CS67 Energy Code Feasibility Study in Shrewsbury, Massachusetts
Energy code feasibility study for a 250-unit Multifamily in Massachusetts. Compares multiple design paths. Recommended: HPWH (All-Electric). View full study.
- Study Type
- Energy Code Feasibility Study
- State
- Massachusetts
- Units
- 250
- Building Type
- Multifamily
- Fuel Type
- All-Electric
- Recommended Path
- HPWH (All-Electric)
Goal
To find the most cost-effective compliance path, this report isolates energy code related costs from total construction. We use real bid data from vendors & clients to create a reliable framework for aligning incentives and design, with all recommendations confirmed by detailed energy modeling.
Project
- Shrewsbury, MA
- 2 Buildings | 250 Units | 225,250 SF Conditioned
- New Construction | Multifamily Mixed-Use | 5 stories, 250 residential units (Building A 130, Building B 120) plus 12,000 SF commercial
- All-Electric | Stretch Code | HERS ≤ 45 | ESTAR MFNC v1.2
- Mixed Fuel | Stretch Code | HERS ≤ 42 | ESTAR MFNC v1.2
Overview
Read This: This report compares different ways you can build the project and meet energy code, looking at both cost and incentives, with the ultimate goal as finding the most affordable path.
- The overview outlines the key differences between each of the paths we show in this report and why we recommend the one we picked over the others.
- The recommended design section is where we share the requirements and incentives for the path we think is best based on affordability.
- The path comparison section shows the detailed requirements and incentives for each path we compared, basically showing our work if you want to dig in.
Path Summaries
All three paths meet Massachusetts Stretch energy code and are modeled to pass on a lean margin, so the choice between them comes down to cost and constructability, not compliance.
HPWH (All-Electric): Recommended
Recommended at $41.70/sf net, the lowest cost of the three and the baseline the other two are measured against. It keeps the project fully electric, which aligns with the direction Massachusetts energy code is heading. It is also the most involved of the three to build, and that is the tradeoff you accept for the lowest cost.
NO CI (All-Electric): Alternative (Builder-Friendly)
Alternative at $41.87/sf net, about $0.17/sf more than HPWH, and the fastest of the three to build. It carries the same all-electric code alignment, and that $0.17/sf is a rounding error against what the schedule costs. Pick it when speed on site matters more than the last dollar per square foot, because this is a genuinely close call with HPWH.
GAS (Mixed-Fuel): Not Recommended
Not recommended at $45.34/sf net, about $3.64/sf more than HPWH, and the most labor-intensive of the three to build. Mixed-fuel construction runs against the direction Massachusetts energy code is heading. The only reason to choose it is a market that specifically demands gas service.
Path Cost Comparison
Code Path
Permit / Certificate of Occupancy Requirements
High Rise Buildings
Recommended Design
This section outlines the design requirements, product recommendations, and incentives for the design that we believe will be the most affordable path to meeting energy code.
Recommended Design - Incentives
Incentives Available: $0 - $395,000
- SELCO Commercial Heat Pump Rebate ($0 - $20,000) (Program Breakdown): You get this rebate for installing air source heat pumps in a building served by SELCO, Shrewsbury's municipal electric utility. Shrewsbury does not pay into the Mass Save charge, so SELCO runs its own program in its place, and new construction qualifies for this one. It pays $750 per ton of heating capacity and caps at $20,000 per customer or developer, so a project of this size reaches the cap on heating capacity alone. The rebate comes in the form of a check after the equipment is installed and verified.
- IMPORTANT: SELCO has to pre-approve the rebate in writing before any work begins. Starting the work first gives it up entirely, so the application belongs in the pre-construction schedule.
- Risks: SELCO funds only a handful of projects a year out of a limited budget, first come and first serve, so this is worth pursuing as upside rather than carrying it as a budgeted line. The $20,000 cap is written per customer or developer, so a second building under a related entity is unlikely to claim it twice. Buildings that take natural gas service from Eversource are not eligible for this program at all.
- DOER Alternative Energy Credits ($0 - $375,000) (Program Breakdown): This rebate is received for installing APS eligible air source heat pumps (click here for the list). There is an extensive process to get this incentive. It comes in the form of a check approximately 6-12 months after the heat pumps are installed and fully operational.
- IMPORTANT: Although an estimate is provided, this incentive can vary widely typically between $300-1,500 per heat pump. It's based on expected kWh usage of the system as well as the market value of the alternative energy credits when sold.
- Risks: Massachusetts is rewriting this program right now. The House bill would stop the state from accepting new applications on January 1, 2028, the Senate version leaves heat pumps out of that cutoff, and the two are in conference. The application needs the equipment installed and operating, so a project that will not reach that point before the deadline should treat this as upside rather than a budgeted line.
Recommended Design - Units
Item | Detailed Specifications |
|---|---|
Exterior Walls | R-21 fiberglass batts in a 2x6 @ 16" o.c. cavity with R-5 continuous insulation; ZIP sheathing. R-38 cavity insulation may be used in place of the R-21 batt + R-5 continuous insulation; the cost of that alternative is not considered in this study. |
Below Grade Walls | N/A |
Corridor Walls | N/A |
Slab | R-10 fully insulated slab. |
Floor Over Unconditioned Space | N/A |
Floor Over Garage | N/A |
Floor Over Podium | N/A |
Rim Joists | 3" closed-cell spray foam (R-21) at floor transitions. |
Roof | Sealed (unvented) roof: R-19 cavity (3" closed-cell spray foam) with R-30 continuous insulation at the roof deck. |
Windows & Glass Doors | Vinyl double-pane low-E argon; U-0.30 / SHGC 0.30. |
Doors | Opaque: insulated entry door, R-4.75. |
Air Sealing | ≤ 0.30 CFM50 per sqft of enclosure (compartmentalization); tested. |
HVAC | Ducted cold-climate heat pump; HSPF2 9.0 to 9.5; SEER2 18.5 to 19.5; ENERGY STAR Cold Climate; ducted air handler with outdoor condenser; 1.5 ton (studio & 1BR), 2 ton (2BR). |
Ductwork | Supply and return ducts in conditioned space; R-6. |
Duct Sealing | The greater of 8 CFM25 per 100 sqft of conditioned floor area or 80 CFM25 to outside. |
HVAC Grading | N/A |
Mechanical Ventilation | In-unit ERV; 40 CFM (studio & 1BR), 60 CFM (2BR); 87% SRE. |
Local Mechanical Exhaust | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones. Kitchen(s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH. Both: exhaust directly outdoors, ENERGY STAR certified, utilize ERV. |
Thermostats | Programmable smart thermostat. |
DHW | Heat pump water heater; 50 gal (studio & 1BR) / 65 gal (2BR); UEF 3.5; located in a conditioned corridor. |
DHW Piping | R-3 insulation on all hot water lines; trunk-to-fixture length ≤ 35 ft (studio & 1BR), ≤ 40 ft (2BR), plus the corridor-to-unit run; no recirculation. |
Water Fixtures | WaterSense certified low-flow: showerhead ≤ 1.8 GPM; lavatory faucet ≤ 1.5 GPM; kitchen faucet ≤ 1.8 GPM. |
Refrigerator | ≤ 450 kWh/yr (studio & 1BR) / ≤ 550 kWh/yr (2BR); ENERGY STAR. |
Dishwasher | ≤ 269 kWh/yr; ENERGY STAR; standard size; electric. |
Clothes Washer | Front-load; IMEF 1.84; IWF 4.7; 141 kWh/yr; 5.0 cuft; ENERGY STAR; electric. |
Clothes Dryer | Electric; CEF 3.93; moisture-sensing controls; ENERGY STAR. |
Stove / Oven | Electric induction cooktop; convection oven. |
Lighting | 100% high-efficacy (LED). |
Solar Ready | Designated solar zone: contiguous area ≥ 40% of total horizontal roof area, free of obstructions, minimum 5 ft wide. Structural capacity for 5 PSF collateral dead load. Conduit pathways and reserved breaker space. |
EV Ready | EV-ready infrastructure for at least 20% of total parking. Branch circuit and termination for required spaces, rated at least 6.2 kVA per space. |
HPWH Ready | N/A |
Paperwork & Modeling | HERS/ERI energy model, 2021 IECC checklists, ENERGY STAR checklists, incentive documentation. |
Testing & Verification | Unit blower door test, total duct leakage test, mechanical ventilation testing, room balancing, pre-drywall and final inspection. |
Recommended Design - Common Areas & Clubhouse
Item | Common Areas (Residential Bldgs) | Clubhouse |
|---|---|---|
Exterior Walls | Wood-frame: R-13 + R-7.5 CI or R-20 + R-3.8 CI or R-30. Steel-frame: R-13 + R-7.5 CI (CI mandatory). | Same |
Below Grade Walls | R-7.5 continuous insulation. | Same |
Corridor Walls | Common area wall insulation governs; refer to Exterior Walls. | Same as clubhouse wall insulation. |
Slab | R-10 edge, extending 4 feet or 24 inches below grade (whichever is greater). | Same |
Floor Over Unconditioned Space | R-13 cavity with R-17 CI, or R-30 cavity only, or R-19 cavity with R-5 CI. | U-factor ≤ 0.033 per commercial assembly (R-13/R-17 equivalent). |
Floor Over Garage | R-13 cavity with R-17 CI, or R-30 cavity only, or R-19 cavity with R-5 CI. | U-factor ≤ 0.033 per commercial assembly (R-13/R-17 equivalent). |
Floor Over Podium | R-30 continuous insulation. | Same |
Rim Joists | Insulation and air barrier continuous through rim joint; seal with caulk or foam; match wall R-value above and below grade. | Same, continuous with wall assembly. |
Roof | R-30 continuous insulation at deck; or R-49 in attic with air barrier and Grade I insulation installation. | Same |
Windows & Glass Doors | Fixed U ≤ 0.30; operable U ≤ 0.30; SHGC ≤ 0.40. | Fixed U ≤ 0.30; operable U ≤ 0.32; SHGC ≤ 0.40. |
Doors | Glazed entrance U ≤ 0.60; opaque U ≤ 0.37. | Glazed entrance U ≤ 0.77; opaque U ≤ 0.37. |
Air Sealing | Continuous air barrier per residential air-barrier table; Grade I insulation install; penetrations, rough openings, and electrical boxes sealed; unit-to-corridor doors gasketed. Enclosed common spaces ≤ 1,500 sqft verified by inspection. | Continuous air barrier; whole-building blower door ≤ 0.35 CFM/sqft at 75 Pa. |
HVAC | Ducted split HP: SEER2 15.2 / HSPF2 7.8. Ductless: 16 / 8.2. Packaged: 15.2 / 7.7. PTAC/PTHP/room AC certified to ENERGY STAR. Manual J/S sizing. | Same, plus cold-climate HP (COP ≥ 1.75 at 5°F, no resistance except defrost); each cooling system ≤ 54 kBtu/h exemption, or add economizer. |
Ductwork | Distribute conditioned air to all occupied common spaces. Ducts and air-handler units located entirely within conditioned space. Design and test to standard duct-design and duct-leakage practice. | Distribute conditioned air to all spaces. Ducts and air-handler units located in conditioned space. Design and testing per commercial code standards. |
Duct Sealing | Per system, final test (at 25 Pa): 6 CFM per 100 sqft or 60 CFM (no return ducts); 8 CFM per 100 sqft or 80 CFM (1–2 return ducts); 12 CFM per 100 sqft or 120 CFM (3+ returns). Rough-in: 3/30, 4/40, or 6/60. All ducts and AHU in conditioned space. Tested. | Same final and rough-in targets. All ducts in conditioned space. |
HVAC Grading | N/A | Same |
Mechanical Ventilation | Outdoor air to all occupied common spaces: Lobby/Office 5 cfm/person + 0.06 cfm/sqft; Fitness 20 + 0.06; Corridor 0.06; Laundry 5 + 0.12. Installed at design airflow or above. Mandatory DCV for spaces over 500 sqft and over 25 people/1,000 sqft. Energy recovery (ERV, 70% sensible / 60% enthalpy) required for qualifying systems by runtime and outdoor-air fraction. | Same ventilation rates. Plus: demand control ventilation for spaces over 500 sqft with occupancy over 25 people/1,000 sqft. Energy recovery (ERV) required if: any system operates 8,000+ hrs/year with ≥ 10% outdoor air; or shorter-runtime systems above 10,000 cfm (10–20% OA), 8,000 cfm (20–30%), 2,750 cfm (30–40%), or any size at ≥ 40% OA. ERV: 70% sensible, 60% enthalpy minimum at design conditions. |
Local Mechanical Exhaust | Restrooms, laundry rooms, janitor closets, mechanical equipment rooms: exhaust ducted directly to outdoors and certified to ENERGY STAR. | Same |
Thermostats | Programmable, 5F setback | Same |
DHW | Point-of-use electric, UEF ≥ 0.93 | Same |
DHW Piping | R-3 (1.5 in. and smaller); R-4 (larger) | Same |
Water Fixtures | WaterSense: Lav 1.5 GPM; Toilet 1.28 GPF; Urinal 0.5 GPF | Same |
Refrigerator | N/A | ENERGY STAR certified; all-electric |
Dishwasher | N/A | ENERGY STAR certified; all-electric |
Clothes Washer | N/A | ENERGY STAR certified; all-electric |
Clothes Dryer | N/A | ENERGY STAR certified; all-electric |
Stove / Oven | N/A | ENERGY STAR certified; all-electric (no gas) |
Lighting | 100% LED. LPD (W/sqft): Corridor 0.41; Lobby 0.84; Office 0.74; Fitness 0.72; Laundry 0.53; Stair 0.49; Mech/Elec 0.43; Storage 0.38 | Same |
Lighting Controls | Occupancy sensors (corridors/stairs may dim to 50%); auto time switches; daylight controls where zone exceeds 100 W (primary sidelit), 300 W (sidelit), or 100 W (toplit) | Occupancy sensors; auto time switches; daylight controls where zone exceeds 100 W (primary sidelit), 300 W (sidelit), or 100 W (toplit) |
Solar Ready | Solar-ready zone per residential spec (40% roof zone, 5 PSF capacity, conduit + breaker space). | Same |
EV Ready | 20% of installed parking spaces: 40-amp 208/240V dedicated branch circuits, 9.6 kVA minimum; AC Level I substitution allowed at 3:1 ratio. | 10% if dedicated clubhouse-only parking lot; 40-amp 208/240V or equivalent ALMS |
HPWH Ready | N/A | Same |
Electric Readiness | N/A | Same |
Vestibules | Self-closing vestibule at public building entrances; exempt if building under 3,000 sqft, or for employee-only/mechanical room doors, dwelling unit doors, revolving doors, or air curtains. | Same |
Efficiency Credits | 15 credits required. Cold-climate heat pumps (COP ≥ 1.75 at 5°F, electric resistance prohibited except defrost) earn all 15 when meeting all space heating requirements. | Same |
Paperwork & Modeling | COMcheck for common-area envelope, lighting, and mechanical (commercial compliance) plus efficiency-credit documentation. ENERGY STAR workbook, checklists, and common-space HVAC supplement (mandatory). HERS submittals at permit and CO. | COMcheck envelope, lighting, and mechanical certificates. Efficiency-credit documentation. Ventilation calculations. Thermal bridge derating if >20,000 sqft. |
Testing & Verification | Ventilation balancing per design. Duct leakage testing at rough-in and final. HVAC functional testing by FT agent (mandatory). Lighting controls testing. Air barrier inspections. | Same, plus whole-building blower door test ≤ 0.35 CFM/sqft at 75 Pa. |
Exterior Wall (NO CI, GAS)
Exterior Wall (HPWH)
Slab (All Paths)
Rim Joist (NO CI, GAS)
Rim Joist (HPWH)
Roof (All Paths)
Path Comparison
This section shows the detailed requirements and incentives for each path we compared, basically showing our work of how we determined the recommended path is the most affordable way of meeting energy code compliance.
Path Comparison - Incentives
HPWH / NO CI: $0 - $395,000
- SELCO Commercial Heat Pump Rebate ($0 - $20,000) (Program Breakdown): You get this rebate for installing air source heat pumps in a building served by SELCO, Shrewsbury's municipal electric utility. Shrewsbury does not pay into the Mass Save charge, so SELCO runs its own program in its place, and new construction qualifies for this one. It pays $750 per ton of heating capacity and caps at $20,000 per customer or developer, so a project of this size reaches the cap on heating capacity alone. The rebate comes in the form of a check after the equipment is installed and verified.
- IMPORTANT: SELCO has to pre-approve the rebate in writing before any work begins. Starting the work first gives it up entirely, so the application belongs in the pre-construction schedule.
- Risks: SELCO funds only a handful of projects a year out of a limited budget, first come and first serve, so this is worth pursuing as upside rather than carrying it as a budgeted line. The $20,000 cap is written per customer or developer, so a second building under a related entity is unlikely to claim it twice. Buildings that take natural gas service from Eversource are not eligible for this program at all.
- DOER Alternative Energy Credits ($0 - $375,000) (Program Breakdown): This rebate is received for installing APS eligible air source heat pumps (click here for the list). There is an extensive process to get this incentive. It comes in the form of a check approximately 6-12 months after the heat pumps are installed and fully operational.
- IMPORTANT: Although an estimate is provided, this incentive can vary widely typically between $300-1,500 per heat pump. It's based on expected kWh usage of the system as well as the market value of the alternative energy credits when sold.
- Risks: Massachusetts is rewriting this program right now. The House bill would stop the state from accepting new applications on January 1, 2028, the Senate version leaves heat pumps out of that cutoff, and the two are in conference. The application needs the equipment installed and operating, so a project that will not reach that point before the deadline should treat this as upside rather than a budgeted line.
GAS: $0
- No Utility Program Available ($0) : Shrewsbury's electricity comes from SELCO, the town's municipal utility, which does not pay into the Mass Save charge, so Mass Save's new construction rebates are not available in Shrewsbury. SELCO runs its own heat pump rebate in place of Mass Save, and that program excludes any building taking natural gas service from Eversource. A mixed-fuel design sits outside both programs. The all-electric designs reach the SELCO program and the heat pump credits.
Path Comparison - Net Cost Summary
Path | Total Cost $/sf | Total Incentives $/sf | Net $/sf | OpEx Factor |
|---|---|---|---|---|
HPWH | $41.02 | $0.00 | $41.70 | 1.02 |
NO CI | $41.49 | $0.00 | $41.87 | 1.01 |
GAS | $44.53 | $0.00 | $45.34 | 1.02 |
Path Comparison - Envelope
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf | OpEx |
|---|---|---|---|---|---|---|
Exterior Walls | GAS | R-38 closed-cell spray foam in a 2x6 @ 16" o.c. cavity, no continuous insulation; ZIP sheathing. | $2.02 | $0.00 | $2.02 | 0.95 |
HPWH | R-21 fiberglass batts in a 2x6 @ 16" o.c. cavity with R-5 continuous insulation; ZIP sheathing. R-38 cavity insulation may be used in place of the R-21 batt + R-5 continuous insulation; the cost of that alternative is not considered in this study. | $1.53 | $0.00 | $1.53 | 0.90 | |
NO CI | R-38 closed-cell spray foam in a 2x6 @ 16" o.c. cavity, no continuous insulation; ZIP sheathing. | $2.02 | $0.00 | $2.02 | 0.95 | |
Below Grade Walls | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Corridor Walls | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Slab | GAS | R-10 fully insulated slab. | $0.49 | $0.00 | $0.49 | 0.90 |
HPWH | R-10 fully insulated slab. | $0.49 | $0.00 | $0.49 | 0.90 | |
NO CI | R-10 fully insulated slab. | $0.49 | $0.00 | $0.49 | 0.90 | |
Floor Over Unconditioned Space | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Floor Over Garage | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Floor Over Podium | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Rim Joists | GAS | 3" closed-cell spray foam (R-21) at floor transitions. | $0.20 | $0.00 | $0.20 | 0.95 |
HPWH | 3" closed-cell spray foam (R-21) at floor transitions. | $0.20 | $0.00 | $0.20 | 0.95 | |
NO CI | 3" closed-cell spray foam (R-21) at floor transitions. | $0.20 | $0.00 | $0.20 | 0.95 | |
Roof | GAS | Sealed (unvented) roof: R-19 cavity (3" closed-cell spray foam) with R-30 continuous insulation at the roof deck. | $1.26 | $0.00 | $1.26 | 1.10 |
HPWH | Sealed (unvented) roof: R-19 cavity (3" closed-cell spray foam) with R-30 continuous insulation at the roof deck. | $1.26 | $0.00 | $1.26 | 1.10 | |
NO CI | Sealed (unvented) roof: R-19 cavity (3" closed-cell spray foam) with R-30 continuous insulation at the roof deck. | $1.26 | $0.00 | $1.26 | 1.10 | |
Windows & Glass Doors | GAS | Vinyl double-pane low-E argon; U-0.27 / SHGC 0.30. | $2.07 | $0.00 | $2.07 | 1.00 |
HPWH | Vinyl double-pane low-E argon; U-0.30 / SHGC 0.30. | $1.98 | $0.00 | $1.98 | 1.00 | |
NO CI | Triple-pane low-E argon; U-0.15 / SHGC 0.20. | $2.40 | $0.00 | $2.40 | 1.00 | |
Doors | GAS | Opaque: insulated entry door, R-6. | $0.35 | $0.00 | $0.35 | 0.95 |
HPWH | Opaque: insulated entry door, R-4.75. | $0.35 | $0.00 | $0.35 | 0.95 | |
NO CI | Opaque: insulated entry door, R-4.75. | $0.35 | $0.00 | $0.35 | 0.95 | |
Air Sealing | GAS | ≤ 0.27 CFM50 per sqft of enclosure (compartmentalization); tested. | $1.20 | $0.00 | $1.20 | 0.95 |
HPWH | ≤ 0.30 CFM50 per sqft of enclosure (compartmentalization); tested. | $1.20 | $0.00 | $1.20 | 0.95 | |
NO CI | ≤ 0.27 CFM50 per sqft of enclosure (compartmentalization); tested. | $1.20 | $0.00 | $1.20 | 0.95 |
Path Comparison - Mechanical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf | OpEx |
|---|---|---|---|---|---|---|
HVAC | GAS | Hydronic-coil ducted air handler with rooftop DX condenser. Heating: AFUE 0.95, hot water supplied by the gas combi boiler (see DHW). Cooling: SEER2 16. Capacity matched per unit type. | $11.18 | $0.00 | $11.18 | 1.10 |
HPWH | Ducted cold-climate heat pump; HSPF2 9.0 to 9.5; SEER2 18.5 to 19.5; ENERGY STAR Cold Climate; ducted air handler with outdoor condenser; 1.5 ton (studio & 1BR), 2 ton (2BR). | $12.64 | $0.00 | $12.64 | 1.15 | |
NO CI | Ducted cold-climate heat pump; HSPF2 10; SEER2 20; ENERGY STAR Cold Climate; R-454B refrigerant; ducted air handler with outdoor condenser; 1.5 ton (studio & 1BR), 2 ton (2BR). | $13.27 | $0.00 | $13.27 | 1.15 | |
Ductwork | GAS | Supply and return ducts in conditioned space; R-6. | $4.42 | $0.00 | $4.42 | 1.00 |
HPWH | Supply and return ducts in conditioned space; R-6. | $4.42 | $0.00 | $4.42 | 1.00 | |
NO CI | Supply and return ducts in conditioned space; R-6. | $4.42 | $0.00 | $4.42 | 1.00 | |
Duct Sealing | GAS | The greater of 8 CFM25 per 100 sqft of conditioned floor area or 80 CFM25 to outside. | $0.76 | $0.00 | $0.76 | 1.00 |
HPWH | The greater of 8 CFM25 per 100 sqft of conditioned floor area or 80 CFM25 to outside. | $0.76 | $0.00 | $0.76 | 1.00 | |
NO CI | The greater of 8 CFM25 per 100 sqft of conditioned floor area or 80 CFM25 to outside. | $0.76 | $0.00 | $0.76 | 1.00 | |
HVAC Grading | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
Mechanical Ventilation | GAS | In-unit ERV; 40 CFM (studio & 1BR), 60 CFM (2BR); 87% SRE. | $1.90 | $0.00 | $1.90 | 1.20 |
HPWH | In-unit ERV; 40 CFM (studio & 1BR), 60 CFM (2BR); 87% SRE. | $1.90 | $0.00 | $1.90 | 1.20 | |
NO CI | In-unit ERV; 40 CFM (studio & 1BR), 60 CFM (2BR); 87% SRE. | $1.90 | $0.00 | $1.90 | 1.20 | |
Local Mechanical Exhaust | GAS | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones. Kitchen(s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH. Both: exhaust directly outdoors, ENERGY STAR certified, utilize ERV. | $1.07 | $0.00 | $1.07 | 1.05 |
HPWH | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones. Kitchen(s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH. Both: exhaust directly outdoors, ENERGY STAR certified, utilize ERV. | $1.07 | $0.00 | $1.07 | 1.05 | |
NO CI | Bathroom(s): ≥ 50 CFM intermittent & ≤ 3.0 sones OR ≥ 20 CFM continuous & ≤ 2.0 sones. Kitchen(s): ≥ 100 CFM intermittent & ≤ 3.0 sones OR continuous, ≥ 5 ACH. Both: exhaust directly outdoors, ENERGY STAR certified, utilize ERV. | $1.07 | $0.00 | $1.07 | 1.05 | |
Thermostats | GAS | Programmable smart thermostat. | $0.13 | $0.00 | $0.13 | 1.05 |
HPWH | Programmable smart thermostat. | $0.13 | $0.00 | $0.13 | 1.05 | |
NO CI | Programmable smart thermostat. | $0.13 | $0.00 | $0.13 | 1.05 |
Path Comparison - Plumbing & Appliances
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf | OpEx |
|---|---|---|---|---|---|---|
DHW | GAS | Gas tankless combi (shared with hydronic heat); UEF 0.96; 199 kBTU/h. | $6.41 | $0.00 | $6.41 | 1.25 |
HPWH | Heat pump water heater; 50 gal (studio & 1BR) / 65 gal (2BR); UEF 3.5; located in a conditioned corridor. | $2.02 | $0.00 | $2.02 | 1.20 | |
NO CI | Electric resistance storage tank; UEF 0.93; 50 gal; in-unit. | $0.95 | $0.00 | $0.95 | 0.90 | |
DHW Piping | GAS | R-3 insulation on all hot water lines; trunk-to-fixture length ≤ 35 ft (studio & 1BR), ≤ 40 ft (2BR); no recirculation. | $0.76 | $0.00 | $0.76 | 0.95 |
HPWH | R-3 insulation on all hot water lines; trunk-to-fixture length ≤ 35 ft (studio & 1BR), ≤ 40 ft (2BR), plus the corridor-to-unit run; no recirculation. | $0.76 | $0.00 | $0.76 | 0.95 | |
NO CI | R-3 insulation on all hot water lines; trunk-to-fixture length ≤ 35 ft (studio & 1BR), ≤ 40 ft (2BR); no recirculation. | $0.76 | $0.00 | $0.76 | 0.95 | |
Water Fixtures | GAS | WaterSense certified low-flow: showerhead ≤ 1.8 GPM; lavatory faucet ≤ 1.5 GPM; kitchen faucet ≤ 1.8 GPM. | $1.90 | $0.00 | $1.90 | 1.00 |
HPWH | WaterSense certified low-flow: showerhead ≤ 1.8 GPM; lavatory faucet ≤ 1.5 GPM; kitchen faucet ≤ 1.8 GPM. | $1.90 | $0.00 | $1.90 | 1.00 | |
NO CI | WaterSense certified low-flow: showerhead ≤ 1.8 GPM; lavatory faucet ≤ 1.5 GPM; kitchen faucet ≤ 1.8 GPM. | $1.90 | $0.00 | $1.90 | 1.00 | |
Refrigerator | GAS | ≤ 450 kWh/yr (studio & 1BR) / ≤ 550 kWh/yr (2BR); ENERGY STAR. | $0.82 | $0.00 | $0.82 | 1.10 |
HPWH | ≤ 450 kWh/yr (studio & 1BR) / ≤ 550 kWh/yr (2BR); ENERGY STAR. | $0.82 | $0.00 | $0.82 | 1.10 | |
NO CI | ≤ 450 kWh/yr (studio & 1BR) / ≤ 550 kWh/yr (2BR); ENERGY STAR. | $0.82 | $0.00 | $0.82 | 1.10 | |
Dishwasher | GAS | ≤ 269 kWh/yr; ENERGY STAR; standard size; electric. | $0.44 | $0.00 | $0.44 | 1.10 |
HPWH | ≤ 269 kWh/yr; ENERGY STAR; standard size; electric. | $0.44 | $0.00 | $0.44 | 1.10 | |
NO CI | ≤ 269 kWh/yr; ENERGY STAR; standard size; electric. | $0.44 | $0.00 | $0.44 | 1.10 | |
Clothes Washer | GAS | Front-load; IMEF 1.84; IWF 4.7; 141 kWh/yr; 5.0 cuft; ENERGY STAR; electric. | $0.63 | $0.00 | $0.63 | 1.10 |
HPWH | Front-load; IMEF 1.84; IWF 4.7; 141 kWh/yr; 5.0 cuft; ENERGY STAR; electric. | $0.63 | $0.00 | $0.63 | 1.10 | |
NO CI | Front-load; IMEF 1.84; IWF 4.7; 141 kWh/yr; 5.0 cuft; ENERGY STAR; electric. | $0.63 | $0.00 | $0.63 | 1.10 | |
Clothes Dryer | GAS | Electric; CEF 3.93; moisture-sensing controls; ENERGY STAR. | $0.57 | $0.00 | $0.57 | 1.00 |
HPWH | Electric; CEF 3.93; moisture-sensing controls; ENERGY STAR. | $0.57 | $0.00 | $0.57 | 1.00 | |
NO CI | Electric; CEF 3.93; moisture-sensing controls; ENERGY STAR. | $0.57 | $0.00 | $0.57 | 1.00 | |
Stove / Oven | GAS | Electric induction cooktop; convection oven. | $0.82 | $0.00 | $0.82 | 1.05 |
HPWH | Electric induction cooktop; convection oven. | $0.82 | $0.00 | $0.82 | 1.05 | |
NO CI | Electric induction cooktop; convection oven. | $0.82 | $0.00 | $0.82 | 1.05 |
Path Comparison - Electrical
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf | OpEx |
|---|---|---|---|---|---|---|
Lighting | GAS | 100% high-efficacy (LED). | $4.00 | $0.00 | $4.00 | 0.85 |
HPWH | 100% high-efficacy (LED). | $4.00 | $0.00 | $4.00 | 0.85 | |
NO CI | 100% high-efficacy (LED). | $4.00 | $0.00 | $4.00 | 0.85 | |
Solar Ready | GAS | Designated solar zone: contiguous area ≥ 40% of total horizontal roof area, free of obstructions, minimum 5 ft wide. Structural capacity for 5 PSF collateral dead load. Conduit pathways and reserved breaker space. | $0.30 | $0.00 | $0.30 | 1.00 |
HPWH | Designated solar zone: contiguous area ≥ 40% of total horizontal roof area, free of obstructions, minimum 5 ft wide. Structural capacity for 5 PSF collateral dead load. Conduit pathways and reserved breaker space. | $0.30 | $0.00 | $0.30 | 1.00 | |
NO CI | Designated solar zone: contiguous area ≥ 40% of total horizontal roof area, free of obstructions, minimum 5 ft wide. Structural capacity for 5 PSF collateral dead load. Conduit pathways and reserved breaker space. | $0.30 | $0.00 | $0.30 | 1.00 | |
EV Ready | GAS | EV-ready infrastructure for at least 20% of total parking. Branch circuit and termination for required spaces, rated at least 6.2 kVA per space. | $0.69 | $0.00 | $0.69 | 1.00 |
HPWH | EV-ready infrastructure for at least 20% of total parking. Branch circuit and termination for required spaces, rated at least 6.2 kVA per space. | $0.69 | $0.00 | $0.69 | 1.00 | |
NO CI | EV-ready infrastructure for at least 20% of total parking. Branch circuit and termination for required spaces, rated at least 6.2 kVA per space. | $0.69 | $0.00 | $0.69 | 1.00 | |
HPWH Ready | GAS | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | N/A | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | N/A | $0.00 | $0.00 | $0.00 | 1.00 |
Path Comparison - Soft Costs & Whole-Building Incentives
Item | Path | Detailed Specifications | Cost $/sf | Incentive $/sf | Net $/sf | OpEx |
|---|---|---|---|---|---|---|
Paperwork & Modeling | GAS | HERS/ERI energy model, 2021 IECC checklists, ENERGY STAR checklists, incentive documentation. | $0.14 | $0.00 | $0.14 | 1.00 |
HPWH | HERS/ERI energy model, 2021 IECC checklists, ENERGY STAR checklists, incentive documentation. | $0.14 | $0.00 | $0.14 | 1.00 | |
NO CI | HERS/ERI energy model, 2021 IECC checklists, ENERGY STAR checklists, incentive documentation. | $0.14 | $0.00 | $0.14 | 1.00 | |
Testing & Verification | GAS | Unit blower door test, total duct leakage test, mechanical ventilation testing, room balancing, pre-drywall and final inspection. | $0.00 | $0.00 | $0.00 | 1.00 |
HPWH | Unit blower door test, total duct leakage test, mechanical ventilation testing, room balancing, pre-drywall and final inspection. | $0.00 | $0.00 | $0.00 | 1.00 | |
NO CI | Unit blower door test, total duct leakage test, mechanical ventilation testing, room balancing, pre-drywall and final inspection. | $0.00 | $0.00 | $0.00 | 1.00 |
Additional Design Considerations Not Represented In This Study
- N/A