Healthy Home Office and Warehouse

As a homebuilder and home performance contractor, energy efficiency is integral to everything we do. When we needed a new headquarters for Healthy Home Energy & Consulting, we decided to build a net-zero facility that would use no fossil fuels and produce as much or more energy on site than we would use on an annual basis. After searching for a location that would offer relatively flat property and a due-south orientation, we selected a 90-year old pole-barn-style highway department garage—a commercial building in a residential neighborhood that could be easily retrofitted. The large south facing roof area was strategic to the efficiency of our 10 solarthermal and 56 solar-photovoltaic roof panels. We developed a design for a light-duty commercial space that would meet our needs. We used OptiMiser modeling software to conduct energy calculations before choosing our mechanical systems.

Within the salvaged footings and framing, we installed Zip System Rsheathing to reduce the number of products needed between the studs and siding. Recycled lumber from work sites was used for interior trim. We used Hardie-Plank exterior siding made of sustainable materials.

Inside, we started with a very tight envelope with as much R-value as we could fit into the cavities. We used low-VOC spray foam to insulate our thermal envelope including the underside of the roof. Our building is extremely air tight with an ACH50 number of 1.16. To compensate for that tightness we installed a Zehnder 550 ERV. This system controls the air flow in the building to ensure that the appropriate amount of fresh air for comfort and indoor air quality is present at all times.

On winter workdays, we heat our office by fueling our 93-percent efficient,Twinfire wood-burning stove with salvaged logs from our work sites. This heat is supplemented by radiant heat in the slab for the office and storage areas generated by our solar thermal panels. Our irrigation needs are fulfilled by a rainwater harvesting system that collects water from the roof of the building.

In order to maximize energy efficiency, we chose Energy Star-rated windows, doors, appliances and electronics. In some ways, the building is more similar to a home than a commercial building because we have all the amenities of a typical home.

Building the most energy-efficient home or workplace isn’t a productive exercise if there are no goals or systems in place for measuring performance. Therefore, sensors throughout the building report continuous data such as real time energy production and usage, indoor and outdoor temperature and humidity, VOC and CO levels, Solar Thermal BTU production and usage, ERV status and flow, and rainwater tank levels. Our monitoring system is cloud based so that we can “check-in” from anywhere and at any time.

Our new headquarters benefits both our employees and our community, as we removed an eyesore from a residential neighborhood and created an attractive, responsibly-constructed commercial building in its place.

This is a replicable net-zero energy model for both light-duty commercial and residential use.

 

 

 

 

Quick Facts

General

Location
200 Tomahawk Street
Yorktown Heights, NY10598
United States
Building Type Office & Warehouse
Project Type
Basis of Performance Claim
Bedrooms
Conditioned Floor Area 2 400

Energy Summary

Energy Data Type
Renewable Energy System Type(s)
Ratings
Annual renewable energy generated 19 953

Envelope and Mechanicals

Subslab assembly

3 continuous inches of 2 pound closed cell foam (Manufacturer: Heatlok Soy by Demilec)

Foundation wall assembly
Above grade wall assembly

1 continuous inch of Polyiso rigid foam (Zip wall R-Sheathing system by Huber, R-Value: 6.6), 1.5” of 2 pound closed cell foam, (Manufacturer: Heatlok Soy by Demilec, R-Value: 10.5)
2” of 3/4 pound open cell foam (Manufacturer: Agribalance by Demilec, R-Value: 9)

Door Assembly
Air Changes per hour, ACH50

Project Team:

BuilderTeam Member: Kevin Brenner

Other Team Members:

Ratings:

Awards:

Completion

Completion Date:

Scope

Type of Construction
Number of buildings
Floor area of each building
Bedrooms
Stories 1
Conditioned Building Volume
Conditioned Floor Area 2 400

Location and Climate Details

Office & Warehouse

Address
200 Tomahawk Street
Yorktown Heights, NY10598
United States
Location Type Suburaban
Climate Region Zone 6
Köppen Climate Type Dfa
Lat. / Long. POINT (-73.7502064 41.329641)
Elevation 590
Solar Insolation 4.33 kWh/m2/day
Annual CDD and Base Temp 696 | 75
Annual HDD and Base Temp 6604 | 68

Site

Site Conditions:

previously developed land, running water, preexisting structure(s),

Site Description:

I spent a year searching for the right location that would offer relatively flat property and a due-south orientation to support the net-zero goals. Proximity to the Brenner Builders office in Bedford Hills was paramount. After eliminating dozens of options due to excessive shade, incorrect exposure, or roof pitch (which would have hampered the efficiency of the solar systems), I received a call from my broker about a new listing in the town of Somers – only a 16 minute drive from Bedford Hills.

The structure at 200 Tomahawk Street was built in the 1920s as a polebarn- style garage for the Somers Highway Department. It was a commercial building in a residential neighborhood, so its non-conforming-lot status came with limitations. While the footprint could not be changed, it had all the other elements required for a successful net-zero endeavor, with the added advantage of being on a well-traveled street. From a marketing point of view, the site was perfect for exposure and recognition.

Monthly Energy Data and Utilities

Energy Data Type:

Electric Utility: NYSEG

Gas Utility:

Renewables and Energy Balance

Renewable Energy Sources:

Renewable Energy System Description & Details:

Annual renewable energy generated 19 953
Annual Renewable Energy Generated Data Type
Power Rating
Renewable Energy System Type(s)
Source of Annual Production Data

Walls and Roof

Subslab assembly

3 continuous inches of 2 pound closed cell foam (Manufacturer: Heatlok Soy by Demilec)

Subslab R-value 21.00
Slab edge assembly

1” continuous inch of XPS designed more as a thermal break than as insulation (Manufacturer: Dow Chemical Company)

Slab edge R-value 5.50
Foundation wall assembly
Foundation wall R-value
Above grade wall assembly

1 continuous inch of Polyiso rigid foam (Zip wall R-Sheathing system by Huber, R-Value: 6.6), 1.5” of 2 pound closed cell foam, (Manufacturer: Heatlok Soy by Demilec, R-Value: 10.5)
2” of 3/4 pound open cell foam (Manufacturer: Agribalance by Demilec, R-Value: 9)

Above grade wall R-value 26.10
Cathedral ceiling assembly

3” of 2 pound closed cell foam in the roof cavities (Manufacturer: Heatlok Soy by Demilec), 10” of 3/4 pound open cell foam in the roof cavities over the closed cell foam and
over the roof rafters to inhibit thermal bridging. (Manufacturer: Agribalance by Demilec)

Cathedral ceiling R-value 66.00

Windows and Doors

Window Assembly:

Door Assembly:

Average window U-factor 0.29
Door U-Factor
Door Area

Mechanical Systems

Space cooling - Manufacturer & Model Water Furnace,
Space heating - Manufacturer & Model Various,
Domestic hot water - Manufacturer & Model American Water Heater Co.
Domestic hot water - capacity
Ventilation - Manufacturer & Model Zehnder,
Lighting Manufacturer and Model
Lighting Efficiency
Mechanical Equipment Installation Details and Comments

Envelope

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

General Process

During the design phase, I worked with Brian Stumpf, an architect, and long-time Brenner Builders project manager, on the construction plans for the building and systems. We applied Brenner Builders’ and Healthy Home’s experience, expertise, and building-science principles
throughout the process

Design for Adaptability:

Software Tools

Software Tools:

OptiMiser

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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