Cave Residence

Inspired by issues of global warming, our goal for our new home was to create a comfortable, modern living space that produced more energy than it consumed. We also hoped to produce enough energy to power an electric car to provide the majority of our transportation. And we hoped to do this in a home that would be inviting and that could be built with “green” materials and ambitious, but proven, building techniques.

Of course, we also had aesthetic and other design goals, including aging in place, living exclusively on one floor, if necessary. As the design goals came into focus, we found that design decisions taken for other reasons kept expanding our south-facing roof. So, although great thought and care went into lowering the energy demands of the house, we also saw an opportunity to install a large, grid-tied PV array that would allow us to provide renewable energy back to the grid and reduce carbon emissions beyond what our own house would be saving.

Our goal was not to achieve net-zero by brute force, but to provide as much environmental benefit from our roof as possible. Purchasing an electric car almost as soon as we moved into our house was also a goal.

Our Wheego (the only electric car brand commercially available in our area in 2011) has been our primary source of local transportation since July of 2011. We have driven it over 8000 miles in that time (usually car-pooling to work or errands) and our PV array has provided sufficient power for the house and car with plenty to spare to share with our neighbors and to contribute significant electricity credit to charitable organizations.

Quick Facts

General

Location
18 Kennedy Drive
Hadley, MA01035
United States
Building Type Single-family residence
Project Type
Basis of Performance Claim
Bedrooms
Conditioned Floor Area

Energy Summary

Energy Data Type
Renewable Energy System Type(s)
Ratings
Annual renewable energy generated 29 944

Envelope and Mechanicals

Subslab assembly

4"Continuous Rigid Foam (Type IX EPS)

Foundation wall assembly

2.5” Continuous Rigid Foam EPS & 5.5” Formaldehyde-free Fiberglass Batts

Above grade wall assembly

11.5” Dense-pack Cellulose

Door Assembly
Air Changes per hour, ACH50 0.89

Project Team:

Other Team Members:

Ratings:

Awards:

Completion

Completion Date:

Scope

Type of Construction
Number of buildings
Floor area of each building
Bedrooms
Stories
Conditioned Building Volume
Conditioned Floor Area

Location and Climate Details

Single-family residence

Address
18 Kennedy Drive
Hadley, MA01035
United States
Location Type Suburaban
Climate Region Zone 5
Köppen Climate Type Dfa
Lat. / Long. POINT (-72.5603885 42.4115139)
Elevation 160
Solar Insolation 4.24 kWh/m2/day
Annual CDD and Base Temp |
Annual HDD and Base Temp |

Site

Site Conditions:

Site Description:

Monthly Energy Data and Utilities

Energy Data Type:

Electric Utility: Western Massachusetts Electric

Gas Utility:

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 29 944
Annual Renewable Energy Generated Data Type
Power Rating 22Watts
Renewable Energy System Type(s)
Source of Annual Production Data

Walls and Roof

Subslab assembly

4"Continuous Rigid Foam (Type IX EPS)

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

2.5” Continuous Rigid Foam EPS & 5.5” Formaldehyde-free Fiberglass Batts

Foundation wall R-value 28.00
Above grade wall assembly

11.5” Dense-pack Cellulose

Above grade wall R-value 40.00
Cathedral ceiling assembly

16" Dense-pack Cellulose

Cathedral ceiling R-value 57.00

Windows and Doors

Window Assembly:

Door Assembly:

Average window U-factor 0.19
Door U-Factor
Door Area

Mechanical Systems

Space cooling - Manufacturer & Model Mitsubishi,
Space heating - Manufacturer & Model Mitsubishi ,
Domestic hot water - Manufacturer & Model Steibel Eltron
Domestic hot water - capacity
Ventilation - Manufacturer & Model Venmar ,
Lighting Manufacturer and Model
Lighting Efficiency
Mechanical Equipment Installation Details and Comments

Envelope

Air Changes per hour, ACH50 0.89
Air Changes per hour, CFM50

General Process

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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