King Street, Great Yarmouth

  • Building Type : Collective housing < 50m
  • Construction Year : 2019
  • Delivery year : 2020
  • Address 1 - street : 89 King Street NR30 2PR GREAT YARMOUTH, United Kingdom
  • Climate zone : [Cfb] Marine Mild Winter, warm summer, no dry season.

  • Net Floor Area : 460 m2
  • Construction/refurbishment cost : 579 750 €
  • Cost/m2 : 1260.33 €/m2

Proposed by :

Certifications :

  • Primary energy need :
    123.6 kWhpe/m2.year
    (Calculation method : Other )
Energy consumption
Economical buildingBuilding
< 50A
51 à 90B
91 à 150C
151 à 230D
231 à 330E
331 à 450F
> 450G
Energy-intensive building

Using our latest innovation in our TCosy retrofit system, Beattie Passive has breathed new life into a 1950s block of flats in Great Yarmouth. By constructing a new super insulated layer around the whole property, eliminating thermal bridges, and installing Heat Recovery Ventilation, we have brought this old inefficient building up to EnerPHit standard - the Passivhaus standard for retrofit. Residents faced limited disturbance, were able to remain at home throughout and are now enjoying much lower energy bills. The building is currently undergoing a performance monitoring period, but we know that we have achieved an excellent airtightness result of 0.67 air changes per hour and a permeability of 0.918 at 50 Pa. We anticipate an 80% reduction in heating demands, greatly decreasing the Carbon footprint of the building, and helping to lift residents out of fuel poverty.

One of the most significant developments of this project was that it proved as a proof of concept of our latest TCosy retrofit system, meaning we now have a highly adaptable and flexible system that can easily retrofit any building in the world to the  EnerPHit standard, providing a very real opportunity to easily and affordibly lift the performance of homes across the world and vastly reduce space heating demand and hence energy usage and carbon emissions.

See more details about this project

Data reliability

3rd part certified

Photo credit

Beattie Passive


    Beattie Passive

    Nathan Beattie, enquiries[a], Norwich, UK

Construction Manager

    Beattie Passive

    Beattie Passive, enquiries[a]


    Environmental consultancy

    Enhabit Ltd

    Sarah Price, norwich[a], Norwich


    Oxford Brookes University

    Rajat Gupta, rgupta[a]

Contracting method

General Contractor

Owner approach of sustainability

This retrofit was carried out on a 1950's style terraced block of of flats in order to lift the thermal performance of the building, reduce its environmental impact and improve the lives of its residents. 

The Beattie Passive build system builds to Passivhaus as standard, and so our goal with this retrofit from the outset was to reach the EnerPHit standard, which we achieved. We have greatly improved the thermal and energy performance of the building, and greatly improved the quality of life for residents. We anticipate the space heating demand to be reduced by up to 80%, reducing the Carbon footprint and saving residents money on their fuel bills. The mould and condensation problems that the property used to face have now also been eliminated, and residents enjoy cleaner air and healthier, more comfortable homes thanks to the Mechanical Ventilation and Heat Recovery.

We have delivered over 400 Passivhaus standard homes across the UK, and this is our 4th large scale Passive retrofit, however the difference with this project is that we were testing a new bracketed system, that if successful could be adapted to fit any building in the world, and with the successful completion of this project in Great Yarmouth, we now have a proven, highly adaptable system that can transform any building in the world into a high performing, Passivhaus standard building.

Architectural description

Often, the design of retrofitted properties are inkeeping with the local surrouding but dont act as a vision of the future - We wanted to create something modern ; high performing and visually stunning that stands out within its environment, to show what could be achieved by doing a deep retrofit to passive standard. 

If you had to do it again?

The fire barrier that we used wasn't particularly easy to install, so going forward we will use an alternative e.g. Rockwall Flexi

Building users opinion

Residents have commented on how much warmer their homes are now, and how much less they use their heating systems, with one resident even being contacted by their energy supplier to enquire about their lower energy use. Residents also note that they no longer experience condensation in their homes and no longer need to use dehumidifiers to remove excess moisture. Additionally, they report that the difference in sound between their homes pre- and post-retrofit is marked and there is now much less noise pollution from the outside in their homes.

Energy consumption

  • 123,60 kWhpe/m2.year
  • 221,40 kWhpe/m2.year
  • Other

  • 221,40 kWhpe/m2.year

Envelope performance

    We injected EPS Superbead insulation into the wall cavity, which creates an insulated barrier around the whole property, including the roof:


  • 0,67


    • Individual gas boiler
    • Gas boiler
    • No cooling system
    • Double flow heat exchanger
    • No renewable energy systems

GHG emissions


Indoor Air quality

    Mechanical Ventilation with Heat Recovery (MVHR) was installed into each flat as part of the retrofit works. This will filter pollen, dust and pollutants out of the air as it enters the property, and also works to remove excess moisture, dust and CO2 from the air inside the property. This continuous supply of fresh, filtered air means residents are always breathing cleaner air, and also helps to alleviate the symptoms of Asthma and other respiratory illnesses.

Health & Comfort

    The excellent insulation and airtightness of the building will now ensure that heat does not escape each resident's home, meaning warmer, more comfortable homes during the colder months, and the aforementioned MVHR also works to regulate indoor temperature to keep it at a regular, comfortable heat during the summer. If too hot, residents can easily open windows or boost their MVHR to release some of the warmer air to help keep them comfortable.



    Beattie Passive

    Beattie Passive, enquiries[a], 01953 687332

    Structural work / Passive system

    Beattie Passive’s TCosyTM is an innovative, whole building approach to large-scale retrofit. It provides a fast, low cost and highly replicable solution for a wide range of buildings. The TCosyTM dramatically reduces energy requirements, creates a healthier living environment and can be delivered whilst residents remain in their homes.Key Benefits of TCosy Retrofit:• Dramatically improve the energy efficiency – up to 75% reduction in heating requirement• A completely new external façade• Increase the value of the property• Resident stays in their home during the Retrofit• A healthier, warmer living environmentUsing our new bracketed approach, we can construct a whole new Structural Thermal Envelope that will reach the EnerPHit standard around any existing property, ensuring that the end result performs highly no matter the building you start with. This particular project is still undergoing performance monitoring until September, but previous TCosy projects have delivered up to 84% reduction in energy bills and an estimated 4 tonnes of CO2 savings annually. We offer TCosy retrofit at approximately £600 per square meter of external surface area.

Construction and exploitation costs

  • 579 750

Urban environment

The King Street retrofit project is situated within a sub-urban neighbourhood of Great Yarmouth, on a relatively quiet two-lane road. There are a few commercial businesses operating along the road, with various parks and recreational spaces within easy walking distance. There are three primary schools in the immediate vicinity, and various dentists/opticians a few minutes walk up the road. A bus stop and a National Express Coach stop are also nearby.

Building Environmental Quality

  • indoor air quality and health
  • acoustics
  • energy efficiency
  • building process

New, super insulated layer built using a thermal-bridge free design and Passivhaus standard windows and doors now encompasses the entire building. We anticipate an 80% reduction in space heating demand as a result, and a corresponding reduction in energy usage. One resident has even reported that their energy supplier has been in touch to enquire about the much lower energy use.

Before the retrofit, each flat has large amounts of mould and damp, with one flat having to use dehumidifiers to clear away residue on their windows each morning, and this has been overcome by the retrofit.

The super insulated, airtight layer also eliminates noise, what used to be considered a noisy estate can now barely be heard from within the building.

Excellent airtightness - 0.67 air changes, n50, and 0.918 permeability at 50 Pa (m3/h/m2).

Residents endured minimal disruption as they were able to remain at home for the complete duration of the works.

Mechanical Ventilation with Heat Recovery has been installed into each flat, preventing loss of heat, and providing a constant stream of fresh air into the property, filtered before it enters the flat to remove pollen, dust and other pollutants. Damp and dust is also efficiently removed by the MVHR, eliminating indoor mould and condensation. This all results in a much more comfortable, healthier environment for residents.

Contest categories

Low Carbon

Low Carbon

Health & Comfort

Health & Comfort

Green Solutions Awards 2020-2021

 energy efficiency
 low carbon
 thermal efficiency
 health and comfort

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    Green Solutions Awards 2020-2021