Completion date


Two primary occupants spend 342 days per year at residence.

Days per year Building is fully occupied:


Project was a zero net energy DER complete renovation effecting all rooms. Insulation was added per National Grid DER requirements. Oil steam heating system was replaced with air source heat mini-split heatpumps to heat and cool the house. The original chimney was removed. The gas water heater was replaced by a heat pump water heater and the gas stove was replaced with an electric induction stove. A drain heat recovery system was added to recover shower drain heat. Kitchen was relocated over garage, dining room was enlarged, and both bathrooms were renovated. Garage door walls and garage door were also insulated. High solar gain low heat loss triple pane Argon filled windows replaced original windows. 7.35 kW PV array added to solar power the house to achieve net zero energy.

Type of Construction Retrofit
Bedrooms 3
Bathrooms 2.0
Stories 2
Conditioned Building Volume 18,210 cu ft
Conditioned Floor Area 2,706 sq ft

Location and Climate Details

Single-family residence

85 Laurel St
Melrose, MA 02176
United States
Location Type Suburaban
Climate Region Zone 5
Köppen Climate Type Cfa
Lat. / Long. POINT (-71.054738 42.454879)
Elevation 120 ft
Solar Insolation 4.47 kWh/m2/day
Annual CDD and Base Temp 927 | 75 deg F
Annual HDD and Base Temp 6484 | 68 deg F


Site conditions:
previously developed land, preexisting structure(s)
Site description:

Site is 60 ft wide x 100 ft long with a measured annual solar access average of 87% using Solmetric SunEye. One ash tree on the back southern boundary blocks some sunlight and a very large oak tree on a neighbor's property to the east blocks some additional early morning light from the PV in the summer.

Materials and Design Strategy


Two layers of recycled 3 inch polyiso obtained from other buildings was used on the DER roof to save funds and recycle materials. Bricks from chimney were saved and will be used as a garden edging or material for a patio. Rather than replacement, the original garage carriage doors were repaired and insulated with donated Spaceloft and 2 inch thick pink XPS.

Special architectural measures:

The R-8 high solar gain Schuco triple pane windows used are passive house certified.

Indoor Environment Description:
Heat, cool, & dehumidify with two air source mini-split heat pumps Ventilate whole house and filter air with HRV in attic Dehumidify basement in summer with heat pump water heater