The performance pathway for Section J. Model your building against a compliant reference, show it uses less energy, and stop letting a glazing calculator dictate your façade.


The reference model is generated to the DTS provisions for your climate zone and building class, so you are not hand-assembling a baseline and hoping the certifier reads it the same way you did.

Simulations run against the NCC climate zone weather file for your actual site. Get this one wrong and every number downstream is wrong with it, which is why it gets set once and left alone.

Walls, roofs and floors can move away from the DTS values as long as the building still lands under the reference. That flexibility is the whole reason the method exists.

Model the glazing you actually specified, not the glazing the DTS calculator is willing to tolerate. A large façade is usually the reason a project ends up on this pathway in the first place.

Overhangs, fins, screens and neighbouring buildings are modelled as real geometry. Shading then earns its keep properly instead of being approximated into a fudge factor.

Assign real system types and efficiencies to the proposed model while the reference holds the DTS baseline. Plant selection is one of the larger levers available to you here.

Lighting, equipment and occupancy schedules stay matched across both models. The comparison only means something if the loads on each side are identical.

Both models run a full year at hourly resolution through EnergyPlus. It takes minutes, not the overnight run you might still be bracing for.

Results come out as a side by side energy comparison with the assumptions documented alongside them, which is what the certifier will ask for regardless.
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