Renewable and zero direct emissions heating systems in affordable housing projects (phase 2): evaluation

An evaluation of the selection, installation and performance of zero direct emissions heating (ZDEH) systems installed in new affordable homes in Scotland.

5. WP3 – Case studies

5.1. Stakeholder opinion on case studies

5.1.1. Rationale

Across WP1 and WP2, the stakeholders were very supportive of case studies being developed as a resource for the knowledge sharing hub, with key reasons for support including:

  • To guide developers on what heating systems and specifications are appropriate for different housing types and locations.
  • To provide evidence of the operational costs of various ZDEH systems.
  • To demonstrate the successes and challenges associated with developing and operating ZDEH systems.
  • To give Council/RSL developers peace of mind that a given heating system is a good solution for tenants.
  • To provide more training materials for staff.
  • To help educate tenants on comfortable and cost-effective heating system operation.

5.1.2. Content

Among the stakeholders, there was a strong feeling that case studies should present unbiased, evidence-based information that is replicable for as broad as possible a range of development types, sizes and locations.

In terms of the content of case studies, stakeholders made the following suggestions:

  • Examples of systems that have worked well in practice, including systems that have been designed, installed, and maintained well.
  • Projects that are replicable (i.e., not innovation or grant-funded projects that cannot be achieved within typical budgets).
  • The names of reliable contractors and manufacturers.
  • Details of how the systems were funded.
  • Actual capital and operational costs of ZDEH systems.
  • Effective strategies for educating tenants on how to operate ZDEH systems.
  • Positive and negative experiences, and lessons learned.
  • Contact details to allow follow-up conversations with the housebuilder.

"I'd want to see how tenants were impacted, and what went well and badly. The case studies should be honest and highlight lessons learned. I don't want to feel like I'm being sold something."

"Evidence is essential - without this, a case study is just a bit of advertising and a pat on the back for the housing provider."

Whilst support for case studies was high, the following reservations were raised:

  • The case studies need to be well advertised so they are not a wasted opportunity.
  • Without evidence of real-world costs and post-completion experiences, the case studies may be regarded as low value.
  • Supply chain conditions, the state of the art in terms of ZDEH technologies, and best practice can change very quickly, so the case study library needs to be kept up to date.

These suggestions were used to develop the case study template that Locogen used to create five case studies (Section 5.3) and to develop recommendations for future contributions to the hub's case study library.

5.2. Best practice guidance

It is important that case studies are informative, well presented and efficiently communicate relevant insights, so that they will be of high value to the Scottish housing sector. Having reviewed a wide variety of case studies on built environment projects, we created a template for the five initial case studies to draw from the best elements of these. Suggestions for layout formatting are listed in the table below.

Table 9: Suggestions for layout and formatting of case studies

What works well

  • Clear layout with headings
  • Use of images and charts
  • Structured narrative points
  • Use of break out boxes
  • Use of quotations
  • Use of relevant data
  • Text broken up by other elements
  • Accessible font sizes

What to avoid

  • Too much continuous text
  • Too many pictures
  • Too much use of color
  • Crowded layout due to lack of blank space
  • Sales and marketing narrative

Suggestions for case study content, along with the rationale for each of these, are provided in the table below. These are based on the findings from the previous work packages and are believed to help the reader determine how they could successfully implement a given ZDEH technology in a new development.

Table 10: Suggestions for content of case studies

Size, unit types and location of development

  • Rationale: To provide context that will help establish the relevancy of the case study to the reader

Name of housing provider and contact details

  • Rationale: To allow the reader to follow up with the provider if they have questions

Details of the heating system (including manufacturer), heat delivery system and in-home controls

  • Rationale: To provide a technical overview of the heating system and its key elements

Explanation of the development process, including funding sources, justification for key decisions made, and details of any problems faced

  • Rationale: To highlight what process was followed, what decisions were made and what challenges were faced prior to handover and how these were addressed

Explanation of handover process

  • Rationale: To demonstrate how the handover process introduced the heating system and its controls to tenants, and any good or bad outcomes

Feedback from occupants

  • Rationale: To provide evidence of tenant/owner perceptions of the heating system, what compliments and complaints they had and what support they required to address these

Actual annual running costs

  • Rationale: To provide evidence of what occupants pay for their heating systems

Technical performance, including long-term efficiency, planned and unplanned maintenance requirements

  • Rationale: To provide evidence on how the heating systems performed compared to expectations, and what issues were faced and how these were resolved

Lessons learned, including the key challenges and successes of the project

  • Rationale: To highlight important insights from all phases of the project, so that the reader can learn from these

From WP1 and WP2, stakeholders highlighted the following questions that they would like case studies to address:

  • What are the actual capital, running and maintenance costs of ZDEH systems?
  • How can air source heat pumps work for developments with flats?
  • How do heat pumps impact disabled tenants?
  • What are all of the ZDEH options, aside from ASHPs?
  • How does billing work for district heating systems?
  • Which manufacturers and contractors can we rely on?
  • Do ASHPs work as well in colder locations?
  • When is a 'fabric first' approach with direct electric heating more cost effective than an ASHP?

Whilst these topics represent some of the sector's current priorities and concerns, it is important to acknowledge that these will change over time, due to changes to innovations in technology and best practice, and changes to policy, regulation and the supply chain. Therefore, if the hub advertises suggested topics to guide the content of case studies, these should be reviewed (annually at a minimum) to ensure that the case studies remain relevant over time.

5.3. Case Studies

Given the strong indication from stakeholders that case studies should detail operational experiences and be supported by numerical data, we approached housing associations with operational projects, where heating cost and/or demand had been monitored for at least a year. The case studies completed are presented in a separate document and summarised in the table below.

Table 11: Overview of completed case studies
Project Housing provider Technology Occupation date Location No. of units
Dunbeg Phase 3 Link Group ASHPs 2021 Argyll and Bute 300
Suisnish Place Lochalsh and Skye Housing Association ASHPs 2018 Highland 24
MacKenzie Avenue Hebridean Housing Partnership ASHPs 2020 Western Isles 7
Kirkton O'Neil Phase 1 Osprey Housing ASHPs 2020 Aberdeenshire 50
Wharton Square Hillcrest Housing Heat network 2013 Edinburgh 174

5.3.1. Suggested future case studies

During the process of selecting potential case studies, the following projects were identified. These are expected to make valuable contributions to the knowledge hub, on the basis that they meet the current questions of the sector, but either were not ready to be profiled at the time of writing or were surplus to the agreed WP3 scope.

Table 12: Summary of proposed case studies

Project: Granton

  • Housing provider: City of Edinburgh Council
  • Technology: Communal ASHP
  • Status: In development
  • Location: Edinburgh

Project: The Blar

  • Housing provider: Highland Council
  • Technology: ASHPs, PV, Heat Batteries
  • Status: In development
  • Location: Highland

Project: Tomintoul

  • Housing provider: Tomintoul and Glenlivet Development Trust
  • Technology: ASHPs, PV, Heat Batteries
  • Status: In development
  • Location: Moray

Project: Queens Quay

  • Housing provider: West Dunbartonshire Council
  • Technology: District heating from River-source heat pump
  • Status: Operational
  • Location: West Dunbartonshire

Project: Newbridge

  • Housing provider: Hillcrest Homes
  • Technology: GSHP
  • Status: In development
  • Location: Edinburgh

Project: Glenrothes

  • Housing provider
  • Kingdom Housing Association
  • Technology: District heating from industrial
  • Status: In development
  • Location: Fife

Project: Galashiels

  • Housing provider: Eildon Housing Association
  • Technology: Communal ASHP
  • Status: In development
  • Location: Scottish Borders

We also approached ZDEH technology manufactures directly to ascertain if they had any existing case studies on Scottish new build housing projects that could be added to the hub. No examples were found, although Kensa advised that they were working on a case study of a GSHP in April 2022, and that they would be happy for this to be included in a prospective knowledge hub. Scotland's Housing Network and the Scottish Federation of Housing Associations both indicated that they would encourage their members to submit case studies to the hub.



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