How we helped Cotswold Homes smash planning requirements with a 60% carbon reduction.
Project Summary
- Project: Engine Common, Yate, South Gloucestershire
- Client: Cotswold Homes
- Service: Sustainability & Energy Statement / SAP Calculations
- Outcome: 59.63% CO₂ Reduction (Exceeding the 20% Policy Target)
The Challenge: Strict Local Planning Policy
South Gloucestershire Council has some of the strictest planning requirements in the region. For major greenfield developments like the 20-dwelling site at Engine Common, Policy PSP6 requires developers to reduce residual CO₂ emissions by at least 20% via renewable energy sources after energy efficiency measures are applied.
The challenge was not just to meet this target, but to demonstrate full compliance with the wider local plan (Policies CS1(8), CS3, and CS4) while accommodating a design change from 19 to 20 dwellings midway through the process.
Cotswold Homes needed a strategy that was robust enough to satisfy the climate officers, yet practical enough to build cost-effectively.
Our Approach: The Energy Hierarchy
To achieve the best results, we applied the energy hierarchy methodology—prioritising energy reduction before energy generation.
- Be Lean (Fabric First) – We started by reducing the buildings’ energy demand. By specifying high-performance insulation (Walls: 0.18 W/m²K; Roof: 0.10 W/m²K; Floors: 0.12 W/m²K) and targeting an air permeability of <5 m³/hr/m², we ensured the homes held onto heat efficiently.
- Result: A 4.5% reduction in CO₂ from fabric improvements alone.
- Be Green (Renewable Technology) – Initial modelling using traditional gas boilers showed high baseline emissions and would struggle to hit the aggressive carbon targets. We advised switching to a fully electric strategy, combining:
- Air Source Heat Pumps (ASHP): High-efficiency heat pumps for heating and hot water.
- Solar PV: We optimised the roof space to install a total array size of 37.61 kWp across the development, maximising generation on the most favourable elevations.
The Results: Smashing the Target
By moving away from gas and optimising the solar array, the development didn’t just meet the 20% target—it nearly tripled it.
- Total CO₂ Reduction: We achieved a 59.63% reduction in overall emissions (Regulated + Unregulated).
- Regulated Emissions: A massive 77.62% reduction in regulated energy.
- Carbon Saved: 25,802 kg of CO₂ saved compared to the baseline.
The final Sustainability Statement provided clear, irrefutable evidence of compliance, allowing the planning application to proceed smoothly.
Client Testimonial
Building Energy Experts produced a Sustainability & Energy Statement to support our planning application for 20 homes in Engine Common. They worked with our technical team to identify measures that would help energy savings across the development reduce residual carbon emissions. Despite the technical nature of the topic, the report was clear and concise and well received by the Council’s climate officers. I would happily recommend the team to other developers.
Ashley Grant, Planning Manager at Cotswold Homes
Facing strict planning conditions?
South Gloucestershire, Bristol and Bath all have unique (and difficult) sustainability policies. Don’t risk a planning rejection with a generic report.
Contact us today to ensure your Energy Strategy is compliant, cost-effective, and approved.
