ENERGY STR Homes Northwest Performance Testing Field Guide Cover photos Left, center: Conservation Services Group, Inc.; Right: The Energy Conservatory. Used with permission.
cknowledgements cknowledgments Funding for this guide was provided by the Northwest Energy Efficiency lliance ( the lliance ), a non-profit corporation supported by electric utilities, public benefits administrators, state governments, public interest groups and energy efficiency industry representatives. These entities work together to make affordable, energy-efficient products and services available in the marketplace. Thanks to the lliance Technical Committee for their work on this guide. Primary technical review provided by ruce Harley, Conservation Services Group (CSG). dditional technical review by David aylon, Dan Cote, David Hales, Jeff Harris, David Hutchins, and rady Peeks. ENERGY STR and the ENERGY STR Logo are registered trademarks of the United States Environmental Protection gency and the U.S. Department of Energy.
Contents 1 2 3 4 5 6 Introduction 1 Testing & Reporting Overview 3 Duct System Design & Testing 7 Combustion ppliance Zone (CZ) Test 21 lower Door Testing 27 HVC Start Up Testing 31 1 2 3 4 5 6 Glossary C Glossary of Terms 35 ppendix Program Forms: Duct Label 37 ppendix HRV Installation Guidelines 39 ppendix C Zone Pressure Relief Guidelines 41 Glossary C
Introduction 1 Introduction 1 Introduction ENERGY STR Homes Northwest promotes the construction of some of the highest performing homes built in the U.S. today. Sponsored by the Northwest Energy Efficiency lliance (the lliance) and utilities throughout the Pacific Northwest, the ENERGY STR Homes Northwest program includes higher insulation levels, ENERGY STR qualified mechanical systems, windows, lighting, and appliances. Perhaps the most critical features, however, are related to the heating and cooling systems. In addition to higher equipment efficiencies, ENERGY STR Homes Northwest requires that all duct systems be performance tested to assure minimal leakage. dditionally, all heat pumps must be properly sized, and air flow and refrigerant charge field verified as correct. This represents a significant portion of the home s energy savings, and testing ensures that those savings are legitimate and will persist over time. In order to accomplish this, the program will identify and promote trained, certified contractors able to market and deliver this premium professional service. The ENERGY STR Homes Northwest program adopted the testing procedures for performance testing created by the Regional Technical Forum (RTF) and promoted as Performance Tested Comfort Systems (PTCS). This guide is designed to provide all relevant information to prepare Performance Testers to qualify as ENERGY STR Homes Northwest program-approved contractors. The program will maintain an up-to-date list of all individuals that have been approved to conduct performance testing in the new construction market. It is anticipated that HVC contractors will be the most likely trade offering this service, but Verifiers, uilding Science Specialists, Utility staff, and others are eligible as long as they meet the necessary criteria. Only technicians on this list will be able to conduct testing and provide results sufficient for program compliance. The purpose of this list is to ensure that builders are directed to certified 1
Introduction 1 Introduction technicians with proven skills to conduct performance testing for new construction. The list will be available through uilder Outreach Specialists and Verifiers, and at www.northwestenergystr.com. The criteria a technician must meet to become certified are as follows: 1.Duct and combustion appliance testing: Technicians must attend an approved training and be certified by an RTF-approved trainer. 2.Refrigerant charge and air-flow: The RTF has approved both the Honeywell Service ssistant and Proctor Engineering s CheckMe! Program as compliant testing protocols for heat pump installations. Certified contractors trained may use either method to prove compliance with program standards. For equipment with TXV metering devices on the indoor and outdoor coil, an alternative path is available to document the refrigerant charge test. 3.Envelope tightness testing: Technicians conducting blower door tests must be trained through an eligible training program. The State Certification Organizations (SCOs) will provide lists of eligible training programs from which contractors can be qualified. 2
Testing & Reporting 2 Testing & Reporting Overview 2 Testing & Reporting Overview 2.1 Testing asics Ducts Duct leakage is measured in Cubic Feet per Minute (CFM) at 50 Pascals (Pa) also known as CFM50. The result of the test must be less than 6% of the conditioned floor area (CF) of the home in square feet. (There are exceptions to the 6% limit; see page 9.) The requirement is never less than 75 CFM50, so a home of less than 1250 square feet would have a maximum duct leakage of 75 CFM50. If there are multiple systems in a house, each system must test at less than 6% of the floor area served by that system. Documentation of the results must be provided to the program Verifier. Duct leakage testing can be accomplished with a duct pressure tester, typically a Duct laster, and can be done in either of two ways: the total leakage test, or the leakage to the exterior test. The standard is the same for both, 6% of conditioned floor area, or 75 CFM50, whichever is greater. Details of these two tests are covered in Chapter 3. Combustion ppliances Each room, space, or area of the home that has one or more combustion appliance(s) must have a Combustion ppliance Zone Pressure test, or CZ test. The CZ test checks for negative pressures induced by imbalances or leaks in the duct system (or exhaust fans or appliances), that may be large enough to cause backdrafting. ackdrafting is a failure mode of combustion appliances that can include spillage of flue gases from the appliance, drawing them down the vent or chimney, flame rollout, and/or carbon monoxide production. Pressures more negative than 3 Pascals 3
Testing & Reporting (Pa) in any combustion appliance zone are considered risky and are not allowed in the ENERGY STR Homes Northwest program. 2 Testing & Reporting Overview CZ zones include any space(s) that has (have) a furnace, boiler, water heater, gas fireplace, or wood stove used for primary space or water heating. (Decorative fireplaces are excluded.) Note that any sealed combustion equipment (all combustion supply air and venting is isolated from the house air by sealed ductwork) need not have a CZ depressurization test. Details of the CZ test are covered in Chapter 4*. Refrigerant Charge Heat pumps depend on having the correct amount of refrigerant charge. If the charge is too high or too low, the efficiency of the system suffers sometimes dramatically. Manufacturers recommend certain standard operational tests when installing a new central air conditioner or heat pump to ensure the right charge level (typically, the sub-cooling test or the superheat test, depending on the type of system). For all heat pumps, charge testing must be accomplished and documented with an approved proprietary system for the ENERGY STR Homes Northwest certification. Proctor Engineering Group s CheckMe! and Honeywell s Service ssistant are approved systems, and others may be approved for the ENERGY STR Homes Northwest program. Exception (may be allowed at the discretion of the SCO): heat pumps with TXV metering devices on the indoor and outdoor coil may document the charge test without the use of CheckMe! or the Service ssistant. copy of the documentation or paperwork from whichever method is used must be turned in to the Verifier for ENERGY STR certification. Details of the charge testing are covered in manufacturer s literature and in the required training for use of CheckMe! or the Service ssistant. Note that neither method actually gives an answer in CFM; the CFM result must still be noted and shown to meet the requirement. ir Flow Central air conditioners and heat pumps also depend on having the correct amount of air flowing over the indoor coil for proper operation. Low air flow can hurt the efficiency of the system, sometimes dramatically. The ENERGY STR Homes Northwest program requires air flow between 350 and 400 cubic feet per minute (CFM) for each ton of rated capacity (1 ton = 12,000 btu/hour). 4 *For compliance with Oregon State Tax Credit requirements, additional air-handler induced pressurization tests may be required.
Testing & Reporting ll heat pumps (with certain exceptions) must have air flow tested with the TrueFlow meter or duct tester, or using the temperature split method. Proctor Engineering Group s CheckMe! accepts input from the TrueFlow meter (preferred) and can also use temperature split. The Service ssistant Hand Tool depends on temperature split, although the TrueFlow meter or duct tester is still recommended to improve accuracy. Details of air flow testing are covered in the instructions for the TrueFlow meter and in the required training for use of CheckMe! or the Service ssistant. 2 Testing & Reporting Overview lower Door Test blower door tests the building enclosure for air tightness. y depressurizing the structure with a powerful fan and measuring the air flow across the fan, the air tightness of the building is determined. Homes using the Northwest OP 2 (electric resistance, propane, or oil) must be tested with a blower door to qualify for the ENERGY STR Homes Northwest program. They must achieve 2.5 ir Changes per Hour (CH) or less, when measured at 50 Pascals (Pa). Details of the blower door test are covered in Chapter 5. Homes using OP 1 may also be tested, at the discretion of the SCO; the maximum air leakage allowed for OP 1 is 7 CH at 50 Pa. 2.2 Testing Matrix The following table shows the range of house types that may be certified in the ENERGY STR Homes Northwest program, and the tests that are required for each. State Certification Organizations may require additional testing beyond those described in the table in order to access utility incentives. Housing Type Gas Furnace Duct Leakage Yes CZ Yes 1 Refrigerant Charge No irflow No lower Door No Heat Pump Yes Yes 2 Yes Yes No Electric Resistance Oil or Propane Furnace Hydronic Heat n/a Yes n/a Yes 2 Yes 1 Yes 1 n/a No n/a n/a No No Yes Yes No 1 Except where combustion equipment has sealed outdoor air supply and venting system. Oregon State Tax credit require ments may require additional testing. 2 If combustion equipment (i.e., fireplace or wood stove) is present and used as the primary space or water heating system. Oregon State Tax credit requirements may require additional testing. 5
Testing & Reporting 2 Testing & Reporting Overview 2.3 Reporting and Q/QC Process The verification and certification process established for ENERGY STR Homes Northwest is administered by State Certification Organizations (SCO), which train and certify Verifiers to confirm each home meets regional standards. The SCOs are also responsible for the Quality ssurance (Q) process. The Verifier will directly confirm the proper selection and installation of specifications with nominal values and labels (e.g., insulation, windows, appliances). For the performance testing standards, the Verifier will be responsible for confirming that the performance testing technician is approved by the program, and will collect the relevant testing documentation for each home. In most cases the Verifier will not directly test the systems or homes. The Verifier will record the data from the performance testing sticker (see ppendix ) applied to the air handler on the inspection form, and will enter this information in the program database. For CheckMe!, Honeywell Service ssistant, or the TXV Exception, a copy of the report will need to be provided to the Verifier by either the technician or the builder. s part of the performance technician s ongoing participation in a quality control program administered by an RTF-approved training and certification organization, any work completed and resulting data may be subject to independent verification or testing. In addition to this third-party Quality Control (QC), the SCOs will conduct Q of the entire certification process, including independent performance testing of the systems. dditional information on the SCO s Q process can be found at www.northwestenergystr.com. 6
Duct Systems 3 Duct System Design & Testing 3 Duct Systems Design & Testing 3.1 Design and Installation Requirements It is recommended that ductwork for all system types be designed and installed in accordance with recommended industry practice as outlined in ir Conditioning Contractors of merica (CC) publications or merican Society of Heating, Refrigerating, and ir Conditioning Engineers (SHRE) handbooks. There is no program requirement to submit documentation of duct design, but installation shall meet the following requirements. dditional requirements for heat pump design and installation are in ppendix C. Detailed requirements can be found in the ENERGY STR Homes Northwest Specifications and Technical Reference on the www.northwestenergystr.com website. Duct systems must be designed, sized, and installed using recognized industry standards so that calculated heating and/or cooling capacities are delivered to each zone. Unlined building cavities shall not be used as ducts to convey return or supply air. ranch out runs shall be a minimum of 6 inches in diameter except to bathrooms. Pressure relief return air pathways shall be provided for rooms that have supply registers and no returns (or inadequate returns). Pressure relief can include return ducts, pass-through grilles, pressure-relief ducts, door undercuts, or similar devices. The limit of pressurization for these zones is 3 Pa (with reference to the outside), and testing for this limit is optional. ll duct joints and connections shall be mechanically fastened with 7
Duct Systems 3 Duct Systems Design & Testing screws. Flexible ducts shall be attached using nylon/plastic straps tightened with a manufacturer approved tool (hand tightening is not acceptable) or stainless steel worm drive clamps. Mastic and/or tape of any kind shall not be used as mechanical fasteners. Ducts shall be cut to proper length supported in such a manner as to prevent air flow constriction. ll rigid metal ducts and plenums outside the heated space shall be insulated to at least R-8, with an approved vapor barrier installed on the outside surface of the insulation. pproved tape may be used at insulation seams to provide a continuous vapor barrier. ll flexible HVC ducts outside the heated space shall have an ir Diffusion Council (DC) certified minimum R-value of R-8. ll ducts and plenums that are internally lined with insulation outside the heated space shall be installed in accordance with the SMCN Duct Liner pplication Standard, Second Edition. The total R-value of this duct work shall be no less than R-8. ll HVC ducts routed within exterior wall cavities shall be insulated to a minimum of R-14 between the duct and the exterior wall sheathing. ll duct insulation shall be installed and supported using mechanical fasteners such as permanent plastic straps or nylon twine (not tape). ll HVC supply and return ducts, air handlers, and plenums shall be sealed with approved mastic at all joints and corners, including prefabricated joints; longitudinal seams need not be sealed unless they are damaged. UL181-M or UL181-M mastic shall be used on rigid metal ducts, UL 181-M mastic on flex ducts. Tape may be used only on operable service panels such as the air handler cabinet. Duct leakage tests shall be documented and documentation shall be provided to the Program Verifier (see section 3.2). ir filters shall be installed in the return air system in a location that will be easily accessible to the user for filter servicing and in a position where all return air and outside air will pass through the filters before crossing the indoor coil or heat exchanger. Filters should not be installed in crawl spaces, and should only be in attic areas that are easily accessible for service. 8
Duct Systems 3.2 Duct Diagnostic Tests Leakage Requirements Certification of a duct system under the ENERGY STR Homes Northwest program requires that one or more of these tests are performed on each system. n approved ENERGY STR Homes Northwest performance testing technician shall complete the testing and certification process and shall provide documentation of the test results showing compliance with standards to a Program Verifier. Tested duct leakage shall not exceed 0.06 CFM50 x floor area served by the system (in square feet), or 75 CFM50, whichever is greater. See exceptions below. Either the Total Duct Leakage Test or the Duct Leakage to the Exterior Test may be used. 3.2.1 Total Duct Leakage Test When to Test This test is most appropriate in new construction when ducts are to be tested at the rough-in stage before the drywall is hung. The test measures the CFM50 value of the duct system. The test shall be performed with a duct tester and a calibrated digital manometer. ecause this test measures the total leakage, including leaks to the interior space, the leakage may be higher than shown by the leakage to exterior test. Leakage to the exterior is the primary concern regarding the energy usage of the home, and thus the total leakage test may be unnecessarily conservative (showing higher leakage). However, the benefit of being able to test at the rough-in stage (when corrections can be made easily) may outweigh this drawback in most cases. lso, the blower door is not needed for this test. IMPORTNT: 1)The air handler must be present before this test is performed. However, there are two exceptions. These exceptions apply only to the factory-supplied air handler itself in any case, all field-installed plenums, plenum sleeves, and other air-side devices must be in place when the duct leakage is tested. a. If the air handler is completely contained in the conditioned space of the home, the system may be tested without it. In that case, the supply and return systems would be tested separately according to the procedure, and the sum of the two halves would be considered the total duct leakage. b. The test may be conducted without the air handler in place provided that the maximum allowed leakage is reduced to 0.04 x floor area served, or 50 CFM, whichever is larger. (Example: for a 2000 3 Duct Systems Design & Testing 9
Duct Systems 3 Duct Systems Design & Testing square foot home, the allowed duct leakage would normally be 0.06 x 2000 = 120. When tested without the air handler, it would be 0.04 x 2000 = 80). 2) total leakage testing at rough-in should be supplemented by a visual inspection on at least a spot-check basis. When the total leakage test is done at rough-in, one potential significant leak that cannot be tested is the register boot-to-drywall (or to-subfloor) connection. When the boot is installed in a ceiling, wall, or floor bordering an unconditioned buffer space (attic, crawlspace) or a building cavity that is connected to outside, this boot-to-drywall or sub floor connection can be a significant leak. In addition, if the air handler was not present during the leakage test, a visual check to address the sealing of the plenum-to-air handler connection should be made. Tools and Equipment: Duct tester Manometer with tubing and static pressure probe Masking tape and paper, foam blocks, and/or duct mask to seal registers Setup: Remove air filter(s) from the air handler. Close the filter cover if applicable. Open all duct dampers (Note setting and return after testing). ttach the duct tester to the air handler cabinet if possible this is the preferred location. s an alternate, set up at the return grille nearest to the air handler (this does not work well if the return system is very leaky). Set the fan to pressurize the ducts. ttach a hose from the fan pressure tap to the reference tap on channel of the manometer. (Important note: if you choose to depressurize the ducts, rather than pressurize, the duct tester fan setup requires the flow conditioner, one of the low-flow rings, and an extra reference pressure tube. Consult the duct tester manual for details.) Seal all the duct system supply and return registers with tape, paper, foam blocks, or duct mask. Make sure any integrated outside air intakes for ventilation are closed. Place the duct pressure probe in the supply register closest to the air handler facing the direction of flow, or place the duct pressure tube in the supply plenum. ttach it to the input tap on channel of the manometer. Open an exterior door or window so that all spaces exterior to the ducts are at outside pressure. 10
Duct Systems Total Duct Leakage 1. With the Duct Tester, pressurize the ducts to +50 Pa WRT outdoors (Channel ) H + 50. Open exterior door or window 3 Duct Systems Design & Testing Test: 1. With the Duct Tester pressurize the ducts to +50 Pa with respect to (WRT) outside. If you can t reach +50 Pa, perform the test at the highest attainable pressure (rounded to the nearest 5 Pa) and correct the results (see Interpreting Results on page 12). Total Duct Leakage 2. Read the fan pressure (Channel, red) H + 87. Open exterior door or window 2. Read and record the fan pressure. Set the manometer for the correct ring configuration, and read and record the CFM of fan flow. This is the CFM50 leakage of the system. If the fan pressure is less than 30 11
Duct Systems (if the fan flow reading blinks), turn off the fan and install a smaller low flow ring, so that the fan pressure is higher than 30, and re-take the test. 3 Duct Systems Design & Testing Total Leakage Test (Duct tester outside conditioned space) This test is the same except the duct testing location is slightly different. See the diagram below. 1. With the Duct Tester pressurize the ducts to +50 Pa WRT to outside. If you can t reach +50 Pa, perform the test at the highest attainable pressure (rounded to the nearest 5 Pa) and correct the results (see Interpreting Results below). Total Duct Leakage (alternate) + 50 1. With the Duct Tester, pressurize the ducts to +50 Pa WRT outdoors. (Channel ) Example 2. Duct Tester (DT) hooked up at air handler. DT is outside conditioned space Open exterior door or window 2. Read and record the fan pressure. Set the manometer for the correct ring configuration, and read and record the CFM of fan flow. This is the CFM50 leakage of the system. If the fan pressure is less than 30 (if the fan flow reading blinks), turn off the fan and install a smaller low flow ring, so that the fan pressure is higher than 30, and re-take the test. Interpreting Results: The CFM50 is a measure of the total collected hole size in the system. s an approximation the CFM50 divided by 10 gives the total effective leakage area in square inches. 12
Duct Systems Example: 400 CFM50/10 = 40 square inches of total leakage area Using this approximation during sealing can help estimate how many and how big the holes are that you are looking to seal. If you could not perform the test at +50 Pa, do the test at the highest duct pressure you can achieve (that is a multiple of 5 Pa) and adjust your results using Table 1 below. Table 1: Can t Reach Pressure (CRP) Correction Factors Duct Pressure 10 15 20 25 30 35 40 45 CRP Factor 50 Pa 2.85 2.19 1.81 1.57 1.39 1.26 1.16 1.07 3 Duct Systems Design & Testing Example: The results of the test show a leakage area of 275 CFM at a duct pressure of 35 Pa. The correction factor from Table 1 for a pressure of 35 Pa is 1.26. 275 CFM35 x 1.26 = 346.5 CFM50 The test doesn t give any indication of where to find the holes, just an estimate of the collected hole size, and qualification for the pass/fail criteria. s CFM50 values get larger, they will tend to be less accurate. In the range of values required for certification, the test should be the most accurate. Diagnostics to find leaks include visual inspection, feeling for leaks from pressurized ducts, and theatrical smoke blown into the intake of the duct tester. dditionally, supply leakage may be isolated from return leakage by blocking the filter rack, to measure the CFM50 of only the return side (or supply, depending on the setup and location of the filter.) 13
Duct Systems 3 Duct Systems Design & Testing 3.2.2 Duct Leakage to the Exterior Test When to Test In order to conduct this test, drywall, exterior doors, and windows must be installed, and the building envelope must be capable of maintaining +50 Pa, with respect to (WRT) outside pressure with the operation of a blower door. y pressurizing the interior of the home with a blower door while using a duct tester, duct leakage to the interior is zeroed out and eliminated from the measurement. The test measures the CFM50 value for holes in the duct system outside of conditioned space. The test shall be performed with an approved duct tester and a calibrated digital manometer. This test is most appropriate in new construction when ducts are to be tested at or near the home s completion. The test measures the CFM50 value of the duct leakage to the exterior only. Leakage to the exterior is the primary concern regarding the energy usage of the home, so the leakage will be the smallest value that can be legitimately used to qualify for ENERGY STR Homes Northwest. There are drawbacks: the home needs to be substantially complete, meaning that any corrections in the duct system will be disruptive and expensive. lso, additional equipment (the blower door) is needed for this test. Example 1 Tools and Equipment: lower Door and Duct Tester Manometer with tubing and static pressure probe Masking tape and paper and/or duct mask to seal registers Setup: Start as in the total leakage test, except the extra door or window should NOT be open to the outdoors in this test. Run an extra hose from the exterior to the area where the duct tester manometer is located (don t attach it yet to the manometer). Set up the blower door in an exterior door. Turn the fan or change the switch to pressurize the house. You do not need to attach the fan pressure hose, the blower door flow will NOT be measured during this test. 14
Duct Systems Duct Leakage to Exterior Example 1. Duct Tester (DT) hooked up at return register. DT is inside pressurized space H 1. Using the blower door, pressurize the interior to +50 Pa WRT outdoors. (Channel ) + 50. 3 Duct Systems Design & Testing Test: 1.Using the blower door, pressurize the interior to +50 Pa WRT outdoors. Duct Leakage to Exterior Example 1. Duct Tester (DT) hooked up at return register. DT is inside pressurized space 2. Pressurize the ducts to 0 Pa WRT interior. (Channel ) 0.0 H 2. With the Duct Tester, pressurize the ducts to 0 Pa WRT interior. The duct pressure WRT interior should start as a negative reading. 15
Duct Systems Duct Leakage to Exterior 3 Duct Systems Design & Testing Example 1. Duct Tester (DT) hooked up at return register. DT is inside pressurized space H 3. Check that the ducts are 50 Pa WRT outdoors. (Channel ) 50.0 3. Connect the outdoor reference hose to the reference tap on the manometer, and check that the ducts are pressurized to + 50Pa WRT outdoors. If they are not, adjust the duct tester and blower door until the ducts are at both 0 Pa WRT the house and at 50 Pa WRT outdoors. Duct Leakage to Exterior Example 1. Duct Tester (DT) hooked up at return register. DT is inside pressurized space 4. Read the fan pressure (Channel ) 122 H 4. Measure Fan Pressure of the Duct Tester. If the fan pressure is less than 30 (if the fan flow reading blinks), turn off the fan and install a smaller low flow ring, so that the fan pressure is higher than 30, and re-take the test. 16
Duct Systems 5. Set the manometer for the correct ring configuration, and read and record the CFM of fan flow. This is the CFM50 leakage of the system. If you cannot get the duct-to-house pressure to 0 (i.e., it stays negative even when the fan is fully on), try using a larger flow ring or open fan. If you still cannot get the duct-to-house pressure to 0 with open fan, reduce the blower door fan speed to bring the house pressure down to a point where this is achievable. Repeat steps 3, 4, and 5 at the reduced pressure, then adjust your results using Table 1 (see page 13). Example 2 Duct Tester is hooked up at ir Handler. Depending on the location of the ir Handler, the Duct Tester may be either inside or outside the pressurized zone of the house (outside in pictured example). Follow the same steps as in Example 1. 3 Duct Systems Design & Testing Note: In this example because the Duct Tester is outside the pressurized zone of the house, it is no longer necessary to run a pressure hose from the reference pressure tap on channel to the outside when determining the duct pressure WRT to outside as it was in Example 1. In any case, if either the house or the ducts can t be pressurized to 50 Pa WRT to outside, pressurize them both to highest same value possible that is a multiple of 5 Pa, and then convert to CFM50 using Table 1 (see page 13). Duct Leakage to Exterior (Example 2) Example 2. Duct Tester (DT) hooked up at air handler. DT is outside pressurized space 1. Using the blower door, pressurize the interior to +50 Pa WRT outdoors. (Channel ) + 50. 17
Duct Systems Duct Leakage to Exterior 3 Duct Systems Design & Testing +50. 2. With the Duct Tester, pressurize the ducts to +50 Pa WRT outdoors. (Channel ) Example 2. Duct Tester (DT) hooked up at air handler. DT is outside pressurized space Duct Leakage to Exterior + 0. 3. With the Duct Tester, verify that the ducts are 0 Pa WRT the house. (Channel ) Example 2. Duct Tester (DT) hooked up at air handler. DT is outside pressurized space 18
Duct Systems Duct Leakage to Exterior +85 4. Read the fan pressure. (Channel ) Example 2. Duct Tester (DT) hooked up at air handler. DT is outside pressurized space 3 Duct Systems Design & Testing Interpreting Results: y pressurizing the house to the same pressure as the ducts, holes between the ducts and the house are assumed to have no pressure difference and therefore make no contribution to the measured CFM50. ll the measured leakage is to the exterior. Generally this will be a more reliable indicator of potential energy savings than a Total Leakage test. The test doesn t give any indication of where to find the holes, just an estimate of the collected hole size to the outside. s CFM50 values get larger, they will tend to be less accurate. In the range of values required for certification, the test should be most accurate. Limitations: The test assumes that the pressures inside the ducts and outside the ducts within the house are always equal during the test. This is not always true and may skew the results. Two story houses with ducts in the second story floor cavity and houses with ducts in other buffer zones that are partially pressurized by the blower door may produce unreliable results. 19
Duct Systems 3 Duct Systems Design & Testing 20
CZ Test 4 Combustion ppliance Zone (CZ) Test 4 CZ Test Requirements ased on the protocol for Combustion ppliance Zone Pressure Testing forced air system operation shall not de-pressurize a combustion appliance zone by more than 3 Pascals. This test is required whenever a primary heating or water heating combustion appliance is present within a building*. Combustion ppliance Zone (CZ) is any zone in the house that contains an atmospherically vented or induced draft combustion appliance used for primary space or water heating (decorative fireplaces or wood stoves, gas cook stoves, or sealed combustion appliance[s] that have an isolated combustion path preventing mixing of room air and combustion air are not included). Combustion ppliance Zones need not be within the heated space. The test measures the magnitude of any air handler-induced pressure effects within the CZ. n optional additional test may also be done with exhaust appliances running. Depressurization of a combustion appliance zone by more than 3 Pascals with reference to outside is considered a potential hazard. In these cases mitigation by adding pressure relief paths, balancing the air handler flow, or other means is recommended. Tools: Micro-manometer, hoses Set Up: Identify the CZ for the home. There may be more than one, in which case the test will need to be conducted for both. The house should be set up for normal heating season operation with all exterior doors and windows closed. *dditional tests may be required for compliance with the Oregon State Tax Credit Program. 21
CZ Test 4 CZ Test Turn off all exhaust devices including clothes dryer, bathroom fans, kitchen fan, central vacuum, and whole house ventilation systems. Open all return and supply registers. Turn off combustion devices so that they will not operate during the test (except furnace if air handler will not operate at high speed without firing). Remove furnace filters. Shut off any outside ventilation air to the duct system if it can normally be shut off during air handler operation. Close manual flue dampers. Measure aseline Pressure: Place one end of the measuring tube outside the house, and attach the other end to the reference tap on the pressure gauge. n extra long hose is very handy for this test. Leave the input port open to read pressure inside the house. ir Handler (H) Induced Combustion ppliance Zone (CZ) De-pressurization Test: H -3Pa 22
CZ Test 1. Record the gauge pressure in Pa. This is the ase Pressure. 2. If there is wind, switch to longer-term average reading. 3. Turn on air handler at the highest speed available; this may need to be cooling mode, or with the furnace running. (To run fan in cooling mode without cooling in cold weather, turn off circuit breaker or disconnect to outdoor unit and activate thermostat for cooling.) CZ Test-ir Handler Effect: Interior Door Setup If the room WRT house is positive (or 0), leave the door closed. 4 CZ Test + 7.0 H + 4. Door set-up. Moving through the home, check the door position for each interior door. Close the door, then measure the pressure of the CZ Test-ir Handler Effect: Interior Door Setup If the room WRT house is negative, open the door. - 2.0 H 23
CZ Test room with reference to the main body of the house. If the pressure is positive or zero, leave the door closed. If the pressure is negative, leave the door open. Note that this allows observation of the effectiveness of zone pressure relief (see ppendix C). ir Handler (H) Induced Combustion ppliance Zone (CZ) De-pressurizationTest 4 CZ Test - 3.5 H + 5. Record the pressure in the CZ with respect to (WRT) outside. This is the air handler induced pressure. 6. Subtract the baseline pressure from this reading, to get the net CZ depressurization. (Example: CZ 5, baseline 2, net is 3. Example 2: CZ +1, baseline 1, net is +2.) 7. If the net change from the baseline is 3 Pa or more negative, there is a potential problem with atmospheric appliances. If the net is 15 Pa or more negative, there is also a potential problem with induced-draft (i.e., power vented ) appliances. 8. If the CZ is in the garage, you may also want to check the pressure in the garage WRT the house. If it is more negative than it is during the baseline condition (all fans off), there is a possibility of garage air being drawn into the home through return leaks. Worst Case Test (Optional) Turn on all the exhaust fans in the house, except for whole-house ventilation fans. Exhaust fans include clothes dryer, bathroom fans, kitchen fan, and central vacuum that exhausts to outside. Repeat Step 4 (interior door set-up) for any rooms that have exhaust fans in them. Record pressure of CZ WRT outside for worst case setup. 24
CZ Test Example: aseline pressure = 1.0 Pa CZ Test = 3.5 Pa Net depressurization effect equals CZ test pressure minus baseline pressure. Net depressurization = 3.5 ( 1.0) = 2.5 Pa Interpreting Results If the net depressurization is 3.0 Pa or more for atmospherically vented appliances, ( 3.0 or more negative), or 15 Pa or more for induced-draft appliances ( 15.0 or more negative), modifications should be made to reduce the de-pressurization. If the supply ducts have been well sealed, the induced depressurization is most probably a result of door closure effects and may be mitigated by undercutting doors, installing transfer grilles or new returns into rooms without returns, or possibly by providing controlled, dampered supplemental make-up combustion air to the CZ. 4 CZ Test 25
CZ Test 4 CZ Test 26
lower Door 5 lower Door Testing 5.1 lower Door ir Leakage Testing When to Test This describes the blower door test protocol for testing the air-leakage of a single family house. Testing in new construction shall occur after everything is roughed-in/installed that will penetrate the building envelope (e.g., plumbing, electrical, HVC, ventilation, combustion appliances, etc.) and the air barrier has been installed. Generally, this is at a minimum after the drywall is hung and taped, and all ductwork, all exterior doors/windows, and attic and crawlspace hatches are installed. 5 lower Door Testing NOTE: The basic setup and operation of a lower Door is an integral part of the Duct Leakage to the Exterior (Chapter 3) test. Equipment Set-up: lower door equipment shall be set-up using the procedure described by the instrument manufacturer. It is assumed that most tests will be performed with a digital pressure gauge. If magnahelic gauges are used, special attention must be paid to ensuring gauges are at room temperature and that gauge hystersis has been reduced or eliminated through proper procedures (described in product literature). When setting up the reference (outside) pressure measurement location and input (inside) location, make sure the end of each hose is not in the air stream of the blower door. Use of a static pressure tap is recommended. 27
lower Door 5 lower Door Testing Tools: lower Door Manometer, hoses Set Up: Close all exterior doors and windows, including pass-through woodbox doors, pet doors, etc.. Open all interior doors (except closets). Seal or fill with water any plumbing drains with p-traps that may be empty. Operable crawl-space vents, where present, are to be left in the open position. Exterior vent openings without backdraft dampers (e.g., that are part of a continuous ventilation system) shall be temporarily sealed for the test. Heat recovery ventilator supply openings shall be sealed. Heat recovery ventilator exhaust openings without backdraft dampers shall not be sealed. ll exhaust fan openings, vent openings, and intake-air vents with backdraft dampers (e.g., dryer vents and kitchen, bathroom, utility room, whole-house, range vents, etc.) shall NOT be sealed. Open dryer exhaust ducts with no dryer installed shall be left unsealed, regardless of whether a backdraft damper is present. Close fireplace or wood stove dampers and doors, but do NOT seal them. Leave any combustion air ducts or louvers to the exterior open. (If a homeowner or builder has sealed them, open them for the test.) Turn off all exhaust devices including: clothes dryer, bath fans, kitchen fans, and central vacuum cleaner. Set thermostat to Off so the HVC system will not come on during testing. Supply and return registers shall NOT be sealed; HVC ducts shall be tested with the envelope. Open all HVC register dampers. Dampers in the outside-air supply duct into the return plenum shall be left as-is. Turn all ventilation controls to Off position. Turn down combustion water heater so it will not fire during the test (i.e., set to pilot and check to confirm pilot is still lit after testing. Relight if necessary.). Set up blower door. Channel, pressure tap, house WRT outdoors. Channel, fan pressure WRT house (depressurization test only. If you wish to pressurize, consult the equipment manufacturer s manual for proper set-up. Danger! Never perform test if any combustion appliance is operating; fires in fireplaces or wood stoves, gas ovens or range tops, etc. 28
lower Door asic lower Door Setup 1. Depressurize interior to 50 Pa With Respect To (WRT) outdoors. (Channel ) 50. H 5 lower Door Testing Test: 1. Measure the pressure in the house with respect to outside before testing is begun to get the baseline offset. If using the newest digital pressure gauges, this correction may be done automatically.) Otherwise, record the baseline offset before proceeding. 2. Using the blower door depressurize the interior to 50 Pa WRT outdoors. 3. Measure fan pressure of the blower door. If the fan pressure is less than 30 (if the fan flow reading blinks), turn off the fan and install a smaller low flow ring, so that the fan pressure is higher than 30, and re-take the test. 4. Set the manometer for the correct ring configuration, and read and record the CFM of fan flow. This is the CFM50 leakage of the system. 5. If the house can t be depressurized to 50 Pa WRT to outside, depressurize it to highest value possible, that is a multiple of 5 Pa, and then convert to CFM50 using Table 1 (see page 13). If wind is a problem, use 5 or 10 second gauge average, and be patient. Error Checking Repeat the test at 25 Pa. It is highly recommended that the technician check the validity of the test. The quick method to do this, assuming that the higher test pressure (around 50 Pa) is very close to twice the lower test pressure (around 25 Pa), is to confirm that the lower test flow is about 0.6 x the higher test flow. That is, if the CFM50 is about 2000 CFM, the 29
lower Door CFM25 is about 1200 CFM. If this relationship does not hold to within 10%, the test should be repeated. When testing is complete reset all thermostats and controls to original settings. 5 lower Door Testing 30
HVC Testing 6 HVC Start Up Testing 6.1 Refrigerant Charge and ir Flow fter installation and start-up, total airflow (CFM) across the heat pump indoor coil shall be measured using a TrueFlow air handler flow meter, the duct tester air flow test, or by temperature rise method using the testing protocols outlined in the testing portion of the chapter. The airflow, along with the temperature difference across the coils and outdoor ambient air temperature at the outdoor coil (for heat pumps), shall be reported to the ENERGY STR Homes Northwest Q Verifier. The air distribution system design and installation shall be such that air flow across the indoor coil is as specified in the heat pump manufacturer s literature, or is between 350 and 400 cubic feet per minute (CFM) per 12000 TU/hr output at RI rating conditions if the manufacturer s literature is not specific. 6 HVC Testing Care must be taken in system design so that the external static pressure acting on the system air handler does not become excessive and affect performance, longevity, and energy usage. The system shall be designed and installed such that external static pressure does not exceed 0.6" w.c. for Permanent Split Capacitor (PSC) motors or 0.8" w.c. for Electrically Commutated Motors (ECM). measurement of external static pressure should be taken at start up to assess potential problems. Refrigerant Charge and Indoor Coil irflow Verification (Heat Pumps) The Participating Installer shall refer to manufacturer s guidelines when charging system and make any needed adjustments for non-standard line set lengths or mismatched coils. Refrigerant charge shall be checked using 31
HVC Testing Proctor Engineering s CheckMe! program, Honeywell s Service ssistant, or other approved methods. 6 HVC Testing Exception: s approved by the SCO, the installer may provide a full documentation of the charge requirements (manufacturer s recommendations, line set size and length) and certification of charge installed to meet this requirement, provided the heat pump has a thermostatic expansion valve (TXV) on the outdoor coil. The installation sheet must be completed and must show the amount of refrigerant added to or subtracted from the system as needed for non standard line set, oversized coil, filter dryer, etc. Temperature split across the indoor coil must also be measured and recorded after 15 minutes of cooling or heating operation. Measurement of system subcooling is highly recommended. irflow across the indoor coil must be measured and recorded. cceptable methods of airflow measurement are the TrueFlow air handler meter, duct tester, or temperature rise method. Results from refrigerant charge tests or charge requirements documentation shall be submitted to the ENERGY STR Homes Northwest Verifier. Temperature Rise ir Flow method for Heat Pumps Only use the temperature rise method if the TrueFlow meter or duct tester method cannot be used. It cannot be used if there is no electric resistance backup heat installed. This is a procedure to calculate the flow of the air handler by measuring the amount of temperature rise across the equipment and combining this with the energy delivered to the air stream by the backup electric resistance heat. Taking several temperature measurements (and averaging) is recommended, but note this method has a tendency to underestimate average supply temperature and can bias the estimate of airflow artificially high. Tools: Digital thermometer mp clamp Cordless drill. Set Up: Turn on the heat pump at the thermostat. Measure and record the static pressure with the system compressor on. This may require that a hole be drilled in the supply plenum. 32
HVC Testing Turn off the heat pump at the thermostat. Turn the thermostat setting down below room temperature. Switch to emergency heat mode. Drill test holes for the supply and return temperature measurements. Holes must be near the air handler, in a well-mixed location with as little turbulence as possible. Do not measure temperatures at supply and return registers. Note: The supply temperature probe must not see the electric resistance heaters in a line of sight: the probe may need to be installed in one of the supply trunks away from the plenum. If necessary, use supply probes in each trunk and average their readings. asic lower Door Setup 1. Depressurize interior to 50 Pa With Respect To (WRT) outdoors. (Channel ) 6 HVC Testing 50. H Test: 1.Turn up the thermostat and let equipment run for 10 minutes, until all the heat stages have come on and readings are stable. Use a 2- channel temperature gauge if possible, and set it to monitor the temperature difference ( ). Once the difference is stable for 2 minutes, record supply and return plenum temperatures. Re-measure these temperatures at least two more times and average all the supply and return measurements. Subtract the return average from the supply average to get the average temperature difference DT. 2.While waiting, measure and record the static pressure in emergency heat mode. If it is different than the pressure in heat pump mode, the fan may be running at a lower speed. The test should be taken at the normal operating speed, or a correction may be made as described in the instructions for the TrueFlow meter. 33
HVC Testing 6 HVC Testing 3. lso while waiting, access the wiring to the heat strip elements at the air handler or circuit breaker box. Do not open any cabinet doors that are part of the air stream to access the wiring. Use safety precautions to avoid electric shock! While waiting for the temperatures to stabilize, monitor the amp reading on the elements to be sure they are not cycling on high limit, or still in the startup staging process. 4. Record element amps and volts. Multiply mps x Volts to get input Watts. Note: if the air handler fan motor is on a different circuit than the strip heaters, measure the amp draw of the fan and add it to the element amps before calculating watts. The house electric meter can also be measured to get input Watts, but all circuit breakers in the house besides the heat pump must be off. 5. Calculate the airflow across the air handler. ir flow = 3.16 x Watts / T. Example: Supply Temperature: 95º F Return Temperature: 70º F T = Supply Return = 95 70 = 25 Strip Heat Element mps = 38 Fan motor mps = 1.2 Total mps = Strip Heat Element + Fan motor = 38 + 1.2 = 39.2 Volts = 240 Watts ir flow = mps x Volts = 39.2 x 240 = 9408 = 3.16 x Watts / T = 3.16 x 9408 / 25 = 1189 CFM 34
Glossary Glossary of Terms CH ir Changes per Hour SP available static pressure CZ Combustion ppliance Zone CFM50 airflow at an induced pressure of 50 Pascals Pascal metric unit of pressure. 1 inch of water column = 249 Pascals SCO State Certification Organization WRT With Reference To. The pressure in the house was 25 Pascals WRT outside. T Temperature difference, for example the difference between supply and return air temperatures. Glossary Table 1: Can t Reach Pressure (CRP) Correction Factors Duct Pressure 10 15 20 25 30 35 40 45 CRP Factor 50 Pa 2.85 2.19 1.81 1.57 1.39 1.26 1.16 1.07 35
Glossary Glossary 36
ppendix ppendix 37
ppendix 38
ppendix ppendix Heat Recovery Ventilation Installation Guidelines The following is a summary of the recommendations for Heat Recovery Ventilation (HRV) or Energy Recovery Ventilation (ERV) installations intended to comply with OP 2, or anywhere an H/ERV is installed in the ENERGY STR Homes Northwest program. While most of the recommendations below are not considered mandatory, they represent good design and installation practice, and should be followed to ensure adequate ventilation air flows. (The only program requirement is shown in bold in item #1 below). Note that these installation guidelines do not apply to other heat recovery equipment, such as ventilating heat pump water heaters. 1. Supply should be provided to the return plenum of central air handling equipment (according to manufacturer s instructions), or to each bedroom and each separate main living area. Exhaust air should be fully ducted. Simplified connection (supply and exhaust both connected to central air handling equipment is not recommended. Guideline: 10 CFM per bedroom or other habitable room, 20 CFM per master bedroom. The requirement for OP 2 is that the system be sized for 0.25 air changes per hour (CH); if it is intended for intermittent operation it may be sized as much as 0.75 CH. This will allow for timer controls designed to operate the unit parttime each hour for an average of 0.25 CH. Total should meet the SHRE 62.2-2003 requirement of 7.5 CFM per occupant + 0.01 CFM per square foot living space. Number of occupants = number of bedrooms +1. 2. Exhaust should be taken from each bathroom area. It is recommended to take exhaust from kitchen (not over range area), laundry, and other moisture-producing areas in the house. 3. Location of outdoor supply and exhaust hoods should meet the guidelines in the HRI Residential Mechanical Ventilation Manual: Protected, and accessible for cleaning; hoods should have rodent screening Intake hoods located away from known contamination sources and above expected snow height (minimum 18" above finished grade); minimum 40" from corner of building Exhaust hoods discharge to outdoors, and minimum 4" above finished grade 39