Green Zero Carbon Home

We cut the carbon dioxide emissions of our 5300sf 1970's house by 43 tons per year getting us to a year round zero-carbon footprint. We are not only  saving money, our bills (for heating oil and electricity) are down $11,500 a year, but we are earning a 15% return on our investment. That's 15% after tax and with no volatility. Much better than my stock and bond investments! For more information, check out www.greenzerocarbonhome.com.

Quick Facts

General

Location
119 Farm St
Dover, MA02030
United States
Building Type single-family residence
Project Type Zero Energy
Basis of Performance Claim
Bedrooms 5
Conditioned Floor Area 5 300

Energy Summary

Energy Data Type Measured,
Renewable Energy System Type(s) Photovoltaics,
Ratings

Claims are based on my own detailed tracking of electricity use, solar electricity generation and heating oil use. I have daily spreadsheets for over a year detailing this but heating oil use was measured by me reading the gauges of our oil tanks and there is no utility documentation.

Annual renewable energy generated 15 000

Envelope and Mechanicals

Subslab assembly

concrete

Foundation wall assembly
Above grade wall assembly

2x4 walls with fiberglass insulation, approx R12

Door Assembly
Air Changes per hour, ACH50
Our solar panel array on the roof of our house our "Green Zero Carbon Home" Our heat pumps which cut our carbon footprint by 20 tons a year

Project Team:

Team Member: David Green

Other Team Members:

Ratings:

Claims are based on my own detailed tracking of electricity use, solar electricity generation and heating oil use. I have daily spreadsheets for over a year detailing this but heating oil use was measured by me reading the gauges of our oil tanks and there is no utility documentation.

Awards:

None

Note that HERS index and Energy Star score are only available on new construction this is a renovation. There are no awards that I am aware of that apply to renovations. Perhaps you should start one? Since 99% of the US housing stock is already existing successful retrofits are important to publicize. Especially those that make money. None of your case studies shows the investment or return. In fact your case studies make no mention of money and therefore a reader cannot tell if this makes financial sense for them.

Completion

Completion Date: Thursday, March 1, 2018

Scope

Renovation. Added triple glazed windows. Added R10 insulation to roof and R38 to basement.

Type of Construction Renovated, Part of Building,
Number of buildings
Floor area of each building 5 300
Bedrooms 5
Stories 2
Conditioned Building Volume
Conditioned Floor Area 5 300

Location and Climate Details

single-family residence

Address
119 Farm St
Dover, MA02030
United States
Location Type Rural
Climate Region Zone 6
Köppen Climate Type Dfb
Lat. / Long. POINT (-71.328383 42.225533)
Elevation 250
Solar Insolation
Annual CDD and Base Temp |
Annual HDD and Base Temp 5800 | 65

Site

Site Conditions:

preexisting structure(s),

Site Description:

Gentle slope, mostly wooded

Monthly Energy Data and Utilities

Energy Data Type:

Electric Utility: Eversource

Gas Utility: none

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 15 000
Annual Renewable Energy Generated Data Type Measured,
Power Rating 15 670Watts
Renewable Energy System Type(s) Photovoltaics,
Source of Annual Production Data Metered

Walls and Roof

renovation of existing 10"x2" joists on flat roof

Subslab assembly

concrete

Subslab R-value 1.00
Slab edge assembly
Slab edge R-value
Foundation wall assembly
Foundation wall R-value 1.00
Above grade wall assembly

2x4 walls with fiberglass insulation, approx R12

Above grade wall R-value 12.00
Cathedral ceiling assembly
Cathedral ceiling R-value

Windows and Doors

Window Assembly:

Loewen triple glazed patio doors. R4 on lower floor R 5 on upper floor.

Door Assembly:

Average window U-factor 0.22
Door U-Factor
Door Area

Mechanical Systems

Space cooling - Manufacturer & Model same,
Space heating - Manufacturer & Model Bosch 5 ton heat pumps (2),
Domestic hot water - Manufacturer & Model State heat pump hot water tank
Domestic hot water - capacity 80
Ventilation - Manufacturer & Model
Lighting Manufacturer and Model LED light bulbs,
Lighting Efficiency
Mechanical Equipment Installation Details and Comments

Envelope

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

General Process

We did it ourselves after a lot of research

Design for Adaptability:

Software Tools

Software Tools:

General modeling information:

My own spreadsheets. I created model of our house that has a R-squared of 80% to the actual energy use of the house.

Lessons Learned

Outcome of Project Goals:

We got to a zero carbon footprint, zero utility bills and are making a 15% return on investment

Discrepancies:

Rebates and Financial Incentives

Federal incentives

30% federal tax credit on solar panels, about $23,000

Local incentives
State incentives

MA SREC2 solar power subsidy, about $29,000

Utility incentives

$1500 utility rebate on heat pumps

Other incentives
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