Do I need an HRV or an ERV?
HRV (Heat Recovery Ventilator)
If you use a heating system more often than air conditioning, you need an HRV.
Heat recovery systems have been designed to recover the heat contained in exhaust air.
ERV (Energy Recovery Ventilator)
If you use the air conditioning more than a heating system, an ERV is recommended.
Energy recovery systems have been designed to recover the energy contained in exhaust air.
Types of installation
Exhaust and supply in return – Good
When using this application make sure that there is minimum 6 feet between the fresh air and exhaust air connections of the HRV or ERV in the return air duct. Supply air from HRV or ERV must be at least 3 feet from the forced air system. Can be different from a region to another. You should check with your local code or the forced air system’s manufacturer. CAUTION The HRV and forced air system must be in continuous mode, to achieve maximum comfort and to avoid cross-contamination. Due to temperature differential between unconditioned areas and the rest of the dwelling, all ducts must be fully insulated. The unconditioned areas temperature must always be above 0°C (32°F). NOTES Fresh air must always be down-stream from the exhaust air in the return air duct of the forced air system. Installation of an HRV/ERV is not recommended for unconditioned areas (attic or crawlspace)
Exhaust at the source and supply in the return – Better
This application uses a devoted duct system for the exhausting of stale air accumulated in the home. The fresh air is dumped into the return air duct and is distributed thru the home by the existing supply air ductwork of the forced air system. Make sure when using this application that your fresh air duct connection to the forced air system return air duct is at least 3 feet from the forced air system. You should check with your local code or the forced air system’s manufacturer. The forced air system’s blower does not essentially have to run when the unit is in continuous mode, but recommended for maximum efficiency. CAUTION Insure the unit runs in conjunction with forced air system NOTE Dwellings with multiple forced air systems, we recommend one HRV/ERV per system.
Independent System installation – Best
This application uses a devoted duct system for the supply and the exhausting of stale air accumulated in the home. It is recommended to install fresh air grilles in all bedrooms and living areas. Exhaust the stale air from the bathroom, kitchen and laundry room
Determining your ventilation needs
How much fresh air do I need?
Good air quality is based on the capacity of the home’s ventilation system. Usually, the HRV’s or ERV’s capacity is measured in CFM (Cubic feet per minute) or L/s (Liters per second) of fresh air being distributed in the living space. The Room Count Calculation or the Air Change per Hour Method shows you how to determine your ventilation needs.
Download the Room Count Calculation & Air Change per Hour Methods (pdf)
Maintenance and Troubleshooting
When should I service HRV/ERV?
WARNING: ALWAYS UNPLUG HRV OR ERV DURING SERVICING
Heat/Energy Recovery Core Unit
Inside the Unit
Problem & Solutions
Air Too Humid
- Reduce the humidity level on the controller
- Verify if dryer is venting in basement
- Verify if heating wood is stored in basement
- Wait for outside temperature to change. Example: Summer can be extremely humid
- Verify balancing of the HRV/ERV
Air Too Dry
- Increase humidity level on dehumidistat
- Switch ventilation mode from continuous to intermittent
- Install an Fantech humidifier
HRV/ERV Not Running
- Verify polarization
- Verify breaker in electrical box
- Verify that dehumidistat or switch on HRV or ERV are activated to supply power to unit
- Unplug HRV or ERV verify if controller is wired correctly to the connection box on the side of the unit
- Verify low voltage box (Duotrol™) on the unit
Frequently asked Questions
This guide has been established to help the homeowner in getting the most out of his Greentek HRV/ERV.
1- Balanced Ventilation
Ventilation requirements are measured in cubic feet per minute (CFMs) of air. There are several ways to determine the right amount needed. Some rely strictly on the size of the home; others rely on the number of rooms.
The Room Count Calculation or the Air Change per Hour method shows you how to determine your ventilation needs.
The American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE) recommend a 0.35 air exchanges per hour for residential use.
Note: Always consult your local building code for minimum ventilation requirements.
Yes. This is the simplest method of installation when adding an HRV/ERV to an existing HVAC system.
Wiring diagrams and schematics are included in the installation manual. The schematics and wiring diagrams are explained in the installation manual.
Note: When the HRV/ERV is tied in to the forced air system, it is important that they run simultaneously.
Improvements in home building techniques have lead to homes being more and more airtight. Although this dramatically improved energy efficiency, it eliminated natural ventilation that occurred when air freely seeped in and out.
As all humans need fresh air, so does your home. Mechanical balanced ventilation will provide fresh air, while exhausting indoor pollutants varying from dangerous argon gasses to annoying cooking smells. It also provides a great defense against mold and excess humidity.
2- General information
Heat recovering ventilators (HRV) and energy recovering ventilators (ERV) are air-exchanging systems that reduce energy consumption when heating or cooling. The mechanical devices, equipped with fans (excluding passive units), are designed to improve air quality and help control interior humidity by drawing in fresh air while exhausting stale indoor air. The HRV is a compact unit that conditions the temperature of the outside air, while the ERV is a packaged unit that conditions both the temperature and humidity of the outside air. Because these units condition the air before it enters the home, your energy costs remain stable. This concept offers the air quality only Mother Nature can provide with efficiency levels for the 21st century.
The HRV and ERV both ventilate, the difference is in the heat-recovering core. The HRV is equipped with a polypropylene core while the ERV has a paper core. Both cores transfer sensible heat while the ERV core also transfers latent heat (humidity transfer).
The choice of an HRV and an ERV depends on the climate. The general rule is ERVs are better suited for warmer climates (Air condition more than heating) and HRVs are for colder climates.
3- Product Information
When choosing an HRV/ERV, 4 things should be considered: Capacity, efficiency, application and cost.
All Greentek and certifies HRV/ERVs are tested by the Home Ventilation Institute (www.HVI.org).
All testing procedures have been developed by HVI in order to test all aspects of an H/ERV.
4- Humidity Control
An HRV/ERV controls humidity to a certain extent. Humidity can be created many ways inside the house. Whether it be cooking, showering or simply exhaling, humidity levels can increase indoors. Ventilation will help lower the humidity by exhausting the air while drawing in the outdoor fresh air.
That said, if the air outside were more humid than the air inside, the HRV would not be able to decrease the amount of moisture contained in the indoor air.
Condensation happens when air gets cooled below its dew point. The air is no longer capable of holding moisture, so the water condensates. This normally occurs around windows because they are less insulated, therefore cooler in winter months.
Proper ventilation will reduce humidity in winter, along with constant air circulation. This will reduce condensation on the windows.
5- Operating your HRV/ERV
Greentek offers a variety of controllers for added HRV/ERV functions. We also offer a timer designed to be installed in a bathroom. This timer activates high speed for a period of 20, 40 or 60 minutes for added humidity evacuation.
The humidistat activates high speed on the HRV/ERV. It should be set in the comfort zone during heating periods, and turned off during the summer.
The reason behind this is air tends to be more humid in the summer. If the air outside is more humid than the air inside, the HRV/ERV won’t be able to dehumidify.
Some Wall controllers have an LED light. An orange light indicates the unit is powered while a green light indicates the unit is in high speed.
An HRV/ERV is a mechanical ventilation machine required when natural ventilation isn’t available. If windows are left open during the summer, running the HRV/ERV is not necessary.
Re-circulation means that the HRV/ERV draws air from inside the house and re-distributes it. No outside air enters the house. This can be activated with the wall controls (EHC1.5 DC; RD-3D or RD-4D).
This feature can be useful on extreme cold days when fresh air isn’t needed. The heating load on your house will be reduced and that’s money in your pocket.
6- Efficiency terms for HRV/ERV’s
Apparent Sensible Effectiveness (ASE): The measured temperature rise of the supply air stream divided by the difference between the supply temperature (point 1) and exhaust temperature (point 3) and multiplied by the ratio of mass flow rate of the supply divided by the minimum of the mass flow rate of the supply or exhaust streams. This value is useful principally to predict final delivered air temperature at a given flow rate.
Sensible Recovery Efficiency (SRE): The sensible energy recovered minus the supply fan energy and preheat coil energy, divided by the sensible energy exhausted plus the exhaust fan energy. This calculation corrects for the effects of cross-leakage, purchased energy for fan and controls, as well as defrost systems. This value is used principally to predict and compare energy performance.
Total Recovery Efficiency (TRE): The total energy (enthalpy) recovered minus the supply fan energy and the preheat coil energy, divided by the total energy (enthalpy) exhausted plus the exhaust fan energy. This calculation corrects for the effects of cross-leakage and external purchased energy for fans and controls. It is used principally to predict and compare energy performance.
7- The Greentek Warranty
- 10-YEAR LIMITED WARRANTY ON VENTILATION MOTORS ((XPH-Series; XDH7.15; PH-ES Series; PH Series and PE-Series)) – Greentek warrants the ventilation motors against defects in material and workmanship for a period of ten years from the date of original installation. Greentek will provide a new or remanufactured part, at its own discretion, to authorize replacement of defective part, without charge for the part itself.
- 5-YEAR LIMITED WARRANTY ON VENTILATION MOTORS (C3.14 & SS3.80 Series) – Greentek warrants the ventilation motors against defects in material and workmanship for a period of five years from the date of original installation. Greentek will provide a new or remanufactured part, at its own discretion, to authorize replacement of defective part, without charge for the part itself.
- LIFETIME LIMITED WARRANTY ON POLYPROPYLENE HEAT RECOVERY CORE – Greentek warrants the polypropylene heat recovery core against defects in material and workmanship for a lifetime from the date of original installation. Greentek will provide a new or remanufactured part, at its own discretion, to authorize replacement of defective part, without charge for the part itself.
- 5-YEAR LIMITED WARRANTY ON ENTHALPY ENERGY RECOVERY CORE – Greentek warrants the enthalpy energy recovery core against defects in material and workmanship for a period of five years from the date of original installation. Greentek will provide a new or remanufactured part, at its own discretion, to authorize replacement of defective part, without charge for the part itself.
- 1-YEAR LIMITED WARRANTY – Greentek warrants replacement parts that have been replaced after the standard period of the previous limited warranty, to be free from defects in material and workmanship. If a defect is found within one year from date of original installation of replacement part, (whether or not actual use begins on that date) Greentek will provide a new or remanufactured part, at its own discretion, to authorize replacement of defective part, without charge for the part itself.
WARRANTY CONDITIONS – Warranties apply only to Greentek products installed in their original location. Installation, use, care, and maintenance must be normal and in accordance with instructions contained in the Owner’s Manual and service information. Defective parts must be returned to the distributor through a registered servicing dealer for credit. All work shall be performed by a certified technician.
- GREENTEK WILL NOT BE RESPONSIBLE FOR – Normal maintenance, installation, including filter cleaning and/or replacement, damage or repairs required as a consequence of faulty installation, misapplication, abuse, improper servicing, unauthorized alteration or improper operation. Damage as a result of floods, winds, fires, lightning, accidents, corrosive environments or other conditions beyond the control of Greentek. Parts not supplied or designated by Greentek, or damages resulting from their use
8- HRV/ERV Maintenance
Filters can be cleaned with a vacuum or wash. We recommend cleaning them four times a year.
Hint: The filter on the intake side (left side) will accumulate more dirt than the exhaust filter. To extend their lives they can be swapped after a certain period of time.
Once a year or as needed, vacuum all 4 sides and soak in warm water for 15 minutes. Then Rinse the core with shower head or hose without scrubbing. Then let it either air dry or use a hair dryer. If you clean your core during the cold season, please make sure that the core is completely dry before reinstalling.
Inside of the cabinet should be washed using a damp cloth and mild non-abrasive soap. We recommend using an environmentally friendly cleaner.
Greentek HRV/ERV are equipped with sealed motors. No preventative maintenance is required on any mechanical part. The home owner must only assure that the unit is clean.