The Giordano – Smeltz Residence

"If you stop by Spartan and Hannah’s 1500 square foot home on a sunny January afternoon, you will find yourself surrounded by warmth. This isn’t because of a wood stove, or a sophisticated heating system—in fact, you will probably find that the only heat source for the house, a 12kbtu heat pump, will be off. The house will be 70 degrees through a successful combination of passive solar design and super-insulation.

Spartan and Hannah’s home doesn’t just perform under sunny conditions. True testimony to its energy efficiency can be found in data logged. Last winter the average indoor temperature was 68 degrees. At the same time, the heat pump used a mere $190 worth of electricity. Also, during the first year of operation, the 4.5 kW PV system produced a 500kW surplus; easily securing a net-positive title for the all-electric home.

Today, to construct a net zero home, builders need simply to follow “The Formula”: insulate using the R20-40-60 rule, get the ACH50 below .6, use triple pane windows, and install a 5-10 kW PV system. The question before us now is how to bring down costs, get by with a smaller PV system, and, perhaps most importantly and most frequently overlooked, decrease the energy needed to create the building.

We answered the call to improve upon The Formula not through any single measure, but through a myriad of small design solutions, most of which, like passive solar, incur little or no additional cost. Several examples follow.

A saltbox shape allows all living spaces to have south-facing glass while keeping volume low and minimizing exterior surface area. The volume of conditioned space can be further decreased by closing an air-tight door to the mudroom and adjoining pantry. An open floor plan and an air space opening between the two floors allow heat to easily rise up to the second floor. The air space between floors doubles as the location of an elegant builtin
laundry drying rack and thus there is no need for a dryer. These and many more design solutions reduce our energy load and allow us to “get away with” a relatively small PV system, just one air source heat pump, and double pane windows.

As important as it is to decrease the operational costs of a building, we would like to highlight the often overlooked embodied energy of construction. Throughout construction, we made an effort to use recycled or secondmarket product, and to decrease the use of heavy carbon footprint materials like concrete, aluminum, drywall, and foam. To this end, all of our foundation foam-board was recycled and most of our doors and windows and many other materials were purchased from second-market sources like Craigslist. Also, in order to reduce concrete, we engineered a shallow, frost protected foundation with a narrow 6” frost wall.

Spartan and Hannah’s home demonstrates ways to move beyond “The Formula.” Rather than adding another kilowatt of PV or elaborate technology, simple design choices reduce the energy footprint of our home. In order to help others learn about these ideas, our blog documents the entire building process, including performance data for the previous three years."

Quick Facts

General

Location
Saltbox
10 Charles St.
Greenfield, MA01301
United States
Building Type
Project Type
Basis of Performance Claim
Bedrooms
Conditioned Floor Area 1 500

Energy Summary

Energy Data Type
Renewable Energy System Type(s)
Ratings
Annual renewable energy generated 5 144

Envelope and Mechanicals

Subslab assembly
Foundation wall assembly

2" exterior 4" interior 6" XPS

Above grade wall assembly

double stud connected by gussets 24" O.C. mixture of platform and balloon framing, 12.5" dense pack cellulose

Door Assembly

Thermatru fiberglass XPS core, and simpson solid wood

Air Changes per hour, ACH50 0.54
Exterior house portrait Front entrance Second floor gable wall framing - west Infrared image Exterior cladding under construction Front entrance Downstairs from entrance Downstairs from southwest corner Laundry rack and Hannah Double stud framing Music studio

Project Team:

ArchitectTeam Member: Spartan Giordano

Other Team Members:

Ratings:

Awards:

Completion

Completion Date:

Scope

32'x26' Saltbox Style 2 Floor Home

Type of Construction
Number of buildings
Floor area of each building
Bedrooms
Stories 2
Conditioned Building Volume 21 054
Conditioned Floor Area 1 500

Location and Climate Details

Address
Saltbox
10 Charles St.
Greenfield, MA01301
United States
Location Type Suburaban
Climate Region Zone 5
Köppen Climate Type Dfb
Lat. / Long. POINT (-72.5994104 42.587915)
Elevation 241
Solar Insolation 166
Annual CDD and Base Temp 532 | 75
Annual HDD and Base Temp 8203 | 68

Site

Site Conditions:

previously undeveloped land,

Site Description:

Quarter acre lot in Greenfield, MA. Land needed to be cleared.

Monthly Energy Data and Utilities

Energy Data Type:

Electric Utility: WMECO

Gas Utility: None - House is 100% Electric

Renewables and Energy Balance

Renewable Energy Sources:Renewable energy is generated within the building footprint (e.g. solar PV on the roof),

Renewable Energy System Description & Details:

Annual renewable energy generated 5 144
Annual Renewable Energy Generated Data Type
Power Rating
Renewable Energy System Type(s)
Source of Annual Production Data

Walls and Roof

Double Stud connected by gussets, parallel chord trusses, vented cathedral ceiling

Subslab assembly
Subslab R-value
Slab edge assembly
Slab edge R-value 20.00
Foundation wall assembly

2" exterior 4" interior 6" XPS

Foundation wall R-value 30.00
Above grade wall assembly

double stud connected by gussets 24" O.C. mixture of platform and balloon framing, 12.5" dense pack cellulose

Above grade wall R-value 46.00
Cathedral ceiling assembly

26" Cellulose North, 21" Cellulose South

Cathedral ceiling R-value 86.00

Windows and Doors

Window Assembly:

Mix of Andersen, Marvin, Marvin integrity and Serious. All double pane except Serious, mostly double hung

Door Assembly:

Thermatru fiberglass XPS core, and simpson solid wood

Average window U-factor 0.25
Door U-Factor 0.25
Door Area 34

Mechanical Systems

Space cooling - Manufacturer & Model Mitsubishi,
Space heating - Manufacturer & Model Mitsubishi,
Domestic hot water - Manufacturer & Model 2 Panel Drainback Solar Hot Water System
Domestic hot water - capacity 80
Ventilation - Manufacturer & Model Venmar,
Lighting Manufacturer and Model
Lighting Efficiency
Mechanical Equipment Installation Details and Comments

Envelope

Air Changes per hour, ACH50 0.54
Air Changes per hour, CFM50

General Process

"Spartan and Hannah’s home demonstrates ways to move beyond 'The Formula.' Rather than adding another kilowatt of PV or elaborate technology, simple design choices reduce the energy footprint of our home. In order to help others learn about these ideas, our blog documents the entire building process, including performance data for the previous three years."

Design for Adaptability:

Software Tools

Software Tools:

General modeling information:

Lessons Learned

Outcome of Project Goals:

Discrepancies:

Rebates and Financial Incentives

Federal incentives
Local incentives
State incentives
Utility incentives
Other incentives
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