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Balanced HRV/ERV


Installed correctly, a whole-house fresh air system with heat recovery can help ensure a healthier and more comfortable indoor environment with optimum efficiency.

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This U.S. Department of Energy checklist includes important specifications that can contribute to a complete and quality installation. All work shall comply with these specifications, all relevant codes and standards, and all manufacturer installation instructions. The contractor shall check each box on the checklist below and sign and date at the bottom to certify the work is completed.


For continuous operation, the target ventilation rate for the home shall be based on house size as follows: 50 cfm for up to 1,500 ft², 70 cfm for 1,501 to 2,500 ft², and 100 cfm over 2,500 ft². For intermittent operation, the average air flow shall meet the minimum target ventilation rate specified above (e.g., if the controller operates the air handler fan for a minimum of 20 minutes each hour, then three times the target ventilation air flow is needed).

Appropriate ventilation equipment shall be selected based on the target ventilation rate and the climate.

The ERV/HRV shall either be connected to the central air handler and use the HVAC ducts for supply air, or have its own independent supply ducts. Return air intakes can either be individually ducted from several rooms or ducted from one or more central locations,
or the ERV/HRV can use the HVAC system returns. It is recommended that each occupied room with a door have at least one ducted supply, or one ducted return, or both.

An HRV/ERV that is connected to the central system supply side shall have a damper to keep air from flowing backward through the unit when the ventilator is off. Each occupied room should have one ducted supply or return or both.

Outdoor air shall be filtered with a MERV 11 filter or higher, and the pressure drop across the filter shall match equipment capabilities. The filter shall be installed to be easily accessible by occupants.

The fan shall be oriented so the equivalent length of the duct run is as short as possible. "Equivalent length" shall be calculated in accordance with ANSI/ACCA Manual D Residential Duct Systems.

The exhaust duct outlet vent shall be located on the exterior of the home where it does not direct air flow onto a walkway and it is situated at least 10 feet from any air inlet.

Outdoor air intakes shall be equipped with screens to keep out insects and debris, integrated with siding including flashing required to prevent water intrusion, and sealed with caulk or spray foam where the edges of the duct meet the exterior walls or ceilings to limit the infiltration of exterior air into the home.

All duct seams and connections shall be sealed with mastic or UL 181 tape.

Ducts installed outside of the thermal envelope shall be insulated to a minimum of R-8.

The ventilation rate shall be measured using a flow hood, flow grid, or anemometer, in accordance with test procedures listed in ANSI/RESNET/ICC 380-2016, to ensure that the fan is providing the minimum ventilation rate specified above.

All operation and maintenance procedures shall be reviewed with the homeowner (e.g., how and when to change filter).

All operation and maintenance procedures shall be reviewed with the homeowner (e.g., how and when to clean the intake screen).

Balanced HRV/ERV Background

Balanced HRV/ERV

Contaminants in homes can trigger asthma and allergy attacks as well as other health problems. Whole-house fresh air systems dilute these contaminants. Balanced ventilation systems like heat recovery ventilators (HRVs) and energy recovery ventilators (ERVs) bring in fresh outside air and distribute it throughout the home using either their own dedicated ducts or the home’s central heating and cooling system ducts. While bringing in this fresh air, the ERV/HRV exhausts an equal amount of stale air from the home, ensuring balanced pressures throughout the home. The incoming and outgoing air pass through a heat exchanger where heat is transferred from the warmer air stream to the cooler air stream, thus heating incoming air in the winter and cooling incoming air in the summer. An ERV also transfers moisture.

Tips to Sell Quality Installed Home Improvements

Home Improvement Expert is a valuable tool for organizations committed to quality installed work. The following tips help optimize the value of this tool when selling home improvements:

Trust Matters: Inform homeowners how your work conforms to this world-class expert guidance. Recommend they visit the DOE website as evidence these are indeed official best practices.

Knowledge Matters: Take advantage of the Building America Solution Center as a resource for becoming an expert on these projects.

Clarity Matters: Tell prospective clients to contrast your expert-recommended best practices with other contractors.

Value Matters: Advise prospective clients to insist other bids also include these checklists to ensure equivalent quality work.

Message Matters: Showcase on your website and marketing materials that your company uses the highest quality best practices specified on HIE Checklists.

Experiences Matter: Provide visual evidence contrasting the difference between poor and high quality work such as infrared images; pre- and post-energy bills; short and long warranties; and simple charts and graphics depicting performance advantages.

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