Pursuing EPA Indoor airPLUS Certification for Green Points or the USGBC’s LEED for Homes program? Based on our experience, there are a few key requirements to keep in mind when designing and building a project to meet EPA’s Indoor airPLUS standard. Here are the major requirements of the program, with a few of the often-overlooked requirements highlighted for easy reference.
Eligibility Prerequisite
As a prerequisite, a home must be EPA ENERGY STAR Qualified in order to participate in the Indoor airPLUS program. Populus can provide the HERS rater services as well as the Thermal Bypass Inspection to demonstrate your project’s compliance with the requirements of ENERGY STAR for New Homes.
Materials
There are a few materials specifications that are especially important to keep in mind. First, all pressed wood materials (i.e. plywood, OSB, MDF and cabinetry) must be certified low-formaldehyde. Next, interior paints and finishes must be low-VOC or no-VOC. Finally, all carpet, carpet adhesives and cushions must qualify for CRI Green Label Plus or Green Label testing program.
Moisture Control Measures
When preparing site plans and construction drawings, remember to specify the following moisture control measures:
Site & Foundation:
- Site & foundation drainage: sloped grade, protected drain tile & foundation floor drains
- Capillary break below concrete slabs & in crawlspaces (with specific exceptions for free draining soils and dry climates)
- Foundation wall damp-proofed or water-proofed (except where no below-grade walls)
Wall Assemblies:
- Continuous drainage plane behind exterior cladding, properly flashed to foundation
- Window & door openings fully flashed
Roof Assemblies:
- Gutters/downspouts direct water a minimum of 5′ from foundation (exception for dry climates)
- Fully flashed roof/wall intersections & roof penetrations
- Bituminous membrane installed at valleys & penetrations (exception for dry climates)
- Ice flashing at eaves (except Climate Zones 1 – 4)
Interior:
- Moisture-resistant materials/protective systems installed (i.e. flooring, tub/shower backing)
- No vapor barriers installed on interior side of exterior walls with high condensation potential
- No wet or water-damaged materials enclosed in building assemblies
Radon Measures
Indoor airPLUS requires that homes built in EPA Radon Zone 1 be constructed with approved radon-resistant features according to EPA Building Radon Out; NFPA 5000, Chapter 49; IRC, Appendix F; CABO, Appendix F; or ASTM E1465. Indoor airPLUS recommends, but does not require, that radon-resistant features be used for homes built in EPA Radon Zones 2 and 3. In addition, the builder must provide two radon test kits with instructions for homebuyers in Radon Zones 1 and 2.
Pests
- Foundation joints & penetrations sealed, including air-tight sump covers
- Corrosion-proof rodent/bird screens installed at openings that cannot be fully sealed
HVAC
To achieve Indoor airPLUS certification, projects must have HVAC room loads calculated and documented and system design documented. In addition, projects must have duct system design documented (i.e. a Manual D) and ducts properly installed (there is an exception for projects that have room-by-room duct system testing performed, however projects in the City and County of Boulder will need an ACCA Manual D for code compliance). Populus now offers ACCA Manual J load calculating services and ACCA Manual D services that will allow your project to meet these requirements.
In addition, Indoor airPLUS requires the following HVAC specifications:
- No air handling equipment or ductwork installed in garage (ducts in floor cavities over garages but outside of the fire-rated envelope are allowed); continuous air barrier for adjacent assemblies
- Rooms pressure balanced as required (via dedicated returns, transfer grilles, jump ducts or door undercut) OR tested
- Whole house ventilation system (e.g., a continuously operating exhaust fan or an HRV) installed to meet ASHRAE 62.2 requirements (it is good practice to have your mechanical contractor test the flow rates for installed venitlation systems and to minimize the number of elbows in the system which may result in a lower air flows than the equipment’s rated performance capacity)
- Local exhaust ventilation to outdoors installed for baths, kitchens, clothes dryers, central vacuum system, etc.
- Central forced air HVAC systems must have minimum of MERV 8 filter, no filter bypass & no intentional ozone generation (electronic air cleaners cannot be MERV rated and therefore, do not meet the requirement; further the performance of these cleaners tends to decrease as the systems becomes dirty, unlike standard filters which filter finer particles as they become dirty)
- In warm-humid climates, additional dehumidification measures are required
Combustion Pollutants
Combustion Source Controls
- Gas heating equipment must be direct vented; oil heat & water heaters must be power vented or direct vented (with a few exceptions)
- Fireplaces/heating stoves vented outdoors & meet emissions/efficiency standards/restrictions
- Certified CO alarms installed in each sleeping zone according to NFPA 720
- Certain smoking prohibitions for multi-family projects
Attached Garage Isolation
- Common walls/ceilings air-sealed before insulation installed; house doors gasketed & closer installed
- Exhaust fan (min. 70 cfm rated for continuous use) installed in garage & vented to outdoors
Before Occupancy
Before occupancy, the HVAC system & ductwork must be verified dry, clean and properly installed. Populus recommends covering all duct registers to prevent dust from entering ductwork during construction. In addition, the home should be ventilated before occupancy or initial ventilation instructions must be provided to the buyer. Additional requirements for pre-occupancy home commissioning include:
- HVAC contractor must document measured airflow or pressure drop across the cooling coil or heat exchanger within +/- 15% of system design airflow or manufacturer-specified operating range
- HVAC contractor must document the installation and testing of proper refrigerant charge
Visit EPA’s Indoor airPLUS program to see a full set of program requirements and to learn more. You can contact Populus at info@popboulder.com to find out how your project can participate in the program.
Populus is a Boulder-based, full-service sustainable design consulting firm that focuses on high performance, net-zero and near-net-zero custom residential and multi-family projects. Populus is your partner in high-performance design solutions, specializing in energy efficiency codes, green building certifications and LEED for Homes™ training. Contact Populus at news@popboulder.com.
