Triple Decker Design Challenge Soft Launch

Boston HiP: by ZH Architects

• This 3+ Retrofit Design renovates an existing triple decker and in the side yard adds two additional prefabricated modular townhouses (of a total of 2,400 sq. ft.), that can be customized in unit size and coun to reflect the needs of the owner.
• Estimated construction cost: $722,844 ($233,644 to retrofit the existing space and $489,200 to add additional unit(s))
• 86% decrease in annual energy use; HERS rating change: 173 to 24
• -6,892 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 15 kW
• Heating & Cooling: VRF heat pump, Hot Water: Heat pump water heater

DRAW Triple Decker: by DRAW Architecture + Urban Design

• This 3+ Retrofit Design adds an additional unit (of 723 sq. ft.) in the basement of the building. The DRAW retrofit compliments the historical frontage with a renovated multi-faceted facade system, quickly becoming state-of-the-art while staying true to its design details both in its exterior and interior.
• Estimated construction cost: $512,297 ($465,302 to retrofit the existing space and $46,995 to add an additional unit) 
• 61% decrease in annual energy use; HERS rating change: 174 to 67
• 15,000 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 17.6 kW
• Heating & Cooling: Forced air electric furnace, Hot Water: Solar hot water

Fort Hill Triple Decker: by West Faulkner and Placetailor

• This 3+ Retrofit Design adds an additional unit (of 1,313 sq. ft.) to the top of the building. This design gets a triple decker to Zero Energy and pays for itself with added leasable space and future energy savings. 
• Estimated construction cost: $699,875 ($338,800 to retrofit the existing space and $361,075 to add an additional unit) 
• 104% decrease in annual energy use; HERS rating change: 107 to -5
• 18,000 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 21.6 kW
• Heating & Cooling: Air-source heat pump (ductless & mini-splits), Hot Water: Solar assisted electric heat pump

Outside-In Inside-Out: by Leupold Brown Goldbach Architects & Scott Payette Architects

• This 3+ Retrofit Design emphasizes maximizing quality of life and increasing property values through three minimal intelligent interventions: creating additional indoor and outdoor living spaces, tightening the building envelope, and eliminating operational costs with on-site photovoltaic panels. 
• Estimated construction cost: $331,731
• 104% decrease in annual energy use; HERS rating change: 173 to -7
• 1,600 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV: 18.2 kW
• Heating & Cooling: Air-source heat pump (ductless), Hot Water: Heat pump water heater

The Back Stack: by MERGE Architects Inc. 

• This 3+ Retrofit Design adds an additional 3 story unit (of 1,100 sq. ft.) and additional outdoor spaces for existing tenants at the rear of the building. 
• Estimated construction cost: $602,010 ($288,210 to retrofit the existing space and $331,800 to add an additional unit) 
• 80% decrease in annual energy use; HERS rating change: 173 to 34
• 3,900 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 4kW
• Heating & Cooling: Air-source heat pumps (ductless), Hot Water: Heat pump water heater

Making Cents of Carbon: by DiMella Shaffer & RW Sullivan as consultant 

• This Triple Decker Retrofit Design seeks a prove that a "carbon drawdown" building is feasible and cost effective with existing technology and construction techniques by testing a replicable design and modeling approach which prioritizes a low-infiltration Passive House envelope, thermal comfort, and resiliency.
• Estimated construction cost: $326,408 (and $42,000 for Solar PV)
• 92% decrease in annual energy use; HERS rating change: 176 to 15
• 2,200 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 10 kW
• Heating & Cooling: VRF heat pump, Hot Water: Heat pump water heater

Plug-in +: by Utile Inc

• This Triple Decker Retrofit Design, Plug-in +, is a holistic retrofit design approach that prioritizes resilient systems, locally available labor and materials, and minimal resident disruption.  
• Estimated construction cost: $352,369 (and $38,606 for Solar PV)
• 84% decrease in annual energy use; HERS rating change: 173 to 27
• 14,000 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV: 9.125 kW
• Heating & Cooling: Air-source heat pump (ductless), Hot Water: Electric resistance tank

(re)Facing The Future: University of Massachusetts Amherst

• This Triple Decker Retrofit Design emphasizes continuous exterior insulation, maximum use of recycled materials, and innovative thermoelectric façade systems for all heating and cooling.
• Estimated construction cost: $329,952 (and $34,000 for Solar PV)
• 95% decrease in annual energy use; HERS rating change: 173 to 9
• 8,500 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV: 10.1 kW
• Heating & Cooling: Thermoelectric Façade system, Hot Water: Heat pump water heater

TDC Retrofit Toolkit: by Zephyr Architects

• This Triple Decker Retrofit Design provides a series of tools to help homeowners and contractors decide the most effective ways to renovate their buildings, balancing immediate costs and lifetime performance.
• Estimated construction cost: $152,149 (and $16,700 Solar PV)
• 94% decrease in annual energy use; HERS rating change: 174 to 11
• 3,500 kgCO2e embodied carbon emissions in proposed building materials. 
• Solar PV: 5.6kW
• Heating & Cooling: Air-source heat pumps (ducted), Hot Water: Hybrid heat pump water heater

The Future is Electric: Sustainable Energy Analytics

• This Triple Decker Retrofit Design focuses on improving the building envelope through reducing infiltration, proper compartmentalization, and increasing insulation and utilizing high-efficiency systems.
• Estimated construction cost: $529,564
• 79% decrease in annual energy use; HERS rating change: 297 to 34
• -261 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV size: n/a (not part of initial design, but the roof is designed to be solar ready for the future)
• Heating & Cooling: Air-source heat pump (ductless), Hot Water: Heat pump water heater

Triple Decker Deep Energy Retrofit: by Design Build Boston Construction LLC

• This Triple Decker Retrofit Design focuses on providing owners the renovation tools necessary to achieve a net-zero home with concentraction on tenant benefits.
• Estimated construction cost: $405,306 (and $57,458 for Solar PV)
• 80% decrease in annual energy use; HERS change: 173 to 34
• 18,000 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV: 18 kW
• Heating & Cooling: Air-source heat pump (ductless), Hot Water: Electric water heater

Wood Fiber Modular Encapsulation: by OPAL + TIMBER HP

• This Triple Decker Retrofit Design employs a carbon-sequestering, modular systems of building shell improvements to deliver net-zero energy performance with a negative carbon footprint. 
• Estimated construction cost: $424,509 (and $27,500 for Solar PV)
• 86% decrease in annual energy use; HERS change: 174 to 24
• -7,277 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV system: 6.5 kW
• Heating & Cooling: Air-source heat pump (ductless), Hot Water: Air-to-water heat pump

ZERO (Zero Emissions Retrofit Optimization): by Gunnison Company

• This Triple Decker Retrofit Design focuses on making a net zero renovation as compelling as possible to an owner by aligning the project incentives with their tenants and providing the most cost efficient-solution. 
• Estimated construction cost: $247,464
• 2,800 kgCO2e embodied carbon emissions in proposed building materials.
• Solar PV: 17.1 kW
• Heating, Cooling, & Hot Water: Air-to-water heat pump

• This Triple Decker Retrofit Design focuses on air-sealing a flat attic roof.
• Please note: This application is not eligible for the People's Choice award and is for educational purposes only.