The League Table & Rafts Methodology

A systematic, evidence-based framework for ranking every possible energy-improvement measure and turning the ranked list into three costed, cumulative implementation pathways. Applied consistently across every DEAR and NDEAR advice report we lodge.

Two advice-report families: DEAR and NDEAR

DEAR (Domestic Energy Advice Report) uses RdSAP 10 for residential dwellings. NDEAR (Non-Domestic Energy Advice Report) uses iSBEM for commercial properties, including owner-occupier engagements with specific operational objectives.

Stage 1 — The League Table

We establish a baseline RdSAP or SBEM model and then model each candidate improvement measure separately against it. Measures are ranked across five criteria: EPC points gained, energy saving (kWh/m²/yr), CO₂ reduction, cost saving (£/yr) and payback period. Non-domestic measures also carry the MEES 7-year payback test flag.

Stage 2 — The Rafts

Top-ranked measures are grouped into three cumulative implementation stages: Raft 1 (priority measures achieving current minimum compliance), Raft 2 (Band C mid-term target) and Raft 3 (deep retrofit toward Band A/B). Each Raft is re-modelled as a stacked scenario — arithmetic addition of isolated League Table results is not valid because measure interactions in SBEM and RdSAP are non-linear.

Why BER, not TER, for non-domestic carbon comparison

BER (Building Emission Rate) reflects the actual as-modelled building performance independent of the notional target. TER (Target Emission Rate) only shows compliance headroom against a moving target. BER gives a cleaner comparison for measure impact.

Declared model limitations

Every advice report we issue carries plain-English notes on RdSAP/SBEM model limitations (standard occupancy assumptions, SBEM lighting anomalies, air-permeability defaults) and on cost/fuel-price uncertainty. Independent consultancy means declaring what the model can and cannot do.

Quality assurance

Every report goes through a six-step QA process: baseline verification, measure-isolation verification, metric extraction cross-check, League Table anomaly review, Raft cumulation verification, and figure-to-model traceability. Assessments are lodged under Quidos accreditation QUID201039.

Frequently asked questions

Why do you use BER rather than TER for non-domestic carbon comparison?

BER (Building Emission Rate) reflects actual as-modelled performance independent of the notional target building. TER (Target Emission Rate) only shows compliance headroom against a moving target. For advice work — where we are comparing measure impact — BER gives a cleaner apples-to-apples view.

Why isolate each measure rather than stacking them?

Because measure interactions in SBEM and RdSAP are non-linear. Stacking prematurely obscures which measure actually delivered the improvement. Isolation lets us rank fairly across five criteria, then re-stack cumulatively as Rafts for real-world implementation planning.

Why five scoring criteria and not one?

A one-number score always privileges one dimension (usually carbon or cost) and hides trade-offs. Landlords care about £/yr; regulators care about EPC band; carbon reporting cares about kgCO₂/m²/yr; investors care about payback. Ranking across all five surfaces the measure that wins on the criterion the client cares about most.

What is the 7-year payback test?

The Minimum Energy Efficiency Standard (MEES) for non-domestic property requires improvement measures to pay back within 7 years to be enforceable. Our League Table flags every non-domestic measure against this test so landlords can filter compliance-mandatory measures from optional carbon-abatement measures.

How does DEAR differ from NDEAR?

DEAR uses RdSAP 10 for residential dwellings; NDEAR uses iSBEM for non-domestic (commercial) properties. Both apply the League Table + Rafts methodology, but the metrics differ: DEAR ranks by SAP points, kWh/m²/yr, tonnes CO₂/yr, £/yr and payback. NDEAR ranks by SBEM asset rating, BER, total energy, £/yr and payback with the 7-year test flag. NDEAR also covers non-MEES engagements — for example, owner-occupiers looking at cold rooms, carbon reporting or plant-replacement decisions — with complementary heat-loss calculations added where the brief requires.

Are Raft cost estimates guaranteed?

No. Costs are indicative benchmarks from 2024–2026 market data. Every Raft report tells you to obtain three contractor quotes before committing. Where a client provides real quotes, we replace the indicative figures and re-run the Raft calculation.

Is this methodology accredited or externally reviewed?

Our energy assessments are lodged under Quidos accreditation (QUID201039). The League Table + Rafts methodology itself is a proprietary Energy Performance Direct process — publicly documented on this page for transparency, and applied consistently across every DEAR and NDEAR report we lodge.

How is this methodology different from a standard EPC recommendations report?

A standard EPC recommendation list gives a fixed set of measures with no ranking, no interaction modelling, and no capital cost figures. Our League Table + Rafts approach ranks every measure across five criteria, tests them individually then cumulatively, and reports three costed implementation pathways with modelled band outcomes. It's an independent consultancy output, not a compliance form.

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