Net Zero and Home Energy in Edinburgh: Retrofitting Traditional, Stone-built Tenements and Terraced Houses

3 Jul 2022, Version 1.0

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The need to retrofit our homes to reduce energy consumption and carbon emissions while maintaining (or even improving) domestic comfort is an urgent challenge for individuals and society as a whole. We need action on energy efficiency because the greenest energy is the energy we don’t use

This report gives an overview of the main themes and advice that emerged from a public meeting on Home Energy and Retrofit, 20th June 2022, organised by BANZAI — Bruntsfield Area Net Zero Action Initiative. The meeting was centred on presentations by the following three experts:

Jo McClelland — RIBA (Royal Institute of British Architects) Conservation accredited architect with EALA Impacts, a social enterprise for sustainability in the management of our built environment

Calum Duncan — Calum Duncan Architects, locally-based RIAS (Royal Incorporation of Architects in Scotland) Sustainable Building Design and RIBA (Royal Institute of British Architects) Conservation accredited architect

Cat Magill — Dark Matter Labs, a non-profit collaborating with communities to shape institutions and infrastructure for responding to the climate crisis

We wished to address these key questions:

  • What retrofit measures can individuals take to improve energy efficiency in their homes?
  • Does it make more sense to look at retrofitting groups of properties, for example in a whole tenement, rather than just on an individual level?
  • How might we deal with the social and financial challenges of retrofit and low-carbon energy distribution at a communal level?

More details, including the presentation slides and audio recordings of the speakers, can be found in Home Energy and Retrofit Meeting — a brief update

In line with the meeting’s orientation towards local residents in the Bruntsfield area, we focussed on the challenges of retrofitting traditional, stone-built tenements and terraced houses.

This document consists of three main sections:

  1. The Edinburgh context — the challenge of city-scale retrofit
    This section outlines the scale of the task of decarbonising home energy consumption and provides some pointers about how the City of Edinburgh Council has begun to address this. 
  2. Individual dwellings and buildings
    This is the most detailed section. Just read this if you live in a traditional, stone-built tenement or terraced house and are looking to improve its energy efficiency but aren’t sure what measures to prioritise.
  3. Community action
    This section looks at how groups of residents, in a shared building, a street or even a neighbourhood, can work collaboratively on retrofit and, potentially, apply for funding on a larger scale.

Each of the above sections ends with a short list of resources providing more detailed information if you want to drill deeper. In addition, there is a longer list of resources at the end which gives a broader perspective on the topics covered in the report.

However, if you don’t have time right now to read the whole report, here’s a list of key action points to give you a quick overview.

Key action points

For home-owners

  • The Energy Saving Trust website gives an overview of ways to reduce home heat loss.
  • Make sure to carry out household draught-proofing and insulation of roof spaces first. These measures are relatively simple, cheap and cost-effective.
  • It’s also worth considering secondary glazing, draught-proof insulated shutters and thermal blinds, which can have a significant benefit at a moderate cost.
  • Get expert advice before considering expensive and disruptive work such as double-glazing or wall or under-floor insulation. You need to be sure that the benefit justifies the cost.
  • Properties need to be able to ‘breathe’ to let moisture get out while keeping draughts from getting in. Architects with an interest in retrofit can give good advice, and good guides exist on the best construction techniques to achieve this.
  • It’s better to do a little well than a lot poorly. 
  • Building maintenance, particularly keeping damp out, has a very important part to play in energy efficiency. It’s about as important as draught-proofing and simple insulation. A Building Condition Survey by a qualified surveyor will reveal what needs to be done. Create a maintenance plan which incorporates measures to address energy efficiency over time.
  • If you live in a tenement, setting up an Owners’ Association, or using the Novoville Shared Repairs app (as recommended by the City of Edinburgh Council) can help neighbours to work together.
  • When you think about making any changes, consider the environmental impact of manufacture and supply as well as the direct savings on energy use.
  • From a climate action viewpoint, electricity is better than gas because it can be sourced from renewables. It’s relatively easy to switch to electricity for cooking and showers. However, it is considerably more expensive and you need to take into account the carbon cost of new appliances.

For Communities

  • Join a local street or block community group. It’s good to help develop a sense of community. It should also be useful in future when the authorities get started on community or street-level retrofit work.
  • The City of Edinburgh Council has ambitious Net Zero targets that mean it will almost certainly need to coordinate and support such retrofit at scale in the next few years. Neighbourhoods that have established community groups will be well-placed to benefit.

These points are expanded and put into context in the rest of this document.

The Edinburgh context — the challenge of city-scale retrofit

There are at least 98,000 private homes in Edinburgh. Most of these homes are privately owned and many of them will still form part of the housing stock in 2050. Retrofit at scale will be crucial to meeting the City of Edinburgh Council’s Net Zero 2030 targets; however, the estimated cost of retrofitting them is in the region of £3bn.

The cost of retrofit alongside other critical transitions for Net Zero presents a unique challenge that requires innovative thinking to blend different forms of finance, identify new mechanisms for short- and long-term financing and bring together actors with potential interests in all aspects of retrofit, from homeowners and tradespeople to local authorities, infrastructure developers and investors.

Over the past few years, Dark Matter Labs has been developing a variety of models for initiating, accelerating and financing community-centred retrofit and whole-city transitions. Dark Matter Labs is currently working with the City of Edinburgh Council to develop a programme for retrofitting at the scale of buildings, streets and neighbourhoods. The programme will consider various financing models, including a combination of public and private funding. One possibility would require an upfront capital injection for retrofit by one or more bodies, which would be repaid by beneficiary house owners over a period of years from the savings made in energy consumption.

On a national level, the UK Cities Climate Investment Commission, a partnership between Connected Places Catapult, Core Cities UK, London Councils and other local authorities across the UK, has been exploring the opportunity for private investment in Net Zero initiatives across UK cities. They published their initial findings in October 2021. The second stage of the report is expected later in 2022, outlining the business case for a pilot programme dedicated to testing the place-based approach to Net Zero.

Elements of a neighbourhood-level programme are likely to include a neighbourhood governance model and alignment of retrofit with energy system investment and city investments in Net Zero transition. The Council is investigating and learning from various models of community-based retrofit that are being tried around the country. There is a representative list of Community based retrofit initiatives below.

Support for retrofit at scale may still be some years away. Nevertheless, it makes sense for neighbourhood communities to start thinking now about how to organise themselves. There are many benefits to be gained from neighbourhood-level organisation, and it can take some time to develop. Neighbourhoods that have strong community infrastructure are more resilient in the face of crises and will be well-positioned to prepare for future transitions.

Tenement and terraces — the advantages of shared buildings

Our instincts tend to be that old Victorian stone-built buildings are intrinsically inefficient and hard to retrofit. However, research into heat loss shows that multi-storey blocks of dwellings with shared adjoining walls tend to be significantly more energy-efficient, per household, than the typical existing detached house with more external surface area and so, heat loss. As a result, tenements of the kind typically found in Marchmont and Bruntsfield are an intrinsically efficient way to live with good density and shared party walls.

Yes, our buildings can and should be improved, but we’re already living in a relatively efficient way. Therefore, when it comes to retrofitting, better to do a little, but do it well, than to do a lot poorly, which could cause more problems than it solves.

Individual dwellings and buildings

Fabric first

Make sure you know what needs to be done to get your building up to a decent standard of repair before embarking on retrofit work. 

  • Ideally, get a building conditions survey from a building surveyor (if possible, for the whole building, through an Owners’ Association — see Community action below)
  • If you have any dampness in stonework, fixing that is a priority because a damp wall can be more than 30% less thermally efficient than a dry one (BSI Guide to the Conservation of Historic Buildings, p.12).

Insulation and draught-proofing

Prioritise simpler energy efficiency measures (like draught-proofing) over expensive changes (such as new double-glazing or switching to a heat pump). It’s better to do a little well than a lot which expends carbon and potentially causes damage. Properties need to have a ‘vapour open construction’, so that moisture and water vapour can transfer to the outside. A well-insulated property needs to be air-tight but vapour open. Failure to do this can result in building deterioration from damp, rot and condensation in addition to poor internal air quality. The Pebble Trust Sustainable Renovation Guide advises well on how best to do things to avoid these problems. Get expert property-specific advice when looking at more complex measures.

Basic draught-proofing is relatively simple and very important overall. Consider also how you use your home; for example, you will be more sensitive to draughts in a sitting room or study than in a kitchen where you are moving about and cooking. 

  • Carry out draught-proofing of gaps, for example around doors, windows and pipework, between floorboards and along skirting boards (it’s helpful to get an IR thermal imaging survey, which is something BANZAI hopes to be able to offer in the cooler months).
  • Draught-proof windows with some combination of internal shutters, secondary glazing and thermal blinds. According to Historic Environment Scotland, a single-glazed window with shutters and thermal blinds is more effective in reducing heat loss than a double-glazed window. However, secondary glazing has the advantage that it can also be used during the daytime. Simple forms of near-DIY secondary glazing using clear polycarbonate sheets can be relatively cheap and effective.
  • Well-installed triple-glazed wood frame windows may be a good option where it is not restricted by conservation area or listed building status. Good property-specific advice is needed.

Insulation can be added to roofs, floors and walls:

  • If possible and applicable, insulate the roof space. In a tenement building, this is something that would probably best be handled by setting up an Owners’ Association — see Community action below). The Energy Saving Trust gives an introduction, and extra details can be found in the Pebble Trust guide.
  • Under-floor insulation can be effective for wooden suspended floors, particularly for floors which are located above a void. Depending on what lies underneath, it’s not always necessary to lift the floorboards. The Energy Saving Trust gives an introduction, and extra details can be found in the Pebble Trust guide.
  • Wall insulation is complex and disruptive and the best approach depends on the details of construction. In tenements, it may only be advisable when all flats are insulated at the same time. Good property-specific advice is needed.   

When carrying out more extensive retrofit work, take into account the full ‘carbon cost’ of the changes. It’s tempting to neglect the embodied carbon (the carbon emissions arising from manufacturing and transportation) if we replace something old with something new. Moreover, the affordability of energy efficiency measures doesn’t always align with carbon reduction. For example, the embodied carbon in uPVC windows is far higher than in wooden framed windows and can outweigh the carbon savings made by the reduced heating requirements. 

Heating controls 

As well as reducing draughts, think about where heat is needed and adjust the heating system as appropriate. This can have a major impact on energy consumption at a relatively low cost:

  • Turn the central heating thermostat down. Put on another layer. For living areas, 18℃–19℃ is generally fine, with bedrooms cooler. Many of us have become accustomed to warmer homes than previous generations, but it costs. A 1℃ reduction in temperature can reportedly save up to 10% on energy bills, and doing so across the nation would have a dramatic effect on carbon emissions.
  • The Energy Savings Trust provides an introduction to a wide range of modern heating controls; these include smart thermostats, weather compensation, zone controls and programmable Thermostatic Radiator Valves.

Resources for individual dwellings and buildings

Community action

The Net Zero vision                  

This approach considers the people, buildings and infrastructure within a street as an integrated system for making the transition to a ‘Net Zero Neighbourhood’. This holistic perspective brings together a range of actions:

  • involve residents throughout the whole process
  • retrofit whole buildings, not just individual dwellings
  • provide decentralised low-carbon energy generation
  • incorporate the streetscape, promoting active travel and biodiversity
  • use local skills, support training and encourage neighbourhood entrepreneurs
  • ensure sustainable urban drainage – avoiding property flooding
  • encourage community investment in shared infrastructure assets         

The ABC of resilient communities at a shared building level

For residents in shared buildings to work together on whole-building retrofit, it is important to put into place some structures for governance and decision making. There are three crucial steps (the ABCs):                             

A: Association

If you have shared ownership of a building, set up an Owners’ Association.    

B: Building condition survey                  

Get a Building Condition Survey with a maintenance plan for the next five years, and repeat it every five years. This assumes a Fabric first approach. Work with a suitably qualified Building Surveyor or a qualified Conservation Accredited Architect. There is a recent British Standard (PAS 2035) that is intended to ensure high retrofit standards.         

C: Cash

Set up a Sinking Fund for any outstanding maintenance and future planned maintenance.

Although owners of flats in tenements might feel reluctant to undertake these steps, all of them may soon become compulsory under law, following the recommendations of the Scottish Parliamentary Working Group on Tenement Maintenance. The response by the Scottish Government has been broadly sympathetic to the recommendations; while expressing reservations about the Working Group’s goal of achieving legislation by 2025, they “seek to support voluntary and incremental change” to facilitate the ABC steps above.

Upscaling to street or neighbourhood level               

Typically, shared ownership of Edinburgh tenements is organised by ‘stairs’. However, Owners’ Associations oriented around stairs might not be the best level of granularity for whole-building retrofit and won’t scale up to the vision of Net Zero Neighbourhoods. Nevertheless, they could form a sound basis for a ‘federated’ form of community governance and decision-making — that is, a group of adjacent Owners’ Associations could join together to work at a neighbourhood scale. This in turn offers the prospect of developing one or more neighbourhood ‘Test Projects’ to retrofit a portfolio of similar buildings in conformance with an agreed standard such as EnerPHit.

Resources for Community Action

Under One Roof: Owners’ Associations
“An Owners’ Association is a formal arrangement between the owners of your building. It arranges regular meetings to discuss how your building will be managed and maintained. By ‘formal’ we mean having a constitution — an agreed set of rules and procedures.”

Novoville Shared Repairs phone app
“Novoville was selected by the City of Edinburgh Council to solve the challenge of carrying out the maintenance and repairs of shared areas in housing blocks.” The app supports private owners of a flat in a block (tenement) to proactively take responsibility for planning and organising repairs, and carrying them out following local rules and regulations. It also helps establish a working relationship with companies that can provide a survey/repair plan.

Ethical bank accounts for your Sinking Fund (so the money isn’t supporting climate-damaging industries).

Other Resources for the report as a whole

Sources of expert advice

Building Surveyors:

Conservation Architects:

Community-based retrofit initiatives

Carbon Co-op:
Based in Manchester, this is “an energy services and advocacy cooperative that helps people and communities to make the radical reductions in home carbon emissions necessary to avoid runaway climate change”. 

Cosy Homes Oxfordshire:
“A one-stop home retrofit service, making it simple to make energy efficiency improvements to homes in Oxfordshire.”

Loco Home Retrofit:
A cooperative based in Glasgow, “building a novel community-based approach to home energy decarbonisation. We aim to reduce the hassle of maintaining and improving homes while incorporating energy efficiency and decarbonisation measures.”

People Powered Retrofit: 
“We are a not-for-profit service for householders in Greater Manchester, offering clear, independent advice and support to help you plan, procure and deliver your retrofit project to a high standard.”

“We are owned by community based organisations and local supply chains, to design and host energy efficiency and retrofit schemes.”

More guides to retrofit

The exhibition includes detailed “case-studies of typical Edinburgh buildings, so that visitors can see how their homes, offices and public buildings can be improved to provide a cleaner, healthier, low carbon future. The emphasis is on existing buildings, as these represent the vast majority of carbon emissions…” The exhibition is currently in storage but could be moved around communities in Edinburgh and neighbouring locations. In the interim, there is a Virtual Exhibition of SpACE.

HES: Guide to Energy Retrofit of Traditional Buildings (2021)
“This guide describes retrofit measures which can be used to improve the energy efficiency of traditional buildings, whilst maintaining as much of their historic fabric and creating healthy indoor environments. These measures are backed up by research and showcased in various case studies, as trialled by Historic Environment Scotland. The guide also looks at compatibility with the existing fabric, compliance with building standards and the planning process.”

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