CS25 Energy Code Feasibility Study in Walpole, Massachusetts
Energy code feasibility study for a 95-unit Multifamily in Massachusetts. Compares multiple design paths. Recommended: lowest-cost compliant path. View full study.
- Study Type
- Energy Code Feasibility Study
- State
- Massachusetts
- Units
- 95
- Building Type
- Multifamily
- Fuel Type
- All-Electric
Goal
This report is designed to help project teams identify the most cost-effective approach to energy code compliance. The costs shown reflect only the efficiency measures required for each energy code path, not total construction costs, allowing a clear comparison of true performance and incentive differences between paths.
All estimates are grounded in real Massachusetts bid data, the Mass Save Energy Code Study, and RSMeans regional pricing benchmarks. This study provides a reliable framework for aligning incentives and assembly design, with all recommendations confirmed through detailed energy modeling and local code requirement documentation.
Project
- Walpole, MA 02081
- 95 Units | 103,680 sqft
- 4 stories | 3 residential over commercial space..
- New Construction | Mixed-Use | All Electric
Code & Paths
Stretch Energy Code
Stretch Code - HERS (BASE)
- Action: Swap the ERV from Panasonic FV-10VE2 (min 53 CFM) to Panasonic FV-11ES1 (adjustable 36 - 110 CFM).
- Reason: The current FV-10VE2 is oversized by 30 CFM for smaller units. The FV-11ES1 allows exact CFM settings, saving energy.
- Result: Decreases HERS score by 2 points (fixing the 1-point deficit + buffer) at no additional cost.
Stretch Code - HERS (BASEv2)
- Action: Increase continuous roof insulation from R-6.5 to R-16.5.
- Reason: This addresses the 1-point deficit needed for code compliance.
- Result: Effective, but slightly more expensive than the BASE option. Only use if the recommended ERV swap is impossible.
Stretch Code - HERS (BASEv3)
- Action: Decrease minimum U-Value for all windows/doors from U-0.30 to U-0.28.
- Reason: Addresses the 1-point deficit.
- Result: The cost increase is greater than both the ERV swap and the roof insulation upgrade.
Stretch Code - HERS (ESTAR - Recommended Path)
- Action: Submit for ENERGY STAR MFNC certification using the exact same specifications as the BASE path.
- Reason: The BASE path automatically meets these requirements, so this option is included simply to highlight the financial benefit.
- Result: Increases incentives by $750 per unit with zero changes to construction cost or scope.
Stretch Code - PHIUS
- Action: Pursue the alternative PHIUS (Passive House) compliance pathway.
- Reason: Included for study comparison only.
- Result: Construction and soft costs skyrocket. The available incentives do not cover the huge cost increase.
Incentives
- Stretch Code - HERS (BASE)
- Mass Save Multifamily High Rise New Construction - Base Tier: $95,000.
- Mass Save Passive House Feasibility Study - $5,000.
- Mass Save Passive House Energy Model - $20,000.
- Mass Save In-Unit Heat Pump Water Heater - $23,750.
- DOER Alternative Energy Certificates - $28,500 - $47,500 (depends on market at time of AEC sale).
- Stretch Code - HERS (BASEv2)
- Mass Save Multifamily High Rise New Construction - Base Tier: $95,000.
- Mass Save Passive House Feasibility Study - $5,000.
- Mass Save Passive House Energy Model - $20,000.
- Mass Save In-Unit Heat Pump Water Heater - $23,750.
- DOER Alternative Energy Certificates - $28,500 - $47,500 (depends on market at time of AEC sale).
- Stretch Code - HERS (BASEv3)
- Mass Save Multifamily High Rise New Construction - Base Tier: $95,000.
- Mass Save Passive House Feasibility Study - $5,000.
- Mass Save Passive House Energy Model - $20,000.
- Mass Save In-Unit Heat Pump Water Heater - $23,750.
- DOER Alternative Energy Certificates - $28,500 - $47,500 (depends on market at time of AEC sale).
- Stretch Code - HERS (ESTAR)
- Mass Save Multifamily High Rise New Construction - Energy Star Tier: $166,250.
- Mass Save Passive House Feasibility Study - $5,000.
- Mass Save Passive House Energy Model - $20,000.
- Mass Save In-Unit Heat Pump Water Heater - $23,750.
- DOER Alternative Energy Certificates - $28,500 - $47,500 (depends on market at time of AEC sale).
- Stretch Code - PHIUS
- Mass Save Multifamily High Rise New Construction - PHIUS Tier: $356,250.
- Mass Save Passive House Feasibility Study - $5,000.
- Mass Save Passive House Energy Model - $20,000.
- DOER Alternative Energy Certificates - $28,500 - $47,500 (depends on market at time of AEC sale).
- Other Incentives That Aren’t Worth It:
- ENERGY STAR Next Gen: This option requires pursuing ENERGY STAR NextGen Certification, which requires tighter air sealing targets of ≤1.5 ACH50, higher insulation quality, upgraded equipment specifications, expanded documentation, and third party verification. For a 95 unit multifamily building, the incremental construction and certification cost to reliably meet ENERGY STAR NextGen requirements commonly ranges from $95,000–$190,000+, excluding internal project management time. In comparison, the available incentive of $250/unit equates to $23,750 for the full building, which does not materially offset the added cost, making this pathway financially unattractive.
- DOE Zero Ready: This requires an indoor air plus and DOE Zero Ready certification which adds soft costs and complexity. Additionally it adds hard costs from requiring more efficient windows & hot water recirculators, the $500 incentive doesn’t come close to offsetting these increased costs.
- High-rise Whole Building Infiltration Testing: This option requires achieving significantly tighter whole building air leakage targets of 0.4 CFM/sf @ 75 Pa or 0.25 CFM/sf @ 75 Pa, which typically requires enhanced air sealing details, increased labor, added trade coordination, and expanded QA beyond standard code practice. For a 95 unit multifamily building, the incremental construction cost to reliably achieve these targets is commonly on the order of $95,000 - $237,500 for 0.4 CFM/sf @ 75 Pa and $237,500 - $475,000+ for 0.25 CFM/sf @ 75 Pa, excluding testing. Even before adding the ASTM E779 whole building infiltration testing cost, these incremental air sealing costs materially exceed the available incentives of $28,500 at $300/unit and $38,000 at $400/unit, making this pathway financially unattractive.
- Induction Cooktop: Cost about $400 more than standard electric ranges, and with only a $250 incentive, you’d lose roughly $150, worth it only for personal preference, not savings.
- Split Heat Pump Water Heater: Cost about $3,000, roughly $1,200 more than a standard $1,800 unit, but with only a $250 incentive, the net loss is about $950.
Net Cost Summary
Path | Total Cost $/sf | Total Incentives $/sf | Net $/sf |
|---|---|---|---|
BASE | $45.59 | $1.66 | $43.93 |
BASEv2 | $46.04 | $1.66 | $44.38 |
BASEv3 | $46.12 | $1.66 | $44.46 |
ESTAR | $46.04 | $2.35 | $43.69 |
PHIUS | $61.92 | $3.95 | $57.96 |
Envelope
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Exterior Walls | BASE | 2×6 R-21 batt + R-5 continuous insulation. | $2.55 | $0.00 | $2.55 |
BASEv2 | 2×6 R-21 batt + R-5 continuous insulation. | $2.55 | $0.00 | $2.55 | |
BASEv3 | 2×6 R-21 batt + R-5 continuous insulation. | $2.55 | $0.00 | $2.55 | |
ESTAR | 2×6 R-21 batt + R-5 continuous insulation. | $2.55 | $0.00 | $2.55 | |
PHIUS | 2×6 R-23 batt + R-25 continuous insulation. | $4.95 | $0.00 | $4.95 | |
Roof | BASE | R-49 batt + R-6.5 continuous insulation. | $1.63 | $0.00 | $1.63 |
BASEv2 | R-49 batt + R-16.5 continuous insulation. | $1.88 | $0.00 | $1.88 | |
BASEv3 | R-49 batt + R-6.5 continuous insulation. | $1.63 | $0.00 | $1.63 | |
ESTAR | R-49 batt + R-6.5 continuous insulation. | $1.88 | $0.00 | $1.88 | |
PHIUS | R-60 batt + R-30 continuous insulation. | $3.00 | $0.00 | $3.00 | |
Exterior Floor | BASE | R-30 Batt Insulation | $0.63 | $0.00 | $0.63 |
BASEv2 | R-30 Batt Insulation | $0.63 | $0.00 | $0.63 | |
BASEv3 | R-30 Batt Insulation | $0.63 | $0.00 | $0.63 | |
ESTAR | R-30 Batt Insulation | $0.63 | $0.00 | $0.63 | |
PHIUS | R-60 Batt Insulation | $1.13 | $0.00 | $1.13 | |
Windows | BASE | U-0.30 / SHGC 0.30-0.40 | $3.90 | $0.00 | $3.90 |
BASEv2 | U-0.30 / SHGC 0.30-0.40 | $3.90 | $0.00 | $3.90 | |
BASEv3 | U-0.28 / SHGC 0.30-0.40 | $4.20 | $0.00 | $4.20 | |
ESTAR | U-0.30 / SHGC 0.30-0.40 | $3.90 | $0.00 | $3.90 | |
PHIUS | U-0.15 / SHGC 0.30-0.40 | $6.60 | $0.00 | $6.60 | |
Doors | BASE | Glazed: U-0.30 / SHGC 0.30-0.40 Opaque: U-0.21 (R-4.75); | $0.25 | $0.00 | $0.25 |
BASEv2 | Glazed: U-0.30 / SHGC 0.30-0.40 Opaque: U-0.21 (R-4.75); | $0.25 | $0.00 | $0.25 | |
BASEv3 | Glazed: U-0.28 / SHGC 0.30-0.40 Opaque: U-0.21 (R-4.75); | $0.28 | $0.00 | $0.28 | |
ESTAR | Glazed: U-0.30 / SHGC 0.30-0.40 Opaque: U-0.21 (R-4.75); | $0.25 | $0.00 | $0.25 | |
PHIUS | Glazed: U-0.15 / SHGC 0.30-0.40 Opaque: U-0.14 (R-7); | $0.48 | $0.00 | $0.48 | |
Air Sealing | BASE | Plan & QA to hit ≤3 ACH50 (≤0.22 CFM/ft² shell area) | $0.35 | $0.00 | $0.35 |
BASEv2 | Plan & QA to hit ≤3 ACH50 (≤0.22 CFM/ft² shell area) | $0.35 | $0.00 | $0.35 | |
BASEv3 | Plan & QA to hit ≤3 ACH50 (≤0.22 CFM/ft² shell area) | $0.35 | $0.00 | $0.35 | |
ESTAR | Plan & QA to hit ≤3 ACH50 (≤0.22 CFM/ft² shell area) | $0.35 | $0.00 | $0.35 | |
PHIUS | Plan & QA to hit ≤0.45 ACH50 (≤0.05 CFM/ft² shell area) | $2.50 | $0.00 | $2.50 |
Mechanical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
HVAC | BASE | Studio & 1Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 19.3 HSPF2 ≥ 10 (Product Rec) 2Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 20 HSPF2 ≥ 10 (Product Rec) 2 Story 2 Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 (Product Rec) | $22.00 | $0.27 | $21.73 |
BASEv2 | Studio & 1Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 19.3 HSPF2 ≥ 10 2Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 20 HSPF2 ≥ 10 2 Story 2 Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 | $22.00 | $0.27 | $21.73 | |
BASEv3 | Studio & 1Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 19.3 HSPF2 ≥ 10 2Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 20 HSPF2 ≥ 10 2 Story 2 Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 | $22.00 | $0.27 | $21.73 | |
ESTAR | Studio & 1Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 19.3 HSPF2 ≥ 10 2Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 20 HSPF2 ≥ 10 2 Story 2 Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 | $22.00 | $0.27 | $21.73 | |
PHIUS | Studio & 1Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 19.3 HSPF2 ≥ 10 2Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 20 HSPF2 ≥ 10 2 Story 2 Bed: Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 | $22.00 | $0.27 | $21.73 | |
Mechanical Ventilation | BASE | ERV: 30-60 CFM, ≤ 1.9 CFM per Watt, 79-92% recovery; All Units; Panasonic FV-11ES1; (Product Rec) | $1.60 | $0.00 | $1.60 |
BASEv2 | ERV: 30-60 CFM, ≤ 1.8 CFM per Watt, 77 - 83% recovery; All Units: Panasonic FV-10VE2; | $1.60 | $0.00 | $1.60 | |
BASEv3 | ERV: 30-60 CFM, ≤ 1.8 CFM per Watt, 77 - 83% recovery; All Units: Panasonic FV-10VE2; | $1.60 | $0.00 | $1.60 | |
ESTAR | ERV: 30-60 CFM, ≤ 1.9 CFM per Watt, 79-92% recovery; All Units; Panasonic FV-11ES1; | $1.60 | $0.00 | $1.60 | |
PHIUS | ERV: 30-60 CFM, ≤ 0.8 CFM per Watt, 80% recovery, PHIUS Certified; | $2.80 | $0.00 | $2.80 | |
Local Mechanical Exhaust | BASE | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones, exhaust directly outdoors; ENERGY STAR certified. Kitchen (s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH based on kitchen volume & ≤ 1.0 sone, exhaust directly outdoors; ENERGY STAR certified. (Product Rec) | $0.50 | $0.00 | $0.50 |
BASEv2 | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones, exhaust directly outdoors; ENERGY STAR certified. Kitchen (s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH based on kitchen volume & ≤ 1.0 sone, exhaust directly outdoors; ENERGY STAR certified. | $0.50 | $0.00 | $0.50 | |
BASEv3 | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones, exhaust directly outdoors; ENERGY STAR certified. Kitchen (s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH based on kitchen volume & ≤ 1.0 sone, exhaust directly outdoors; ENERGY STAR certified. | $0.50 | $0.00 | $0.50 | |
ESTAR | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones, exhaust directly outdoors; ENERGY STAR certified. Kitchen (s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH based on kitchen volume & ≤ 1.0 sone, exhaust directly outdoors; ENERGY STAR certified. | $0.50 | $0.00 | $0.50 | |
PHIUS | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones, exhaust directly outdoors; ENERGY STAR certified. Kitchen (s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH based on kitchen volume & ≤ 1.0 sone, exhaust directly outdoors; ENERGY STAR certified. | $0.50 | $0.00 | $0.50 | |
Thermostats | BASE | N/A | $0.00 | $0.00 | $0.00 |
BASEv2 | N/A | $0.00 | $0.00 | $0.00 | |
BASEv3 | N/A | $0.00 | $0.00 | $0.00 | |
ESTAR | N/A | $0.00 | $0.00 | $0.00 | |
PHIUS | Wi-Fi thermostat | $0.15 | $0.00 | $0.15 |
Plumbing & Appliances
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
DHW | BASE | HPWH In Unit (UEF ≥3.83) (Product Rec) | $2.25 | $0.23 | $2.02 |
BASEv2 | HPWH In Unit (UEF ≥3.83) | $2.25 | $0.23 | $2.02 | |
BASEv3 | HPWH In Unit (UEF ≥3.83) | $2.25 | $0.23 | $2.02 | |
ESTAR | HPWH In Unit (UEF ≥3.83) | $2.25 | $0.23 | $2.02 | |
PHIUS | HPWH In Garage (UEF ≥3.83) & recirculation system. | $4.50 | $0.00 | $4.50 | |
Hot Water Piping | BASE | Hot water pipes insulated to R-3. | $0.50 | $0.00 | $0.50 |
BASEv2 | Hot water pipes insulated to R-3. | $0.50 | $0.00 | $0.50 | |
BASEv3 | Hot water pipes insulated to R-3. | $0.50 | $0.00 | $0.50 | |
ESTAR | Hot water pipes insulated to R-3. | $0.50 | $0.00 | $0.50 | |
PHIUS | Hot water pipes insulated to R-6. | $0.75 | $0.00 | $0.75 | |
Water Fixtures | BASE | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) (Kitchen-Product Rec) (Bathroom-Product Rec) (Shower-Product Rec) | $1.00 | $0.00 | $1.00 |
BASEv2 | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) | $1.00 | $0.00 | $1.00 | |
BASEv3 | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) | $1.00 | $0.00 | $1.00 | |
ESTAR | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) | $1.00 | $0.00 | $1.00 | |
PHIUS | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) | $1.00 | $0.00 | $1.00 | |
Appliances | BASE | ENERGY STAR Certified All Electric Appliances (Refrigerator) (Dishwasher) (Washer/Dryer) | $3.50 | $0.00 | $3.50 |
BASEv2 | ENERGY STAR Certified All Electric Appliances | $3.50 | $0.00 | $3.50 | |
BASEv3 | ENERGY STAR Certified All Electric Appliances | $3.50 | $0.00 | $3.50 | |
ESTAR | ENERGY STAR Certified All Electric Appliances | $3.50 | $0.00 | $3.50 | |
PHIUS | ENERGY STAR Certified All Electric Appliances | $3.50 | $0.00 | $3.50 |
Electrical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Lighting | BASE | 100% high-efficacy (LED) | $4.00 | $0.00 | $4.00 |
BASEv2 | 100% high-efficacy (LED) | $4.00 | $0.00 | $4.00 | |
BASEv3 | 100% high-efficacy (LED) | $4.00 | $0.00 | $4.00 | |
ESTAR | 100% high-efficacy (LED) | $4.00 | $0.00 | $4.00 | |
PHIUS | 100% high-efficacy (LED) | $4.00 | $0.00 | $4.00 | |
Solar Ready | BASE | N/A | $0.00 | $0.00 | $0.00 |
BASEv2 | N/A | $0.00 | $0.00 | $0.00 | |
BASEv3 | N/A | $0.00 | $0.00 | $0.00 | |
ESTAR | N/A | $0.00 | $0.00 | $0.00 | |
PHIUS | Reserve 50% roof area for 'Future Solar System', space for a dual-pole breaker in the main electrical panel labeled 'Future Solar,' and a conduit run and capped from the roof zone to the electrical panel. | $0.10 | $0.00 | $0.10 | |
EV Ready | BASE | Provide powered 208/240 V EV receptacle(s) for not less than 20% of parking spaces, each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.75 | $0.00 | $0.75 |
BASEv2 | Provide powered 208/240 V EV receptacle(s) for not less than 20% of parking spaces, each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.75 | $0.00 | $0.75 | |
BASEv3 | Provide powered 208/240 V EV receptacle(s) for not less than 20% of parking spaces, each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.75 | $0.00 | $0.75 | |
ESTAR | Provide powered 208/240 V EV receptacle(s) for not less than 20% of parking spaces, each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.75 | $0.00 | $0.75 | |
PHIUS | Provide powered 208/240 V EV receptacle(s) for not less than 20% of parking spaces, each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.75 | $0.00 | $0.75 |
Soft Costs
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Modeling / Program Admin / Commissioning | BASE | Energy model, 2021 IECC checklists and incentive documentation. | $0.38 | $1.16 | -$0.77 |
BASEv2 | Energy model, 2021 IECC checklists and incentive documentation. | $0.38 | $1.16 | -$0.77 | |
BASEv3 | Energy model, 2021 IECC checklists and incentive documentation. | $0.38 | $1.16 | -$0.77 | |
ESTAR | ESTAR energy model, ENERGY STAR MFNC checklists, 2021 IECC checklist and incentive documentation. | $0.38 | $1.84 | -$1.46 | |
PHIUS | WUFI model, THERM (Thermal Bridge) Modeling, DHW pipe run calculations, Integrated pest management plan, Low VOC adhesives & sealants, PHIUS checklists, ZERH checklists, Indoor Air Plus checklists, ESTAR energy model, ENERGY STAR SFNH checklists, 2021 IECC checklist and incentive documentation. | $3.21 | $3.68 | -$0.47 | |
Testing & Verification | BASE | Blower Door Test, Mechanical Ventilation Testing, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 |
BASEv2 | Blower Door Test, Mechanical Ventilation Testing, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 | |
BASEv3 | Blower Door Test, Mechanical Ventilation Testing, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 | |
ESTAR | Blower Door Test, Mechanical Ventilation Testing, Room Balancing, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 | |
PHIUS | Blower Door Test, Mechanical Ventilation Testing, Room Balancing, Hot Water Delivery Test, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 |