Residential project · Planning-stage assessment
A clear comparison for a planning submission.
A residential design team needed evidence comparing a proposed replacement home with the conversion of an existing building. Barlings KWA brought together SAP-based operational-energy calculations and an indicative embodied and whole-life carbon appraisal to assess the options.
The work considered the carbon associated with construction and the energy the homes were modelled to use over the assessment period.
The assessment brief
Account for what each option would provide.
The alternatives would provide different floor areas and numbers of homes. We considered total carbon alongside results per square metre and per dwelling, making those differences clear in the comparison.
SAP-based modelling assessed the proposed fabric, building services and solar PV assumptions. The planning-stage appraisal combined these operational results with embodied-carbon estimates over a 60-year assessment period, using generic carbon factors and stated project assumptions.
What the assessment showed
Understand construction and operational carbon together.
Conversion: lower upfront carbon
Retaining existing material gave the conversion option the lower assessed construction-stage carbon impact.
Replacement home: lower assessed whole-life total
Under the stated assumptions, the proposed replacement home’s lower modelled operational energy produced the lower total over the assessment period.
The result depended on the assessed specification and the different development sizes. The report set out its assumptions and assessment boundaries so the design team and planning officer could understand the comparison.
Outcome for the design team
The carbon-policy query was addressed.
Following submission, the planning officer confirmed that the information addressed the carbon-policy issue raised. The design team had a documented comparison supporting its response.
This was an indicative planning-stage options appraisal using generic factors and stated assumptions. It was scoped separately from standard SAP work and was not a formally assured RICS whole-life carbon assessment.
Planning a similar assessment?
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Send William and Kerry the drawings and the wording of any planning request. We’ll review the information needed and confirm the assessment scope and quotation.
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