# Energy Codes and Compliance

## Code Framework

### Primary Energy Codes
| Code | Jurisdiction | Application |
|------|--------------|-------------|
| IECC | Model code (adopted by states) | Commercial and residential |
| ASHRAE 90.1 | Referenced standard | Commercial buildings |
| Title 24 | California | All buildings in CA |
| NYCECC | New York City | NYC buildings |
| Stretch codes | Various localities | Beyond base code |

### IECC Editions
| Edition | Key Changes |
|---------|-------------|
| 2021 IECC | ERI path, solar-ready, EV-ready |
| 2018 IECC | Increased envelope, lighting efficiency |
| 2015 IECC | Air barrier requirements |
| 2012 IECC | Blower door testing required |

### Adoption by State
| Adoption Level | States |
|----------------|--------|
| 2021 IECC | CA, WA, OR, VT, MA |
| 2018 IECC | NY, NJ, MD, VA, CO |
| 2015 IECC | TX, FL, GA, NC |
| 2012 or older | Many southern/rural states |

---

## Compliance Paths

### IECC Commercial Compliance
| Path | Description | Best For |
|------|-------------|----------|
| Prescriptive | Meet each requirement individually | Simple buildings |
| Trade-off (COMcheck) | Trade between components | Moderate flexibility |
| Energy Cost Budget | Whole-building simulation | Maximum flexibility |

### IECC Residential Compliance
| Path | Description | Best For |
|------|-------------|----------|
| Prescriptive | Meet all requirements | Standard construction |
| UA Trade-off | Trade envelope components | Design flexibility |
| Simulated Performance | Energy modeling | Custom designs |
| ERI (HERS) | Energy Rating Index | High-performance |

### ASHRAE 90.1 Compliance
| Path | Description |
|------|-------------|
| Prescriptive | Section-by-section requirements |
| Trade-off (ECB) | Energy Cost Budget method |
| Performance (PRM) | Performance Rating Method |
| Appendix G | Detailed simulation rules |

---

## Envelope Requirements

### Climate Zones
| Zone | Description | Examples |
|------|-------------|----------|
| 1 | Very Hot-Humid | Miami, Key West |
| 2 | Hot-Humid | Houston, Tampa, Phoenix |
| 3 | Warm | Atlanta, Dallas, LA |
| 4 | Mixed | NYC, DC, Seattle |
| 5 | Cool | Chicago, Denver, Boston |
| 6 | Cold | Minneapolis, Milwaukee |
| 7 | Very Cold | Duluth, Fargo |
| 8 | Subarctic | Fairbanks |

### Wall Insulation (Commercial - 2021 IECC)
| Climate Zone | Steel Frame | Mass Wall | Wood Frame |
|--------------|-------------|-----------|------------|
| 1 | R-13 | R-5.7ci | R-13 |
| 2 | R-13 + R-3.8ci | R-7.6ci | R-13 + R-3.8ci |
| 3 | R-13 + R-3.8ci | R-9.5ci | R-13 + R-3.8ci |
| 4 | R-13 + R-7.5ci | R-11.4ci | R-13 + R-7.5ci |
| 5 | R-13 + R-7.5ci | R-13.3ci | R-13 + R-7.5ci |
| 6-8 | R-13 + R-15.6ci | R-15.2ci | R-13 + R-15.6ci |

### Roof Insulation (Commercial - 2021 IECC)
| Climate Zone | Insulation Entirely Above Deck |
|--------------|-------------------------------|
| 1 | R-25ci |
| 2-3 | R-30ci |
| 4-5 | R-35ci |
| 6-8 | R-40ci |

### Fenestration (Commercial - 2021 IECC)
| Climate Zone | U-Factor | SHGC |
|--------------|----------|------|
| 1 | 0.50 | 0.25 |
| 2 | 0.45 | 0.25 |
| 3 | 0.42 | 0.25 |
| 4 | 0.38 | 0.38 |
| 5 | 0.36 | 0.38 |
| 6 | 0.34 | 0.40 |
| 7-8 | 0.32 | 0.45 |

### Residential Envelope (2021 IECC)
| Climate Zone | Ceiling | Wall | Floor | Fenestration U |
|--------------|---------|------|-------|----------------|
| 1 | R-30 | R-13 | R-13 | 0.40 |
| 2 | R-38 | R-13 | R-13 | 0.40 |
| 3 | R-38 | R-20 or R-13+5 | R-19 | 0.32 |
| 4 | R-49 | R-20 or R-13+5 | R-19 | 0.32 |
| 5-8 | R-49 | R-20+5 or R-13+10 | R-30 | 0.30 |

---

## Air Barrier Requirements

### Commercial Air Barrier
| Requirement | Standard |
|-------------|----------|
| Continuous air barrier | Required all climate zones |
| Material air permeance | ≤ 0.004 cfm/sf at 0.3" w.c. |
| Assembly air leakage | ≤ 0.04 cfm/sf at 0.3" w.c. |
| Building air leakage | ≤ 0.40 cfm/sf at 0.3" w.c. |

### Residential Air Sealing
| Climate Zone | Maximum ACH50 |
|--------------|---------------|
| 1-2 | 5 ACH50 |
| 3-8 | 3 ACH50 |

### Critical Air Barrier Locations
- Window and door frames
- Utility penetrations
- Rim joists
- Top plates
- Recessed lighting
- HVAC registers
- Electrical boxes

---

## Lighting Requirements

### Interior Lighting Power (ASHRAE 90.1-2019)
| Building Type | LPD (W/sf) |
|---------------|------------|
| Office | 0.79 |
| Retail | 1.05 |
| School | 0.81 |
| Healthcare | 0.96 |
| Hotel guest rooms | 0.56 |
| Warehouse | 0.45 |
| Restaurant | 0.90 |

### Lighting Controls Required
| Control | Requirement |
|---------|-------------|
| Occupancy sensors | Classrooms, restrooms, offices |
| Daylight responsive | Sidelit and toplit zones |
| Automatic shutoff | Scheduled or occupancy |
| Manual dimming | Open offices |

### Exterior Lighting Power
| Zone | Allowance |
|------|-----------|
| LZ0 (parks) | No lighting |
| LZ1 (rural) | Base + 500W |
| LZ2 (residential) | Base + 600W |
| LZ3 (commercial) | Base + 750W |
| LZ4 (high-activity) | Base + 1,300W |

---

## HVAC Requirements

### Equipment Efficiency Minimums
| Equipment | Efficiency | Standard |
|-----------|------------|----------|
| Split AC (< 65 kBtu) | 14 SEER | Federal minimum |
| Split AC (≥ 65 kBtu) | 11.2 EER | ASHRAE 90.1 |
| Packaged rooftop | 10.8-11.2 EER | By size |
| Gas furnace | 80% AFUE | Federal minimum |
| Heat pump | 8.8 HSPF | Federal minimum |
| Chiller (scroll) | 9.7 IPLV | ASHRAE 90.1 |
| Chiller (centrifugal) | 6.1 IPLV | ASHRAE 90.1 |
| Boiler (gas) | 80% Et | Federal minimum |

### Economizer Requirements
| Climate Zone | Cooling Capacity | Requirement |
|--------------|------------------|-------------|
| 1A, 1B | Any | Not required |
| 2A | Any | Not required |
| 2B, 3A-8 | ≥ 54 kBtu | Air economizer |
| All (water) | ≥ 135 kBtu | Water economizer |

### Ventilation
| Standard | Purpose |
|----------|---------|
| ASHRAE 62.1 | Commercial ventilation rates |
| ASHRAE 62.2 | Residential ventilation |
| ERV/HRV required | Climate zones 3-8, high OA |

---

## Service Water Heating

### Water Heater Efficiency
| Type | Efficiency |
|------|------------|
| Gas storage (≤ 55 gal) | 0.64 UEF |
| Gas storage (> 55 gal) | 0.77 Et |
| Electric storage (≤ 55 gal) | 0.93 UEF |
| Heat pump water heater | 2.0+ UEF |
| Gas tankless | 0.87 UEF |

### Piping Insulation
| Pipe Size | Insulation Thickness |
|-----------|---------------------|
| < 1" | 1" |
| 1" - 1.5" | 1.5" |
| > 1.5" | 2" |

### Solar Water Heating
- Required in some jurisdictions (Hawaii)
- Solar fraction targets: 50-70%
- Solar-ready provisions in 2021 IECC

---

## Documentation Requirements

### COMcheck Compliance
| Required Information | Source |
|---------------------|--------|
| Building area by use | Drawings |
| Envelope assemblies | Specifications |
| Fenestration schedule | Drawings |
| Lighting power | Lighting schedule |
| HVAC equipment | Mechanical schedule |

### Energy Modeling Documentation
| Document | Content |
|----------|---------|
| Building description | Geometry, orientation |
| Envelope | U-factors, SHGC, areas |
| HVAC systems | Equipment, controls |
| Schedules | Occupancy, lighting, HVAC |
| Baseline | Code-compliant reference |
| Results | Energy use comparison |

### Submittals Required
| Phase | Documents |
|-------|-----------|
| Permit | COMcheck/REScheck report |
| Permit | Mechanical equipment schedules |
| Construction | Equipment submittals |
| Final | Testing reports (blower door) |
| Final | Commissioning report (if req'd) |

---

## Testing and Verification

### Blower Door Testing
| Building Type | Requirement |
|---------------|-------------|
| Residential | Required (3-5 ACH50) |
| Commercial (small) | Optional path |
| Commercial (large) | Sampling allowed |

### Duct Leakage Testing
| Condition | Maximum Leakage |
|-----------|-----------------|
| Ducts outside envelope | 4 cfm/100 sf |
| Ducts inside envelope | 4 cfm/100 sf (or exempt) |

### HVAC Commissioning
| Building Size | Requirement |
|---------------|-------------|
| > 25,000 sf | Cx plan required |
| > 50,000 sf | Full commissioning |
| Complex systems | Functional testing |

---

## Beyond Code Programs

### ENERGY STAR
| Program | Requirement |
|---------|-------------|
| Homes | HERS ≤ 55-65 (by climate) |
| Multifamily | EPA certification |
| Commercial | Score ≥ 75 |

### Zero Energy Ready
| Program | Key Requirements |
|---------|------------------|
| DOE ZERH | HERS ≤ 45, solar-ready |
| Passive House | 4.75 kBtu/sf heating |
| LEED Zero | Net zero energy verified |

### Stretch Codes
| Jurisdiction | Above Base Code |
|--------------|-----------------|
| MA Stretch | ~10% better than IECC |
| CA Reach | ~15% better than T-24 |
| NYC LL97 | Carbon caps (2024+) |

---

## Common Compliance Issues

### Design Phase
| Issue | Solution |
|-------|----------|
| Window area too high | Reduce glazing or improve U/SHGC |
| Insufficient insulation | Add continuous insulation |
| Missing air barrier | Specify continuous barrier |
| Lighting over budget | Reduce LPD, add controls |

### Construction Phase
| Issue | Solution |
|-------|----------|
| Thermal bridging | Specify thermal breaks |
| Air barrier gaps | Continuous inspection |
| Duct leakage | Pre-cover testing |
| Missing insulation | Photo documentation |

### Inspection Points
| Trade | Inspection |
|-------|------------|
| Envelope | Insulation before cover |
| Air barrier | Continuity check |
| Mechanical | Equipment verification |
| Electrical | Lighting controls |
| Final | Blower door (if req'd) |
