HVAC-HRV ENG 3/10/03 10:10 am Page 1 Heat Recovery Ventilator
00-211 english booklet 3/20/03 12:00 pm Page i Heat Recovery Ventilator Produced by Natural Resources Canada’s Office of Energy Efficiency EnerGuide The Home Heating and Cooling Series is published by Natural Resources Canada’s Office of Energy Efficiency’s EnerGuide programs.
00-211 english booklet 3/20/03 12:00 pm Page ii National Library of Canada cataloguing in publication data Main entry under title : Heat recovery ventilator Issued also in French under title: Ventilateurs-récupérateurs de chaleur. Cover title. Previously issued 2000 under title: Operating and maintaining your heat recovery ventilator (HRV). ISBN 0-662-33772-7 Cat. no. M91-23/8-2003E 1. Heat exchangers – Handbooks, manuals, etc. 2. Heat recovery – Equipment and supplies – Handbooks, manuals, etc. 3.
00-211 english booklet 3/20/03 12:00 pm Page 1 Table of Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 The Need for Mechanical Ventilation . . . . . . . . . . . . . . . . . . 3 Cleaning the Air in an R-2000 Home . . . . . . . . . . . . . . . . . . Cleaning the Air in a Conventional Home . . . . . . . . . . . . . . Some Typical Household Pollutants . . . . . . . . . . . . . . . . . . . How Much Ventilation Does Your Home Need? . . . . . . . . .
00-211 english booklet 3/20/03 12:00 pm Page 2 I NTRODUCTION The importance of ventilation in today’s more energyefficient homes is universally recognized. Introduced as a requirement for airtight R-2000* homes, continuous ventilation systems are now common in new conventional housing and major home renovations. Because of the energy savings generated, the system of choice is often a heat recovery ventilator (HRV).
00-211 english booklet 3/20/03 12:00 pm Page 3 T HE N EED FOR M ECHANICAL V ENTILATION Cleaning the Air in an R-2000 Home R-2000 homes are built to be extremely airtight. This limits the uncontrolled flow of air in and out of the home and greatly reduces heat loss and moisture damage to the building structure.
00-211 english booklet 3/20/03 12:00 pm Page 4 random and does not always provide adequate ventilation, which is just as important in a conventional home as in an R-2000 home. Even when there is an acceptable rate of air exchange, the fresh air may not be getting to the rooms where it is needed. As a result, mechanical ventilation is needed in many conventional homes in order to evenly distribute fresh air throughout the home and maintain a healthy living environment.
00-211 english booklet 3/20/03 12:00 pm Page 5 Some Typical Household Pollutants You can eliminate or reduce certain sources of indoor air pollution by understanding where household pollutants come from. However, no matter how careful you are, there will always be some pollutants in your home and, therefore, a need for ventilation. Table 1 identifies the most common pollutants and their sources.
00-211 english booklet 3/20/03 12:00 pm Page 6 How Much Ventilation Does Your Home Need? The capacity of a home’s ventilation system is usually based on the number of rooms in the house. HRV capacity is measured in litres per second (L/s) or cubic feet per minute (cfm) of fresh air provided to the home. Using the information in Table 2, you can calculate how much fresh air is needed under normal circumstances to maintain good air quality in your home.
00-211 english booklet 3/20/03 12:00 pm Page 7 T HE HRV S YSTEM Components of an HRV System An HRV system generally consists of the following equipment: • insulated ducts for incoming (fresh) and outgoing (stale) air, along with exterior hoods; • ductwork to distribute fresh air throughout the home and to return stale air to the HRV; • fans to circulate air throughout the home and to exhaust stale air to the outdoors; • a heat-exchange core, where heat is transferred from one air stream to the other; •
00-211 english booklet 3/20/03 12:00 pm Page 8 During the heating season, an HRV recovers heat from the outgoing, stale household air and uses it to preheat incoming, fresh outdoor air. The HRV then distributes the incoming air throughout the house. In the example shown in Figure 1, the flow of air in and out of the house takes place simultaneously (note: the path of the airflow may vary from one type of HRV to another). The two air streams are always kept separate within the HRV.
00-211 english booklet 3/20/03 12:00 pm Page 9 Air Distribution There are two standard ways to distribute fresh air throughout the home – through ductwork installed specifically for the HRV (direct ductwork) or through the ductwork of a forced-air furnace system. A direct-ducted system is commonly found in homes that do not have forced-air heating, such as those with electric baseboard, hot water or radiant heating.
00-211 english booklet 3/20/03 12:00 pm Page 10 An HRV can also be installed to work in conjunction with a forced-air furnace system, as illustrated in Figure 3. In this case, the HRV’s fresh-air duct is connected to the furnace’s main return air duct. The fresh air enters the furnace and is distributed throughout the house using the regular system of ductwork.
00-211 english booklet 3/20/03 12:00 pm Page 11 Checking Airflow Room by Room As a general rule, a direct-ducted system should provide at least as much airflow per room as shown in Table 2 on page 6. An HRV system connected to a forced-air furnace distributes the fresh ventilation air to each warm air supply duct proportionally.
00-211 english booklet 3/20/03 12:00 pm Page 12 The Need for a Balanced System HRVs are designed to operate in a balanced state – the same amount of air should be drawn into the home as is being exhausted. An unbalanced system results in poor airflow and poor heat recovery and can lead to other problems, including an undesirable, continuous air-pressure difference between the inside and outside of your home.
00-211 english booklet 3/20/03 12:00 pm Page 13 Finding a Contractor to Service Your HRV To find a qualified HRV contractor, look under Heating Contractors or Ventilating Contractors in the Yellow Pages™. When you contact one of the companies listed, make it clear that you require the services of a residential mechanical ventilation installer who has been certified by the Heating, Refrigerating and Air Conditioning Institute (HRAI) of Canada.
00-211 english booklet 3/20/03 12:00 pm Page 14 Although your HRV should have been balanced during installation, it is a good idea to have the system checked by a qualified contractor once a year. If you are purchasing an existing home that is equipped with an HRV, consider having the system serviced, including a balance test. Do-It-Yourself Balance Check You can perform your own rough check of your HRV’s airflow balance using the plastic trash bag technique explained on page 11.
00-211 english booklet 3/20/03 12:00 pm Page 15 The operating controls may include the following functions depending on the installation and the HRV model: • high-speed and low-speed controls; • a circulation mode setting, which circulates air inside the home but does not exchange indoor and outdoor air; • a dehumidistat that will trigger the HRV into highspeed operation when the humidity level in your home reaches a pre-set level; • a timer, which can be set to run the HRV at high speed for specified i
00-211 english booklet 3/20/03 12:00 pm Page 16 High-Speed Operation Under certain conditions, the ventilation rate in your home may need to be increased from low-speed operation. Depending on the installation, a high-speed cycle may be triggered manually or by a timer, dehumidistat or other controls. High-speed operation is often needed in the kitchen and bathrooms.
00-211 english booklet 3/20/03 12:00 pm Page 17 Considerations for Heating Season Operation Most HRVs feature an automatic defrost mode that activates when the temperature of the incoming fresh outdoor air is below -5°C.
00-211 english booklet 3/20/03 12:00 pm Page 18 You may find that operating the HRV keeps the home cooler and quieter than opening windows for ventilation. Keeping windows closed also provides better security and reduces the amount of pollen and dust entering the home. Some modern HRVs give you the option to turn off the low-speed setting. Even with this setting turned off, the HRV can still be set at high speed to remove excess moisture and odours from the kitchen and bathrooms.
00-211 english booklet 3/20/03 12:00 pm Page 19 Seven-Step Maintenance Schedule With routine preventative maintenance, you can avoid unnecessary problems, ensure the effectiveness of your HRV, and prolong its life. The summary below indicates some general HRV maintenance requirements. Items 1 through 6 are maintenance procedures a homeowner should undertake between annual service visits by a professional.
00-211 english booklet 3/20/03 12:00 pm Page 20 FIGURE 5 Example of location of filters in an HRV INTERIOR OF THE HOME Filter Fresh air to House Stale air from House Filter (Note: Other types of filters are used in some HRVs, and their location may vary.) OUTDOORS yy ;; yy ;; ;; yy Screen 2. Clear the exterior intake and exhaust vents of obstructions. Check the outside vents regularly to ensure that the screen openings are not obstructed by grass, bushes, leaves or other debris (see Figure 6).
00-211 english booklet 3/20/03 12:00 pm Page 21 3. Clean the heat-exchange core. Inspect the heat-exchange core twice a year and clean it as required (consult your owner’s manual for instructions on inspecting and cleaning the core). A build-up of dust and dirt can restrict airflow and reduce the efficiency of your HRV. After inspection and cleaning, make sure the core is replaced right-side-up.
00-211 english booklet 3/20/03 12:00 pm Page 22 5. Service the fans. The fans on many HRVs are designed to operate continuously without lubrication. Your owner’s manual will indicate whether lubrication or service is necessary. If lubrication is required, make sure you use proper motor lubricating oil (non-detergent oil). Do not use too much oil, as this may damage the motor.
00-211 english booklet 3/20/03 12:00 pm Page 23 The HRV’s annual servicing should include the following: • maintenance items 1 to 6 (above). Additional requirements specified by the manufacturer should also be included. • a general check for proper operation. Controls and electrical connections in the HRV should be inspected, particularly those located inside the exhaust and fresh air streams. The defrost system should also be tested.
00-211 english booklet 3/20/03 12:00 pm Page 24 HRV M AINTENANCE C HART Unless otherwise recommended by the manufacturer, service your HRV according to the following schedule. If service or maintenance items not specified below are recommended by the manufacturer, write them into the blank spaces provided. CAUTION! DISCONNECT ELECTRICAL POWER BEFORE SERVICING YOUR HRV.
00-211 english booklet 3/20/03 12:00 pm O PERATING P ROBLEMS S OLUTIONS Page 25 AND As with any appliance, problems can arise with your HRV, even if it is operated according to the manufacturer’s instructions. Some problems will be very simple to diagnose and remedy, while others may require the services of a qualified contractor. The following HRV Troubleshooting Guide indicates when a contractor should be called. For more specific information, consult your owner’s manual.
00-211 english booklet 3/20/03 12:00 pm Page 26 Problem Possible causes and solutions HRV runs on one speed only • Check all switches for malfunctions by varying the settings. • If unit remains on same speed, call a contractor. Damaged duct insulation jacket • If the insulation is wet, has any ice build-up or if there is water on the floor, replace and properly seal the damaged insulation. • If the insulation is not damaged, use duct tape to repair any punctures in the jacket.
00-211 english booklet 3/20/03 12:00 pm Page 27 N EED M ORE I NFORMATION ? Order Free Publications From the OEE The Office of Energy Efficiency (OEE) of Natural Resources Canada offers many publications that will help you understand home heating systems, home energy use and transportation efficiency. These publications explain what you can do to reduce your energy use and maintenance costs while increasing your comfort and helping to protect the environment.
00-211 english booklet 3/20/03 12:00 pm Page 28 The EnerGuide label, which is affixed to all new major electrical household appliances and room air conditioners, helps you compare the energy ratings of all models sold in Canada. EnerGuide ratings are also listed in the OEE’s annual directories of major electrical household appliances and room air conditioners.
00-211 english booklet 3/20/03 12:00 pm Page 29 To receive any of these free publications, please write or call: Energy Publications Office of Energy Efficiency Natural Ressources Canada c/o S.J.D.S. Ottawa, Ontario K1A 1L3 Fax: (819) 779-2833 Toll-free: 1 800 387-2000 In the National Capital Region, call 995-2943. Please allow three weeks for delivery. Publications can also be ordered or viewed on-line at the OEE’s Energy Publications Virtual Library: http://oee.nrcan.gc.ca/infosource.
00-211 english booklet 3/20/03 12:00 pm Page 30 If you cannot find a qualified contractor in the Yellow Pages™, a list of residential mechanical ventilation installers in your area is available by contacting Heating, Refrigeration and Air Conditioning Institute of Canada 5045 Orbitor Drive Building 11, Suite 300 Mississauga, ON L4W 4Y4 Fax: (905) 602-1197 Web site: http://www.hrai.
00-211 english booklet 3/20/03 12:00 pm Page 31 HRV/ERV Manufacturers Manufacturer Brand Name Address Telephone Number Carrier Canada Carrier 1515 Drew Road Mississauga, ON L5S 1Y8 (905) 405-4065 Honeywell Limited Honeywell 35 Dynamic Drive Scarborough, ON M1V 4Z9 (416) 332-3306 Imperial Air Technologies Greentek 500 Ferdinand Boulevard Dieppe, NB E1A 6B9 (506) 859-9908 Kanalflakt Canada Inc.
00-211 english booklet 3/20/03 12:00 pm NOTES 32 Page 32
00-211 english booklet 3/20/03 12:00 pm Page 33 33
HVAC-HRV ENG 3/10/03 10:10 am Page 2 Leading Canadians to Energy Efficiency at Home, at Work and on the Road The Office of Energy Efficiency of Natural Resources Canada strengthens and expands Canada's commitment to energy efficiency in order to help address the challenges of climate change.
