HVAC Ductwork, Air Handling & Mechanical Products worked example

Energy Rating Margin with achieved energy efficiency rating of 0.59 units: a worked example

Here is what the math looks like when conditions slip. We hold every other input steady and drop achieved energy efficiency rating to 0.59 units, then walk the calculation through step by step. Check how much margin an air handling unit or fan coil has against the minimum energy efficiency rating required by code or contract. Enter the achieved rating, the minimum required rating, and the reference value to calculate the margin and the percentage above the threshold.

The inputs for this scenario

  • Achieved energy efficiency rating: 0.59 units (the input this scenario stresses; the baseline uses 1.18)
  • Minimum required rating (code or spec): 1 units (held at the documented default)
  • Reference value for margin calculation: 1 units (held at the documented default)

Working through the calculation

  • The calculation starts from the formula this tool documents: Energy rating margin = achieved rating - minimum required rating.
  • Margin works out to -41 % at these inputs, and this is the headline figure for the scenario.
  • Absolute margin works out to -0.41 value at these inputs.
  • Available amount works out to 0.59 value at these inputs.
  • Required amount works out to 1 value at these inputs.

How this compares with the baseline

  • Against the tool's baseline example, where achieved energy efficiency rating sits at 1.18 units and the headline result is 18 %, this scenario comes in 328% below the baseline at -41 %.
  • The practical read: the gap between this scenario and the baseline is entirely attributable to achieved energy efficiency rating, so recovering it is worth quantifying in dollars before considering equipment or staffing changes. It is a single-point margin against one rating figure; it does not capture part-load performance, test uncertainty bands or field degradation, so a positive margin still needs validation against rated-condition tolerances.

Results at a glance

  • Margin: -41 % (headline result)
  • Absolute margin: -0.41 value
  • Available amount: 0.59 value
  • Required amount: 1 value

Run it with your numbers

  • To rerun this with your own numbers, open the live Energy Rating Margin calculator, set achieved energy efficiency rating to your actual value, and adjust the remaining inputs to match your operation.

Last reviewed 2026-05-12.