ASHRAE 90.1-2019 Section 11

Compliance measured on annual energy cost

Section 11 of ASHRAE 90.1-2019. Model the proposed design against a budget building built from the 2019 prescriptive requirements. If the proposed costs the same or less to run, you comply.

Budget building generated to 2019 prescriptive Section 5, 6, 9
Hourly annual simulation, climate zone weather
Envelope, glazing and HVAC trade-offs balanced by cost
Section 11.7 documentation ready for review
3D building model showing geometry with blue walls, teal roofs, and orange adjacent structures in a grid layout within a design software interface.
Modelling, not checklists

Designed for trade-offs, not just tables

Section 11 of ASHRAE 90.1-2019 keeps the Energy Cost Budget Method almost exactly as it was in 2016, except the budget building is now assembled from the 2019 prescriptive tables. Same two-model comparison, same annual cost metric, same trade-off flexibility. The catch is that a 2019 budget building runs on less energy than a 2016 one, so if you were scraping past ECB compliance under 2016 you may need to work harder in 2019. The method itself has not changed. The numbers around it have.
Digital floor plan highlighting Diesel Tank Room in green, adjacent to Diesel Pump Room and MSB Room, with navigation and editing tools on the interface.
Budget Building

Same shape and size as the proposed, but with envelope, HVAC and lighting at the 2019 prescriptive minimums. Tighter than a 2016 budget building, which matters at the margins.

Digital architectural floor plan interface showing Level B1 layout with highlighted Access Room and editing tools for opacity and color on the blueprint.
Climate Zone Weather

Both models run against identical ASHRAE climate zone weather data. TMY3 or ASHRAE-provided is the expectation, applied consistently to both.

Screenshot of betterbuilding software showing a tags panel with categorized building elements like windows, walls, floors, roof, and retail, alongside a level navigation menu on the left.
Envelope Trade-offs

Extra insulation somewhere buys weaker glazing elsewhere, provided annual cost lands. A tighter 2019 budget building makes some 2016-era trade-offs harder to justify.

Screenshot of a building management software interface showing a list of building levels with options to edit, duplicate, or access roof geometry for Level 03.
Glazing Optimisation

Fenestration modelled as designed in the proposed. Under 2019, high-performance glazing has to work harder to beat a stiffer budget number.

3D building model in Betterbuilding software showing color-coded wall shading and window elements with controls and a simulations panel on the right.
Shading Geometry

Overhangs, fins and adjacent buildings as real geometry in the proposed. The budget building's shading is still limited by table, which is a difference you can lean into.

User interface of Betterbuilding software showing solar panel renewables settings including surface coverage 100%, cell efficiency 18%, azimuth 0°, tilt 5°, and row size 1.55 meters, with a rectangular solar array preview on the right.
HVAC Systems

Proposed uses your specified plant. Budget uses a 2019 system type from Section 11.5.2, with 2019 efficiency minimums. Baseline efficiencies are higher than they were, so your HVAC has less easy margin.

Betterbuilding interface showing Wall tags and detailed settings for External Wall and Internal Wall, including R-value, solar absorptance, exposure, thickness, density, and heat capacity sliders.
Matched Loads

Lighting, plug loads, occupancy, ventilation and service water heating identical across both models. Only the regulated systems and the envelope get to move.

Betterbuilding software interface showing Spaces tab with building zones and settings for Occupants including Design Level, Activity Level, Air Velocity, Work Efficiency, and Clothing Method.
Annual Cost Simulation

Full year hourly simulation of both models, costed against project utility rates. Cost is the metric, and rate structure choices can swing outcomes at the edges.

Betterbuilding software interface showing energy consumption summary for Example Building with proposed versus reference data, including bar charts and tables of electricity use by category and monthly energy breakdown.
Compliance Report

Proposed cost at or below budget cost, with Section 11.7 documentation: inputs, weather file, rates, software, and the reasoning for any judgement calls.

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