6.6202.2 Heat Recovery Ventilator (HRV) and Energy Recovery Ventilator (ERV) Installation

Topic: 
Whole Building Ventilation
Subtopic: 
Components
Desired Outcome: 
HRV HRV Heat recovery ventilator and ERV ERV Energy recovery ventilator systems installed to specifications
Note: 
The authority having jurisdiction may require that a licensed professional perform certain tasks outlined in this detail.
TitleSpecification(s)Objective(s)
6.6202.2a
Wiring

Wiring will be installed in accordance with original equipment manufacturer specifications, and local and national electrical and mechanical codes

Prevent an electrical hazard

6.6202.2b
Access

Fans, service switch Service switch An electrical switch that controls the complete flow of electricity to a mechanical device , filters, drain, and drain pan will be accessible for maintenance in accordance with authority having jurisdiction

Maintain designed air flows and system performance

Ensure occupant health and safety

6.6202.2c
Fan mounting

Fan will be securely mounted in accordance with manufacturer specifications

Fan will be oriented so the equivalent length of the duct run is as short as possible; calculate "equivalent length" in accordance with ANSI ANSI American National Standards Institute, www.ansi.org / ACCA ACCA Air Conditioning Contractors of America, www.acca.org Manual D (Residential Duct Systems)

Fan will be isolated from the building framing unless specifically designed to be directly attached

Ensure short duct runs achieve optimum air flows

Ensure fan is mounted securely

Ensure fan housing or building framing does not shake, rattle, or hum when operating

Minimize noise

6.6202.2d
Backdraft dampers (required for intermittent operation)

A backdraft damper Backdraft damper A damper that allows air to flow in only one direction will be installed between the heat recovery ventilator ( HRV HRV Heat recovery ventilator ) or energy recovery ventilator ( ERV ERV Energy recovery ventilator ) and the exterior, unless the system operates continuously

Outdoor air intakes and exhausts will be equipped with automatic or gravity dampers that close when the ventilation system is not operating

Prevent reverse air flow when the system is off

6.6202.2e
Installation of fittings

Collar will be at least the same diameter as the exhaust fan outlet; if collar is larger than exhaust fan outlet, a rigid metal transition will be used

Fitting will be appropriate for regional weather conditions and installation location on house so as not to be rendered inoperable

Achieve the desired air flows to and from the designated locations

Ensure unrestricted air flow

Preserve integrity of the building envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier

6.6202.2f
Duct connections

Ducts will be connected to applicable registers or grilles, collector box, HRV HRV Heat recovery ventilator or ERV ERV Energy recovery ventilator , intake fitting, and termination fitting

Ducts will be connected and sealed as follows:

  • Metal-to-metal or metal-to-PVC will be fastened with a minimum of three equally spaced screws
  • Flexible duct-to-metal or flexible duct-to-PVC will be fastened with tie bands using a tie band Tie band A strap, often made of nylon, that mechanically squeezes a flexible duct to a fitting. Must have a minimum performance temperature rating of 165° (per UL 181A-type test) and a minimum tensile strength rating of 50 pounds tensioning tool
  • Flexible duct between tie band Tie band A strap, often made of nylon, that mechanically squeezes a flexible duct to a fitting. Must have a minimum performance temperature rating of 165° (per UL 181A-type test) and a minimum tensile strength rating of 50 pounds and end of metal or PVC duct will be screwed into place
  • PVC-to-PVC materials will be fastened with approved PVC cement
  • Other specialized duct fittings will be fastened in accordance with manufacturer specifications
  • In addition to mechanical fasteners, duct connections will be sealed with UL UL Underwriters Laboratories 181B or 181B-M listed material

Achieve the desired air flows to and from the desired locations

Preserve integrity of the duct system and building envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier

6.6202.2g
Duct layout

Air to be exhausted to the outdoors will not be taken directly from the forced air system

Supply ducts attached to the return side of forced air systems will be:

  • Attached as close to the HVAC HVAC Heating, ventilation, and air conditioning system's fan as possible while remaining in compliance with manufacturer specifications
  • Set up to provide filtration of outdoor ventilation air before reaching the HVAC HVAC Heating, ventilation, and air conditioning system with minimum MERV MERV Minimum efficiency reporting value 6 filter
  • Connected to the intake fitting
  • Connected and sealed in accordance with the supply duct detail

Achieve the desired air flows to and from the desired locations

Preserve integrity of duct system and house

Ensure occupant health and safety

6.6202.2h
Insulation

Ducts installed outside of the thermal envelope Envelope The separation between the interior and exterior environments of a building that includes a combination of air and thermal barrier will be insulated to a minimum of R-8 or equivalent to local codes

Preserve integrity of the duct system by eliminating condensation

6.6202.2i
Sealant selection

Gap between registers or grilles and interior surface will be sealed

Sealants will be compatible with their intended surfaces

Sealants will be continuous and meet fire barrier specifications

Prevent air leakage around registers or grilles

Ensure a permanent seal

Prevent a fire hazard

6.6202.2j
Balance and flow

Air flows will be measured and adjusted to match to the system's intent

Achieve the desired air flows to and from the desired locations

6.6202.2k
Occupant education

Occupant will be educated on how and when to change filter and clean drain pan, if applicable, according to manufacturer specifications

Ensure occupant health and safety

Preserve integrity of system