The deviation that invalidates the calculation
The credit states it verbatim:
"Unlike in Appendix G, performance improvements within the Pearl Rating System are based on reductions in annual energy consumption (kWh) rather than cost, thus all reference to energy rates within Appendix G must be ignored."
Appendix G of ASHRAE 90.1 rates performance by cost. The Pearl Rating System rates it by energy. A team that follows Appendix G literally — as checklists carried over from other systems advise — produces an improvement percentage that measures something the credit does not.
What RE-R1 states
| Item | Requirement |
|---|---|
| Minimum | 12% improvement over baseline performance |
| Points | None — "This is a requirement. There are no Credit Points awarded" |
| Methodology | Appendix G of ANSI/ASHRAE/IESNA 90.1-2007 |
| Mandatory provisions | Sections 5.4, 6.4, 7.4, 8.4, 9.4 and 10.4 of 90.1-2007 |
| Baseline standards | 90.1-2007 or local code, whichever is more stringent |
| Air leakage | 3.64 l/s/m² at 75 Pa or local code, whichever is more stringent — modelled identically in both models |
| Climate zone | 1B "Very Hot and Dry" is assumed for projects in the Emirate of Abu Dhabi |
| Submission | Energy Model Template summarizing the dynamic energy simulation |
The eight end-use load components
Both the proposed and the baseline building performance must include all of these:
- Lighting
- Heating
- Cooling
- Heat rejection — frequently omitted
- Pumps
- Fans
- Service water heating
- Receptacle and process loads
Requirements on the modelling itself
- The same simulation software and the same weather data for both models — "with approval from Estidama". Not a published list of approved tools to pick from, but approval for your project.
- Receptacle and process loads must be modelled identically in both models.
- Tenant fit-out areas outside developer control are also modelled identically, unless tenant guidelines are provided under
IDP-R2. - Mixed mode ventilation: to claim its savings, credit
LBi-5.3Thermal Comfort Modelling must be achieved for those areas. - Mixed-use developments are modelled as a single building; baseline HVAC per
G3.1.1, and envelope parameters set by occupancy type.
A route you may not know: the exceptional calculation method
For components the simulation program cannot adequately model, Estidama may approve an exceptional calculation method — as outlined in Appendix G — demonstrating savings through calculations performed by the design team, supported by theoretical and/or empirical information establishing the method's accuracy.
Attributed to Estidama, but not in it
Occurrence counts across the full 223-page manual for the phrases that circulate:
| Commonly asserted | Occurrences in the manual |
|---|---|
| Unmet load hours ≤ 300 | Zero |
| An approved software list | Zero |
Matching IFC drawings | Zero |
| "Estidama default schedule profiles" | No such thing |
| Auditors reviewing raw simulation files | Zero — the submission is the Energy Model Template |
This does not make those items technically wrong. The 300-hour limit, for instance, is in Appendix G itself and applies by reference because the credit adopts the Appendix G methodology. But the distinction matters in practice: what Estidama wrote, you are asked about directly; what comes by reference, you are asked about as part of Appendix G — and you do not attribute to Estidama a requirement it did not write.
Frequently Asked Questions
Do I calculate the improvement on cost, as Appendix G does?
No. The Pearl Rating System measures in kWh and instructs that all reference to energy rates in Appendix G be ignored. A cost-based calculation produces a figure the credit does not measure.
Which software is approved by Estidama?
The manual publishes no list. It requires appropriate dynamic simulation software and the same program for both models, with approval from Estidama — approval attaches to your project rather than to a menu you choose from.
Is the 300 unmet load hours limit an Estidama requirement?
It does not appear in the Pearl Rating System manual at all. It comes from Appendix G of ASHRAE 90.1 and applies because the credit adopts that methodology — so cite it to ASHRAE, not to Estidama.
Which climate zone do I model?
The manual assumes zone 1B "Very Hot and Dry" for projects in the Emirate of Abu Dhabi, based on section B2 of 90.1-2007.