CS27 Energy Code Feasibility Study in Millis, Massachusetts
Energy code feasibility study for a 28-unit 2-Story Townhomes with basements. in Massachusetts. Compares multiple design paths. Recommended: lowest-cost compliant path. View full study.
- Study Type
- Energy Code Feasibility Study
- State
- Massachusetts
- Units
- 28
- Building Type
- 2-Story Townhomes with basements.
- 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
- Millis, MA 02054
- 28 Townhomes | 50,400 sqft
- 2-Story Townhomes with basements.
- New Construction | Stretch Code | All Electric OR Gas/Electric
Code & Paths
Stretch Energy Code
Stretch Energy Code - HERS (GAS): This path represents the traditional fossil-fuel approach but results in the highest net cost of $36.32/sf. Because it relies on gas mechanicals (98.5% AFUE furnace and tankless water heater), it is ineligible for Mass Save or AEC incentives, meaning the project must bear the full construction cost. Additionally, to compensate for the use of gas and still meet Stretch Code performance targets, this path requires a more expensive building envelope, including R-6 continuous exterior insulation and high-performance U-0.25 windows.
Stretch Energy Code - HERS (ELECTRIC): The all-electric path offers a significant cost reduction, bringing the net cost down to $28.68/sf. By utilizing high-efficiency ductless heat pumps and heat pump water heaters, the project can meet code with a less costly envelope (eliminating the continuous exterior insulation and allowing standard U-0.30 windows). These construction savings are further enhanced by substantial financial support, including the Mass Save Base Tier incentive of $210,000 and Alternative Energy Certificates.
Stretch Energy Code - HERS (ESTAR): This is the most cost-effective option for the project, delivering the lowest net cost of $25.87/sf. While this path requires slightly higher standards than the standard electric path, specifically tighter air sealing (1.5 ACH50) and increased floor insulation, these costs are overwhelmingly offset by the incentives. By achieving Energy Star certification, the project qualifies for the top-tier Mass Save incentive of $420,000, making this the clear financial winner despite the rigorous verification requirements.
Incentives
- Stretch Code - HERS (GAS)
- None Available.
- Stretch Code - HERS (ELECTRIC)
- Mass Save Single Family New Construction - Base Tier: $210,000.
- DOER Alternative Energy Certificates - $8,400 - $16,800 (depends on market at time of AEC sale).
- Stretch Code - HERS (ESTAR)
- Mass Save Single Family New Construction - Energy Star Tier: $420,000.
- DOER Alternative Energy Certificates - $8,400 - $16,800 (depends on market at time of AEC sale).
- Other Incentives That Aren’t Worth It:
- 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.
- 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 |
|---|---|---|---|
GAS | $36.32 | $0.00 | $36.32 |
ELECTRIC | $33.01 | $4.33 | $28.68 |
ESTAR | $34.37 | $8.50 | $25.87 |
Envelope
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Exterior Walls | GAS | 2×6 R-21 batt + R-6 continuous insulation. | $3.80 | $0.00 | $3.80 |
ELECTRIC | 2×6 R-21 batt insulation. | $1.55 | $0.00 | $1.55 | |
ESTAR | 2×6 R-21 batt insulation. | $1.55 | $0.00 | $1.55 | |
Floor Over Unconditioned Space | GAS | R-60 batt insulation. | $1.50 | $0.00 | $1.50 |
ELECTRIC | R-30 batt insulation. | $0.85 | $0.00 | $0.85 | |
ESTAR | R-49 batt insulation. | $1.25 | $0.00 | $1.25 | |
Rim Joists | GAS | R-21 Spray Foam (Closed Cell) | $1.00 | $0.00 | $1.00 |
ELECTRIC | R-21 Spray Foam (Closed Cell) | $1.00 | $0.00 | $1.00 | |
ESTAR | R-21 Spray Foam (Closed Cell) | $1.00 | $0.00 | $1.00 | |
Roof | GAS | R-60 blown loose fill cellulose insulation. | $1.35 | $0.00 | $1.35 |
ELECTRIC | R-49 blown loose fill cellulose insulation. | $1.05 | $0.00 | $1.05 | |
ESTAR | R-60 blown loose fill cellulose insulation. | $1.35 | $0.00 | $1.35 | |
Windows | GAS | U-0.25 / SHGC 0.30-0.40 | $5.50 | $0.00 | $5.50 |
ELECTRIC | U-0.30 / SHGC 0.30-0.40 | $4.00 | $0.00 | $4.00 | |
ESTAR | U-0.30 / SHGC 0.30-0.40 | $4.00 | $0.00 | $4.00 | |
Doors | GAS | Glazed: U-0.25 / SHGC 0.30-0.40; Opaque: U-0.21 (R-4.75); | $0.40 | $0.00 | $0.40 |
ELECTRIC | Glazed: U-0.30 / SHGC 0.30-0.40; Opaque: U-0.21 (R-4.75); | $0.30 | $0.00 | $0.30 | |
ESTAR | Glazed: U-0.30 / SHGC 0.30-0.40; Opaque: U-0.21 (R-4.75); | $0.30 | $0.00 | $0.30 | |
Air Sealing | GAS | Units: ≤3 ACH50; | $0.60 | $0.00 | $0.60 |
ELECTRIC | Units: ≤3 ACH50; | $0.60 | $0.00 | $0.60 | |
ESTAR | Units: ≤1.5 ACH50; | $1.20 | $0.00 | $1.20 |
Mechanical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
HVAC | GAS | Ducted Gas Furnace (AFUE 98.5%) (Product Rec) & Split Air Conditioner (SEER2 14.5) (Product Rec Outdoor Unit) (Product Rec Indoor Unit) | $7.00 | $0.00 | $7.00 |
ELECTRIC | Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 (42kBtu/h) (Product Rec) | $8.50 | $0.17 | $8.33 | |
ESTAR | Ductless, cold-climate, ENERGY STAR certified, split heat pump, SEER2 ≥ 23 HSPF2 ≥ 12 (42kBtu/h) (Product Rec) | $8.50 | $0.17 | $8.33 | |
Mechanical Ventilation | GAS | ERV: 30-70 CFM, ≤ 1.9 CFM per Watt, 79-92% recovery; All Units; (Product Rec) | $1.70 | $0.00 | $1.70 |
ELECTRIC | ERV: 30-70 CFM, ≤ 1.9 CFM per Watt, 79-92% recovery; All Units; (Product Rec) | $1.70 | $0.00 | $1.70 | |
ESTAR | ERV: 30-90 CFM, ≤ 1.9 CFM per Watt, 79-92% recovery; All Units; (Product Rec) | $1.70 | $0.00 | $1.70 | |
Local Mechanical Exhaust | GAS | 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) | $0.45 | $0.00 | $0.45 |
ELECTRIC | 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) | $0.45 | $0.00 | $0.45 | |
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. (Product Rec) | $0.45 | $0.00 | $0.45 | |
Thermostats | GAS | N/A | $0.00 | $0.00 | $0.00 |
ELECTRIC | N/A | $0.00 | $0.00 | $0.00 | |
ESTAR | N/A | $0.00 | $0.00 | $0.00 |
Plumbing & Appliances
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
DHW | GAS | Tankless Gas Water Heater In Garage (UEF ≥0.96) (Product Rec) | $2.50 | $0.00 | $2.50 |
ELECTRIC | HPWH In Garage (UEF ≥3.83) (Product Rec) | $2.80 | $0.00 | $2.80 | |
ESTAR | HPWH In Garage (UEF ≥3.83) (Product Rec) | $2.80 | $0.00 | $2.80 | |
Hot Water Piping | GAS | Hot water pipes insulated to R-3. | $0.20 | $0.00 | $0.20 |
ELECTRIC | Hot water pipes insulated to R-3. | $0.20 | $0.00 | $0.20 | |
ESTAR | Hot water pipes insulated to R-3. | $0.20 | $0.00 | $0.20 | |
Water Fixtures | GAS | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) (Kitchen-Product Rec) (Bathroom-Product Rec) (Shower-Product Rec) | $2.25 | $0.00 | $2.25 |
ELECTRIC | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) (Kitchen-Product Rec) (Bathroom-Product Rec) (Shower-Product Rec) | $2.25 | $0.00 | $2.25 | |
ESTAR | Watersense certified fixtures (Lavatory: ≤1.5 GPM, Shower: ≤2.0 GPM) (Kitchen-Product Rec) (Bathroom-Product Rec) (Shower-Product Rec) | $2.25 | $0.00 | $2.25 | |
Appliances | GAS | ENERGY STAR Certified All Electric Appliances (Refrigerator) (Dishwasher) (Washer) (Gas Dryer) (Gas Stove) | $2.50 | $0.00 | $2.50 |
ELECTRIC | Standard Appliances | $2.25 | $0.00 | $2.25 | |
ESTAR | Standard Appliances | $2.25 | $0.00 | $2.25 |
Electrical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Lighting | GAS | 100% high-efficacy (LED) | $4.50 | $0.00 | $4.50 |
ELECTRIC | 100% high-efficacy (LED) | $4.50 | $0.00 | $4.50 | |
ESTAR | 100% high-efficacy (LED) | $4.50 | $0.00 | $4.50 | |
Solar Ready | GAS | N/A | $0.00 | $0.00 | $0.00 |
ELECTRIC | N/A | $0.00 | $0.00 | $0.00 | |
ESTAR | N/A | $0.00 | $0.00 | $0.00 | |
EV Ready | GAS | Provide powered 208/240 V EV receptacle(s) each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.45 | $0.00 | $0.45 |
ELECTRIC | Provide powered 208/240 V EV receptacle(s) each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.45 | $0.00 | $0.45 | |
ESTAR | Provide powered 208/240 V EV receptacle(s) each served by a dedicated ≥40 A circuit labeled “EV Charging.” | $0.45 | $0.00 | $0.45 |
Soft Costs
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf |
|---|---|---|---|---|---|
Modeling / Program Admin / Commissioning | GAS | Energy model, 2021 IECC checklists and incentive documentation. | $0.62 | $0.00 | $0.62 |
ELECTRIC | Energy model, 2021 IECC checklists and incentive documentation. | $0.56 | $4.17 | -$3.60 | |
ESTAR | ELECTRIC energy model, ENERGY STAR SFNH checklists, 2021 IECC checklist and incentive documentation. | $0.62 | $8.33 | -$7.71 | |
Testing & Verification | GAS | Blower Door Test, Duct Test Total, Mechanical Ventilation Testing, Predrywall & Final Inspection. | $0.00 | $0.00 | $0.00 |
ELECTRIC | Blower Door Test, Duct Test Total, 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 |