EDGE Expert cheat sheet

EDGE (Excellence in Design for Greater Efficiencies) is a free, web-based modeling tool developed by IFC; a full model typically needs only about 20 inputs to generate results.

Three-step workflow: define the base case from the tool's benchmarks, select measures to build the proposed case, then read the results dashboard and measures report.

Savings formula, applied separately to each resource: % savings = (base case value − proposed case value) / base case value × 100.

Reporting units: energy in kWh/m²/year; water in m³ per occupant per year (residential) or per unit (commercial); materials in MJ of embodied energy per m².

The base case is auto-populated from EDGE's climate- and typology-specific benchmark database covering 180+ countries; overriding it requires documented justification.

The measures library is filtered to options applicable to the chosen building typology (residential, office, hotel, hospital, retail, education, warehouse) and climate zone.

Results output includes savings percentages plus financial indicators: incremental capital cost, annual utility savings, payback period, and cash-flow projections.

Certification levels modeled in the software: EDGE Certified at 20% savings across all three categories, EDGE Advanced at ≥40% on-site energy savings, EDGE Zero Carbon at 100% renewable or offset energy.

Modeled inputs become the audit baseline, so the final as-built submission must match the installed measures or the model must be re-run and resubmitted.

EDGE is a green building certification and software system created by IFC (World Bank Group), designed for new and existing buildings in emerging markets.

Threshold rule: a project must show at least 20% predicted savings versus the base case in energy, water, AND embodied energy in materials - all three are mandatory.

Certification tiers: EDGE Certified (20% in all three categories), EDGE Advanced (≥40% energy savings achieved on-site), EDGE Zero Carbon (100% of operational energy from renewables or verified offsets).

Two-stage audit sequence: a preliminary certificate at design stage based on drawings and specifications, then a final certificate after construction confirms as-built compliance.

Certification is issued by independent, IFC-accredited providers (for example GBCI, SGS, BRE, TÜV); the EDGE Expert models and advises but cannot audit their own project.

Cost structure: the software is free; providers charge a registration fee plus a certification fee scaled to gross floor area.

Evidence required: signed declarations, architectural and MEP drawings, equipment schedules and specifications, plus a site inspection for the final certificate.

The preliminary certificate has a limited validity period (typically two to three years) and lapses if construction does not complete within it; the final certificate does not expire.

EDGE Zero Carbon additionally requires the 20% energy, water, and materials savings plus documented renewable supply or offsets for all remaining energy use.

Hot-humid climate: prioritize external shading, low-SHGC glazing, high-SRI cool roofs, ceiling insulation, and cross ventilation; heating measures yield negligible savings.

Hot-dry climate: pair thermal mass with night-flush ventilation, add external shading and evaporative cooling, and specify xeriscaping and drip irrigation.

Cold climate: roof and wall insulation, low U-value double or triple glazing, airtightness, and heat-recovery ventilation dominate the savings stack.

Temperate climate: moderate insulation plus operable windows and mixed-mode HVAC; savings come mostly from lighting, appliances, and part-load HVAC efficiency.

Core EDGE energy measures: LED lighting, higher-efficiency HVAC (COP/EER), roof and wall insulation, glazing upgrades, solar water heating, and rooftop PV.

Core EDGE water measures: low-flow taps, showers and dual-flush WCs, leak detection, sub-metering, rainwater harvesting, greywater recycling, and efficient landscaping.

The water base case scales with local scarcity and occupancy assumptions, so the same fixture package shows larger percentage savings in high-consumption benchmarks.

Materials measures cut embodied energy: AAC blocks, fly-ash-blended concrete, recycled steel, alternative walling and roofing, reduced finishes, and locally sourced materials.

Renewable output depends on local solar irradiance (annual kWh per kWp), so identical PV capacity yields different percentage savings across locations.

Orientation rule: align the long axis east-west to minimize east and west façade area, which receive low-angle sun that is hardest to shade.

Window-to-wall ratio: keep glazing moderate (commonly ≤40% in hot climates) - raising it increases both daylight and cooling load, so optimize rather than maximize.

Shading geometry: horizontal overhangs on the equator-facing façade block high summer sun while admitting low winter sun; vertical fins control east and west exposure.

Natural ventilation rules of thumb: single-sided ventilation is effective to about 6 m depth, cross ventilation to about 12–15 m, with operable openings sized as a percentage of floor area.

Thermal mass pays off where the diurnal temperature swing exceeds roughly 8–10 °C and is combined with night ventilation; in hot-humid climates it risks overheating.

Simple payback = incremental cost / annual utility savings; use it for screening only, because it ignores the time value of money and energy price escalation.

Life-cycle cost = initial cost + present value of operating, maintenance, and replacement costs − residual value; discount future savings at the project's real discount rate.

Decision rule: rank measures by incremental cost per percentage point of savings and fund the low-cost, high-savings items (lighting, fixtures, insulation) before capital-intensive ones.