consumption recorded in the energy bills. The errors of the calibrated model were 0.17% in respect of electricity consumption and 0.33% in respect of gas consumption, meaning that the model was 99.83% accurate in respect of electricity consumption and 99.67% accurate in respect of gas consumption.

The model calibration was the final stage of establishing the pre-retrofit base case, and it resulted in an accurate computer model for design analysis.

Design analysis

The pre-retrofit base case in the previous step created an accurate computer model that can be ‘pushed and poked’ to see what happens with different design interventions. Unlike the most of design projects in which up to half a dozen model variations are investigated, we adopted a multi-objective approach in which several thousand design options were to be investigated.

The technical parameters for optimisation were:

  • three different thicknesses of TCosy wall insulation: 150mm, 200mm and 225mm, combined in pairs with the identical TCosy roof insulation thicknesses;
  • infiltration air changes per hour;
  • fuel type (gas or biomass);
  • lighting power density; and
  • two different PV arrays (East side of the roof only, and East and West side combined).

The user behaviour parameters for optimisation were:

  • room set temperature and
  • clothing level.

The objectives of the optimisation analysis were to minimise CO2 emissions and maximise thermal comfort. A total of 4860 simulation cases were investigated in order to select a subset of best cases to be considered for final design.

The results of design analysis are shown in Figure 5, where a trajectory from a minimum intervention to zero carbon retrofit is plotted using the results of individual design simulations.


Figure 5 Trajectory to zero carbon

The trajectory in Figure 5 starts with a minimum intervention in point 1: 150mm wall and roof insulation TCosy system is added, whilst using the existing gas boiler, keeping the infiltration rate high, and without adding any PV. The resultant room set temperature is low (16 oC); the level of occupant clothing is high (1.4 clo), indicating the use of clothing levels higher than woolly pullovers; and carbon emissions are high: 2,565 kgCO2 per year. As we progress from point 1 via point 2 to point 3, which is based on TCosy 225mm insulation, the room set temperature increases to 21oC, the clothing level reduces to 0.8 clo (a shirt instead of a pullover) and carbon emissions are reduced to -336 kgCO2 per year with the application of renewable energy. The overall reduction of energy consumption is estimated to be significant, well over 80%.

These results indicate that deep retrofit does not only result in energy consumption reduction and carbon emission reduction, but it also creates opportunities for improvements of occupants’ wellbeing.

Prof Lubo Jankovic, Birmingham City University

Preparation for Retrofit Panels

As ground work is nearing the end, the team started with finishing the drainage work for Catherine’s house, they installed new pipes for her kitchen and toilet and are moving the old drainage for a new one.

They also finished preparing the external area for both houses where they dug trenches and built the foundations where new outhouses will be. At the end, they cleared the remaining rubble and kept the slabs which they removed from front parking at the safe place. Foundation Brackets have been fixed to our houses these will be used to fix the new panels to the wall.

The project is moving forward and the new Beattie Passive team has arrived, they are very polite to both of us. The explained to us about what are they going to do and keep us informed about the work. They started by installing plastic lining membrane to the outbuildings wall which will help to prevent the damp for both houses. Also, Scaffolding has been installed to the whole outside building to support and help the builders and their work.  At the end of this week all the ground work has been done and we are very happy because most of the structure work has been done for outbuildings and there are not any disruptions.










Foundations and trenches

As the ground work continue, the team started with finishing the drainage work for my house, they installed new pipes for both kitchen and toilet. Also, they prepared Catherine’s external area and dug trenches around her external building as well as moving the old drainage for a new one where the TCosy will be.

Both of our outbuildings have been prepared ready for foundation and all the rubbles been cleared too and very safe to go in and out.

I found this week not difficult for both of us, as we are very happy because most of work has been done outside the house and doesn’t affect us, no dust inside our home and we hardly hear any noise.

To be honest, we are delighted as the project is moving forward very fast and soon everything will be done.