Energy Use Intensity (EUI) targets are the backbone of Colorado Regulation 28’s Prescriptive Pathway and percent-reduction calculations. Understanding what CDPHE expects for your building type—and how targets will evolve—is essential for planning realistic compliance strategies.
This guide breaks down EUI targets by building type, explains the methodology, and explores what the 2030 ratchet means for your long-term planning.
What Is Energy Use Intensity (EUI)?
EUI measures a building’s annual energy consumption normalized for building size:
EUI (kBtu/sq ft/year) = Total Annual Site Energy Consumption (kBtu) ÷ Gross Building Area (sq ft)
EUI captures “how much energy does this building use per unit of floor area?” It’s useful because it allows you to compare a 50,000 sq ft building to a 500,000 sq ft building on the same scale.
Example: Two office buildings
- Building A: 100,000 sq ft, 1,650,000 kBtu/year = 16.5 EUI
- Building B: 200,000 sq ft, 3,300,000 kBtu/year = 16.5 EUI
Both have the same EUI (16.5) even though Building B uses twice the total energy. This allows fair comparison across buildings of different sizes.
CDPHE’s Published Prescriptive EUI Targets
CDPHE has published targets for the following building categories (in kBtu/sq ft/year, Colorado climate-adjusted):
Commercial Buildings
| Building Type | 2026 Prescriptive Target | Estimated 2030 Target |
|---|---|---|
| Office | 16.5 | ~14.3 (13% reduction) |
| Retail | 18.2 | ~15.8 |
| Warehouse (Unrefrigerated) | 6.8 | ~5.9 |
| Refrigerated Storage | 35.0 | ~30.5 |
| Data Center | 45.0 | ~39.2 |
| Mixed-Use | Weighted average | Weighted average |
Multifamily & Hospitality
| Building Type | 2026 Target | Estimated 2030 Target |
|---|---|---|
| Multifamily Residential | 12.1 | ~10.5 |
| Hotel | 17.8 | ~15.5 |
| Assisted Living / Senior Care | 16.2 | ~14.1 |
Healthcare & Institutional
| Building Type | 2026 Target | Estimated 2030 Target |
|---|---|---|
| Hospital | 22.5 | ~19.6 |
| Medical Office | 19.8 | ~17.2 |
| Elementary School | 13.2 | ~11.5 |
| Secondary School | 14.1 | ~12.3 |
| Higher Education | 14.8 | ~12.9 |
Note: 2030 targets are CDPHE’s stated intention (29% reduction from 2021 baseline). Final 2030 targets may be adjusted and will be published by 2027.
How CDPHE Sets These Targets
1. ASHRAE Standard 100 Baseline
ASHRAE Standard 100 defines “Advanced Energy Design Guide” performance levels for each building type. These are derived from actual building performance data across the United States and represent approximately the 75th percentile of energy efficiency (better than 75% of existing buildings but not extreme outliers).
2. Colorado Climate Adjustment
Colorado’s climate is unique:
- High elevation (Denver: 5,280 ft; some areas 7,000–10,000 ft)
- Low humidity and solar radiation
- Cold, long winters; relatively short cooling seasons
These factors mean Colorado buildings require less cooling energy than national averages, so CDPHE adjusts targets downward. A national ASHRAE target of 18 kBtu/sq ft/year might become 16.5 in Colorado.
3. Building Type Specificity
Different building types have fundamentally different energy profiles:
- Warehouses: Minimal HVAC and lighting = low EUI (6–8)
- Offices: Moderate HVAC, significant lighting and plug loads = moderate EUI (15–18)
- Data centers: 24/7 cooling and power = very high EUI (40–60)
- Hospitals: 24/7 operation, sterile conditions, high plug loads = high EUI (20–25)
CDPHE publishes category-specific targets reflecting these differences.
Actual Colorado Building Performance vs. Targets
How are Colorado buildings actually performing against these targets?
Buildings Beating Targets (Below):
- Modern office buildings (built post-2010) with efficient HVAC and controls: 12–15 EUI
- New retail with LED lighting and occupancy controls: 14–16 EUI
- Well-maintained warehouses: 4–6 EUI
- On-site renewable energy reduces effective EUI: can cut 10–20% off baseline
Buildings Struggling With Targets (Above):
- Pre-1990 office buildings without major upgrades: 18–25 EUI
- Older multifamily housing: 13–16 EUI (target is 12.1)
- Legacy hospitals and medical offices: 24–30 EUI
- Data centers and server farms: 50–100+ EUI
Typical compliance profile: ~40% of Colorado’s covered buildings currently meet prescriptive targets; 60% require improvements or alternate pathways.
The 2030 Ratchet: How Targets Escalate
Regulation 28 includes a second compliance phase starting January 1, 2030. The ratchet works as follows:
2026 Compliance: Buildings must achieve 13% reduction from 2021 baseline OR meet prescriptive EUI target
2030 Compliance: Buildings must achieve 29% reduction from 2021 baseline OR meet tightened EUI targets
For percent-reduction pathways, the math is straightforward:
- 13% reduction by 2026
- Additional 16% reduction by 2030 (29% total)
For prescriptive pathways, CDPHE will publish tightened targets around 2027–2028. Conservative estimates:
| Building Type | 2026 Target | Estimated 2030 Target | Tightening |
|---|---|---|---|
| Office | 16.5 | ~14.3 | -13% |
| Retail | 18.2 | ~15.8 | -13% |
| Multifamily | 12.1 | ~10.5 | -13% |
| Hospital | 22.5 | ~19.6 | -13% |
The 13% tightening aligns with Regulation 28’s statement that second-phase targets will be approximately 29% total reduction.
Strategic Implications of the 2030 Ratchet
Buildings should plan compliance strategies with 2030 in mind:
Strategy 1: Phase Implementation
Rather than a single retrofit, plan improvements in phases:
- Phase 1 (2026): Low-cost ECMs (lighting, controls) to meet 2026 targets
- Phase 2 (2028–2030): Capital-intensive improvements (HVAC, envelope) to hit 2030 targets
This spreads cost and allows operational cash flow to fund improvements.
Strategy 2: Renewable Energy as Backstop
Renewable energy (solar, wind, clean power contracts) doesn’t degrade over time. If you achieve prescriptive compliance in 2026 using a solar installation, that investment will still serve you in 2030.
Contrast with efficiency improvements: a lighting retrofit saves the same percentage in 2026 and 2030, so you need additional ECMs to hit the 2030 ratchet.
Strategy 3: Pathway Selection Based on Long-Term Economics
Some buildings that meet 2026 prescriptive targets won’t meet 2030 targets without additional improvements. At the 2026 deadline, consider:
- Can you cheaply achieve 2030 targets now? (Do it—operational efficiency is the best strategy)
- Can you install renewable energy now? (Yes—it locks in compliance for 2030)
- Will 2026 target be unachievable by 2030 without major capex? (Consider percent-reduction or GHG pathways instead; they offer more flexibility)
EUI Targets for Mixed-Use Buildings
Many Colorado buildings serve multiple purposes. CDPHE allows “blended” EUI targets for buildings with multiple primary uses.
Example: A building is 65% office, 35% retail.
- Office target: 16.5
- Retail target: 18.2
- Blended target: (0.65 × 16.5) + (0.35 × 18.2) = 10.725 + 6.37 = 17.095
You’d need to document the square footage breakdown and justify the percentages. Your energy auditor should calculate this.
Note: CDPHE looks skeptically at buildings claiming “mixed-use” to justify higher targets. If you claim 35% retail to raise your target, be prepared to document that 35% of your square footage is actually retail.
Comparing Colorado Targets to National Standards
How do Colorado’s targets compare to national ASHRAE standards?
| Building Type | ASHRAE Nat’l Benchmark (75th percentile) | Colorado Target | Difference |
|---|---|---|---|
| Office | 18–20 | 16.5 | -10 to -15% |
| Retail | 20–22 | 18.2 | -10 to -15% |
| Warehouse | 7–8 | 6.8 | -5 to -15% |
| Multifamily | 13–14 | 12.1 | -5 to -10% |
Colorado’s targets are 10–15% stricter than national ASHRAE benchmarks. This reflects Colorado’s climate advantage and also CDPHE’s intent to push buildings toward real efficiency (not just “average”).
Using EUI Data for Your Compliance Strategy
Step 1: Calculate Your Current EUI
Gather 2021–2025 utility data, calculate site EUI using methods described above.
Step 2: Identify Your Building Type and Target
Work with your auditor to confirm your building’s primary use type and CDPHE target.
Step 3: Compare and Gap Analysis
- If Current EUI ≤ Target: Prescriptive pathway may work
- If Current EUI > Target by 5–10%: Low-cost ECMs might close the gap
- If Current EUI > Target by 15%+: Percent-reduction or GHG pathway likely more feasible
Step 4: Plan for 2030
- If you barely meet 2026 target, assume you won’t meet 2030 target
- Plan ECMs that scale; don’t assume 2026 will be “enough”
- Consider renewable energy or long-term efficiency roadmap
Step 5: Model Pathways
Your energy auditor should model all four pathways and recommend the most achievable and economical for your building.
Bottom Line
EUI targets are the measuring stick for Regulation 28 compliance. Understanding what CDPHE expects for your building type, how targets are set, and how they’ll change in 2030 is essential for smart compliance planning.
Buildings that beat targets now will likely beat tightened 2030 targets. Buildings that barely meet 2026 targets should plan additional improvements for 2028–2030.
Know your current EUI. Know your target. Plan accordingly.