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 |