ASHRAE 90.1-2019 Chapter 5

Prescriptive compliance, just follow the recipe

The checklist route through ASHRAE 90.1-2019. Meet every value in the table for your climate zone and you comply. Tighter envelope, tighter fenestration, more lighting controls than 2016. Same principle.

2019 Chapter 5 envelope tables, tighter than 2016
Section 6 HVAC efficiency, raised across the board
Reduced LPDs and expanded lighting controls
COMcheck-2019 tabulated compliance summary
3D building model showing geometry with blue walls, teal roofs, and orange adjacent structures in a grid layout within a design software interface.
Tighter than 2016, same shape

Built for clarity and constraint

The Prescriptive Compliance Path under ASHRAE 90.1-2019 works the same way it did under 2016: meet every value in the tables for your climate zone and building type, and you comply. The values are tighter. Envelope U-factors are lower, LPD allowances are reduced, skylight limits dropped from 5 to 3 percent, HVAC efficiencies raised. For projects that would sail through the 2016 prescriptive path, the 2019 version is worth a fresh look before assuming it still works. If it doesn't, ECB or Appendix G are waiting.
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.
Envelope Requirements

2019 tightened envelope U-factors and R-values across most climate zones compared with 2016. Tables 5.5-1 through 5.5-8 remain the reference, the numbers have moved.

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 Lookup

Climate zone assignment is unchanged from 2016. Chapter 5 sections A, B and C still split by heating and cooling degree days. Wrong zone, wrong table, wrong answer.

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.
Fenestration Limits

Vertical fenestration capped at 40 percent WWR. Skylights capped at 3 percent of gross roof area, down from 5 percent in 2016. Over either limit and you are on a performance path.

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 Performance

Maximum U-factor and SHGC set per climate zone and orientation, tightened in 2019 in most zones. The specification sheet is what the certifier will actually check.

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

Air barriers, continuous insulation and thermal bridging carry through from 2016 with tightened detailing requirements. Mandatory means mandatory on every pathway, not just prescriptive.

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 Requirements

Section 6 efficiency minimums raised across most equipment classes for 2019. Economiser triggers, ventilation control and energy recovery thresholds updated too. Read the whole section, do not assume 2016 still applies.

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.
Lighting Power Density

LPD allowances reduced across almost every space type in 2019, reflecting the shift to LED. Controls requirements expanded, particularly for daylight harvesting and parking areas.

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.
Service Water Heating

Section 7 requirements tightened in 2019 for pipe insulation and standby losses. Heat pump water heater efficiencies now on par with expectations for the technology.

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 Documentation

COMcheck-2019 or equivalent, with every prescriptive value shown against the 2019 tables. One missed value and the whole path fails, same as before.

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