Name
Erika DeRoche
08/28/2023 20:52
Building company
Alpha Smart Builders
Builder's name
Deliandro Dias
Architecture firm
ZeroEnergy Design
Architect's name
Erika DeRoche
Passive building consultant
ZeroEnergy Design
Date when the project began or is expected to begin (enter "01" for the day if you only know the month and year)
01/04/2022
Type of structure
wood-frame
Town or city
Cambridge
State or province
MA
Original construction year
1902
Year when passive building work was or will be completed
2023
Lot type
urban
Building use type
residential
Brief description of the retrofit project
Emergency reconstruction/ gut renovation of three-unit affordable triple decker with energy efficiency focus following a fire. Most of the existing siding remained with insulation and air sealing occurring from the interior, in addition to window replacement with triple glazed tilt/turn uPVC windows, electrification, all new building systems and complete interior renovation. The project is not attempting passive house certification but achieved DOE's Zero Energy Ready Homes certification and anticipates Enterprise Green Communities certification.
Type of retrofit
Why did you choose to do a whole, partial, or phased retrofit?
What were the main goals of the retrofit?
Was this a registered historic building?
no
Did you use historic tax credits?
no
Total area of the structure (in square feet)
4700
Passive house certified?
no
If certified by another group, please list the organization:
How many months did the renovation take? If ongoing, how many months is the renovation expected to take?
12
Were people living in the building during renovation?
no
Air tightness (ACH)
Energy use intensity (EUI)
Annual electricity usage (kWh)
Annual electricity costs (USD)
Annual heat usage (kBtu)
Annual heat costs (USD)
Heat source(s)
other
Annual hot water usage (kWh)
Annual hot water cost (USD)
Hot water system
other
Air tightness (ACH)
1.46
Energy use intensity (EUI)
16.06
Annual electricity usage (kWh)
22155
Annual electricity costs (USD)
4431
Annual heat usage (kBtu)
Annual heat costs (USD)
1740
Heat source(s)
heat-pump
Annual hot water usage (kWh)
2658
Annual hot water cost (USD)
532
Hot water system
air-source-heat-pump
Is the retrofit now using renewable energy sources?
no
If using renewable energy, please describe the type, kWh generation and any other system specs
Were/are any passive house certified materials used?
Please describe your reasoning in using certified or non-certified materials
Door type before renovation
hollow masonite
Door type after renovation
insulated fiberglass
Please describe any methods you're using for controlling thermal bridging, water, vapor and air movement related to doors
U-value of doors before renovation
U-value of doors after renovation
0.14
Window type before renovation
Dual-glazed, Double Hung Vinyl replacement window
Window type after renovation
Triple-glazed, argon-filled uPVC casement window
Please describe any methods you're using for controlling thermal bridging, water, vapor and air movement related to windows
U-value of windows before renovation
U-value of windows after renovation
0.16
Materials in the wall assembly before renovation (listed from outside to inside)
12” brick and field stone foundation wall
Materials in the wall assembly after renovation (listed from outside to inside)
12” brick and field stone foundation wall with limited repointing, 3” low-GWP closed cell spray foam insulation, stud wall finished with type X gypsum wallboard
Please describe methods for controlling thermal bridging, water, vapor and air movement related to the wall assembly, e.g. materials used and construction
Space between stud wall and foundation wall for continuous spray insulation, dimpled membrane/mat
R-value of wall assemblies before renovation
R-value of wall assemblies after renovation
18
What rough percentage (0 - 100) of the wall assemblies have thermal bridges after renovation?
5
Materials in the roof assemblies before renovation
Rigid insulation of sheathing, EPDM roofing membrane, existing board sheathing, 7” existing rafters
Materials in the roof assembly after renovation
Adhered TPO roofing system, ½” protection board, R-33 polyiso rigid insulation, vapor retarder, existing or new sheathing, 7” existing rafters dense packed with cellulose, vapor variable air barrier
Please describe methods for controlling thermal bridging, water, vapor and air movement related to the roof assembly, e.g., materials and construction
R-value of roof assemblies before renovation
R-value of roof assemblies after renovation
59
Please upload up to four images of the structure and/or retrofit
Ventilation strategy (type and number of ERV or HRV) before renovation
Natural ventilation
Ventilation strategy (type and number of ERV or HRV) after renovation
Individual Broan ERV for each apartment, Kitchen hood direct vent to exterior.
If any make-up air systems were used, please describe
Make-up air ventilator for basement laundry room.
Please describe any thermal bridging issues before renovation
Uninsulated walls and foundation wall, extensive existing wood structure and blocking.
Please describe strategies to mitigate thermal bridging after the renovation
Utility/electrical chase at interior allowed for interior insulation between furring, flash & batt used at overhanging second floor and basement ceiling beneath front entry.
Please describe any moisture issues before renovation
Please describe the moisture control strategy after renovation
Drainage mat installed at interior of foundation wall, dehumidifier installed in basement, epoxy coating applied to existing slab, reconstructed roof corner, positive roof drainage to interior drain/overflow drain, new roof edge, limited repointing of brick foundation wall, careful detail and execution of opening and penetration flashing.
On a scale of 1 to 10, what was the perceived comfort of the structure before renovation?
On a scale of 1 to 10, what is the perceived comfort of the structure after renovation?
What was the total cost, or estimated cost, of design for the retrofit project (in dollars)?
1414306
Total construction cost per square foot, or estimated cost, for the project (in dollars)
300
Roughly what percentage (0 - 100) of the project was financed?
What types of funding did you use?
other
Total door cost (in dollars)
Total windows cost (in dollars)
84326
Total wall assembly cost (in dollars)
Total roofing cost (in dollars)
Total ventilation cost (in dollars)
83750
Total foundation cost (in dollars)
What is the expected life of this retrofit (in years)?
100
If you calculated it, what was the energy return on investment, i.e. the EROI (in dollars)?
On a scale of 1 to 10, how much did you take the EROI into consideration before starting the project (if it was calculated)?
Please upload up to four images of the structure and/or retrofit
What would you say was the most successful part of the process?
Electrification greatly improves the operational carbon for this property. We also achieved excellent whole building air tightness for a retrofit.
Rate the following in terms of difficulty...
Section 1: Contact
The first section is just to get your contact info...
Working with your builder and/or architect
Procuring materials
Technical challenges
Local regulations and rules
Financing
What do you wish you knew before starting the project?
I wish we had required compartmentalization mock-ups and coordinated the data and cable riser before construction.
If you do another retrofit, what would you do differently?
Ideally we would air seal and insulate from the exterior and pair that work with siding replacement, maintaining interior dimensions to the greatest extent possible. In this instance the siding was requested to remain.
Any additional notes or comments
After the renovation, the Annual Heat Usage is anticipated to be 6,179.4 kWh (units different than indicated in question above).
The project was funded with an insurance claim and a number of different grants, including energy-related grants from MassCEC. Window replacement was partially funded with a historic preservation grant (after Historic Commission approval).