EDGE Expert common mistakes
EDGE Expert · Understand the traps and how to avoid them.
Editing the EDGE base case - changing defaults, fuel types, or benchmark intensities - so that the improved case is compared against a friendlier baseline than the one the tool auto-populates for that location and building type.
The base case can look 'wrong' to a candidate who knows the actual building, and the software permits edits, so it is tempting to 'correct' it before modelling savings.
What to do instead
Leave the base case at the EDGE default for the project's country, climate zone and typology. If a deviation is genuinely required, record the justification, the data source, and flag it in the certification documentation so the auditor can review it.
Quoting a single blended 'savings' figure - e.g. averaging 35% energy, 12% water and 40% materials into 'about 29% overall' - and presenting the project as meeting the EDGE threshold.
The results screen shows three figures side by side and candidates carry the mental habit of a single performance score from other rating systems.
What to do instead
Read each category's percentage against its own base case and check each one clears the threshold independently. A project fails certification if any single category falls below 20%, regardless of the other two.
Assuming EDGE Advanced requires 40% savings in energy, water and materials simultaneously, and designing (or advising a client) accordingly.
The tiers are commonly summarised loosely as '20% then 40%', and candidates extrapolate the energy uplift to all three resource categories.
What to do instead
Memorise the tier structure explicitly: EDGE Certified = 20% in energy, water and embodied energy in materials; EDGE Advanced = 40% energy savings on-site plus 20% in water and materials; Zero Carbon = the top energy tier with the standard's carbon requirements. Apply the correct test per tier.
Treating certification as one submission made after construction, and only then engaging the third-party auditor - with no preliminary certification stage and no audit booked ahead of the final submission.
Candidates map EDGE onto certification schemes where a single as-built submission is normal, and project schedules push compliance work to the end.
What to do instead
Sequence it: preliminary certification at design stage on the model and drawings, then evidence collection during construction, then the independent EDGE audit, then final certification. Book the auditor early and confirm which documents they will sample.
Transplanting a measure package from a published case study or a previous project in a different climate - for example specifying high-performance double glazing and heavy insulation on a hot-humid project before any shading or massing strategy has been tested.
Case studies and measure libraries are readily available and visually persuasive, while climate-specific reasoning takes more work.
What to do instead
Start from the project's climate zone and the dominant load, rank measures by savings per unit cost in that specific model, and settle orientation, shading and envelope before specifying glazing or plant. Re-run each measure in the actual location rather than trusting the source project's numbers.
Claiming water savings from rainwater harvesting or greywater reuse without adding the pumping and treatment energy to the energy model.
Water and energy are separate EDGE modules and the water tab accepts alternative-source volumes without prompting for the associated energy.
What to do instead
Model the treatment and distribution energy in the energy module and report only the net water reduction. Check that the water gain has not quietly eroded the energy percentage below its threshold.
Specifying recycled-content or low-carbon materials that cannot actually be procured in the project's market, or ignoring the country-specific material baselines and transport distances built into EDGE.
Embodied energy in materials is the least familiar of the three categories, so candidates substitute generic green-material intuition for the tool's local baseline data.
What to do instead
Use the EDGE baselines supplied for that country, concentrate effort on the highest-mass and highest-intensity materials (concrete, steel, masonry, glazing), and confirm supplier evidence and haul distances before the measure is claimed.
Reaching for active measures - HVAC upgrades, heat pumps, PV arrays - as the first response to a client brief, before testing orientation, massing, shading, natural ventilation and envelope.
Active measures produce large percentage-point swings quickly in the model, whereas passive measures are slower to enter and their effects are split across several inputs.
What to do instead
Work the passive-first hierarchy explicitly: orientation and massing, then shading, then envelope, then efficient systems, then renewables. Present the client with the cost per percentage point saved for each tier so the cheapest savings are captured first.
Calculating payback on the total construction cost rather than on the incremental cost above the base-case design, and reporting it without a discount rate or asset life.
Clients supply a total budget, and simple payback on total cost is the easiest arithmetic to perform.
What to do instead
Compute incremental capex (improved case minus base case measure by measure), annual savings from the modelled consumption delta multiplied by local tariffs, then report simple payback and a life-cycle NPV using the client's discount rate and the asset's expected life.
Making unit and area errors when entering data - mixing gross floor area with conditioned area, entering monthly consumption as annual, or transposing kWh and MWh - and submitting the model without a sanity check.
Inputs are assembled from utility bills, drawings and vendor sheets in inconsistent units, and EDGE normalises results per square metre per year, which hides the scale of a mistake.
What to do instead
Reconcile the modelled floor area against the drawings, convert metered data to the same period and units as the bill, and benchmark the resulting kWh/m²/yr and litres/person/day against EDGE values for comparable buildings before submission.