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“To participate in the EPA’s ENERGY STAR program, the builder and HVAC contractor are required to register, complete training requirements, and maintain credentials which can be accessed through the following link https://www.energystar.gov/index.cfm?fuseaction=opa.showWelcome&p_code=HBUILDER “
The following language is included in our Compliant Resolution Letter which our Raters send to a Client as soon as our Rater is under contract.
If a load calculation method other than Manual J v8 is used, we require our Clients to have this method pre-approved by SWA (prior to HVAC systems being specified and installed).
There are several software packages available that are designed to do these Manual J load calculations, including (but not limited to): Wrightsoft’s Right-Suite
Elite Software’s RHVAC
Adtek Software’s AccuLoad
Examples of commonly used software that do not meet the requirements: HVAC Computer Systems’ HVAC Calc 4.0 (7th edition of ACCA’s Manual J)
Trane’s Trace 700 (commercial sizing tool)
Carrier’s HAP (commercial sizing tool)
Elite Software’s CHVAC (commercial sizing tool)
Thomas & Associates’ HEATLOSS version 3.2 (7th edition of ACCA’s Manual J)
1.2.1 Outdoor design temperatures are equal to the 1% and 99% ACCA Manual J design temperatures for contractor-designated design location What does a 1% or 99% outdoor design conditions mean? This is the
dry-bulb temperature that corresponds to annual cumulative frequency of occurrence. This value represents the value that is exceeded on average by the indicated percentage of the total number of hours in a year (8,760 hrs). For example, the 1.0% outdoor cooling design temperature for Hartford, CT is 88°F. This means that the outdoor conditions only exceed 88°F on average for 87.6 hours per year, or 1.0% of the year.
1.2.1 Outdoor design temperatures are equal to the 1% and 99% ACCA Manual J design temperatures for contractor-designated design location “It should be noted that extreme weather conditions can always occur
that may leave your air conditioning system with temporary limits on delivering full comfort performance. This is much like selecting siding, roofing and window materials to handle very harsh weather conditions, but not extreme weather such as hurricanes and tornadoes.”
1.2.1 Outdoor design temperatures are equal to the 1% and 99% ACCA Manual J design temperatures for contractor-designated design location If contractor uses alternative numbers, need documentation that
justifies their decision (micro-climate, monitored data, etc.). Rater is not required to determine validity of justification.
Through end of 2012, allowed to be within ±5°F of ACCA Manual J design temperature.
1.2.3 Number of Occupants equals number of occupants in rated home. If unknown, this should be (# of bedrooms + 1).
A bedroom is defined by RESNET as a room or space 70 sq. ft. or greater in size, with egress window and closet, used or intended to be used for sleeping. A "den", "library", or "home office" with a closet, egress window, and 70 sq. ft. or greater or other similar rooms shall count as a bedroom, but living rooms and foyers shall not.
If there is a need to accommodate a significant number of temporary occupants (guests) on a regular or sporadic basis, a supplemental cooling system (i.e., mini-split unit) or a variable volume zoning system should be utilized.
For hydronic systems, a schematic displaying room-by-room building loads and the required pipe length needed to provide the Btus should be shown. The specific type of heat emitters used in the design should be specified in the documentation.
For unducted systems, a schematic is still needed that identifies where systems will be located and which rooms will be serviced by each unit.
Often there are letters that can vary so AHRI uses ( ) or * to cover multiple options under the same rating.
Put in the least amount information to start with (manufacturer, 3-5 letters/numbers of outdoor unit and furnace, and first letter/number of indoor coil).
Take a look at what pops up and then revise as needed. If nothing pops up, remove some more letters until something pops up.
1.2.11 Using reported liquid line or suction line pressure, corresponding temperature matches reported condenser or evaporator saturation temperature (+/- 3 degrees)
Did the HVAC contractor read the Pressure/Temperature chart correctly?
1.2.12 Calculated subcooling or superheat value equals reported target subcooling or superheat temperature
You should not be drilling into the ductwork to be making these measurements. Simply use the holes that the contractor used when taking their measurements… you are just verifying test results.
Depending on return side hole, may need to remove filter during this test.
2.3 Flexible ducts in unconditioned space not installed in cavities smaller than outer duct diameter; in conditioned space not installed in cavities smaller than inner duct diameter
2.4 Flexible ducts supported at intervals as recommended by mfr. but at a distance < 5 ft.
2.5 Building cavities not used as supply or return ducts unless they meet items 3.2, 3.3, 4.1, and 4.2 of this checklist. [Insulated and Sealed]
2.6 HVAC ducts, cavities used as ducts, and combustion inlets and outlets may pass perpendicularly through exterior walls but shall not be run within exterior walls unless at least R-6 continuous insulation is provided on exterior side of the cavity, along with an interior and exterior air barrier where required by the Thermal Enclosure System Rater Checklist.
2.8 Bedrooms pressure-balanced using any combination of transfer grills, jump ducts, dedicated return ducts, and/or undercut doors to either:
provide 1 sq. in. of free area opening per 1 CFM of supply air, as reported on the contractor-provided balancing report; or
achieve a Rater-measured pressure differential < 3 Pa (0.012 in. w.c.) with respect to the main body of the house when bedroom doors are closed and the air handler is operating.
Needs to be testing at project completion as all components (air handler and register grilles) need to be installed.
Just because ducts are located in conditioned space, don’t slack on duct sealing. We are finding homes are having a tough time meeting total even when leakage to outside is basically zero.
If supply-only connected into AHU, need have access point or damper to seal off outdoor air supply duct.
7.1 All ventilation air inlets located ≥ 10 ft of from known contamination sources (stack, vent, exhaust hood, or vehicle exhaust). Exception: ventilation air inlets in the wall ≥ 3 ft. from dryer
exhausts and contamination sources exiting through the roof.
7.2 Ventilation air inlets ≥ 4 ft. above grade or roof deck in Climate Zones 4-8 and not obstructed at time of inspection. Pay close attention, if ventilation system (supply-only or
7.3 Ventilation air inlets provided with rodent / insect screen with ≤ 0.5 inch mesh.
7.4 Ventilation air comes directly from outdoors and not from adjacent dwelling units, garages, crawlspaces, or attics.
If exhaust-only ventilation is used in attached housing, likely can’t avoid this…but make sure demising wall is sealed as well as possible to compartmentalize (this improves the fire assembly, noise attenuation, and odor transmission)
Most bath fans deliver their rated flow at pressure drops of 0.1 inches of water gauge (wg). As a reference, this is roughly the pressure drop created by 50 CFM of
flow through a grille, 5 ft of 3-inch flex duct, and a wall cap for the fan...that’s it!
It's best to use the rated flow at 0.25” wg. to meet the required flow rate, since this is more likely to be the typical static pressure when fans are installed. A typical fan rated at 50 cfm @ 0.1” static pressure will operate closer to
23-31 cfm at 0.25” static pressure. An 80 cfm fan at 0.1” will operate at roughly 48-57 cfm at 0.25” static pressure.
Homeowner – “We have recently been noticing evidence of molding around the bathroom window, resulting from very high humidity level throughout the house (but especially the master bath). This is really a big concern to us because we have been living in the house for just under 2 months, and to have evidence of molding and mustiness reappear is a big issue to us.”
Here is a perfect example why performance testing is essential to quality control/assurance.
Three of the bath fans were restricted in one fashion or another causing blow back into the conditioned space. It is common to see the exhaust fan backdraft damper screwed shut at the connection of the fan housing to the ductwork. Though the exhaust fans were operating, they were not extracting the excess moisture.
11.3 Filter located and installed so as to facilitate access and regular service by the owner.
If the filter is located in the attic, must have a drop-down stairs (no attic hatches) and a permanently installed walkway/platform to get to the filter.
11.4 Filter access panel includes gasket or comparable sealing mechanism and fits snugly against the exposed edge of filter when closed to prevent bypass.
Aluminum tape is not acceptable, as the homeowner needs to be able to change filter and re-secure the filter cover.
Designing Forced-Air HVAC Systems: http://www.carb-swa.com/articles/guidelines/Forced%20Air%20HVAC%20Guide%20updated%208_31_10.pdf Why Right-Size? Science versus Practicality: http://www.carb-swa.com/articles/guidelines/Why%20to%20Rightsize%20Guide.pdf Guidelines for Complying with BPI’s Technical Standards for the Air Conditioning and Heat Pump Professional: http://www.carb-swa.com/articles/guidelines/Guidelines%20for%20Complying%20with%20BPI%20AC%20Tech%20Standards_10052010.pdf Ventilating Your Home: http://www.carb-swa.com/articles/guidelines/Ventilation%20Guide%20updated%208_5_09.pdf HVAC System Quality Installation Rater Checklist Guidebook Slide Deck: http://www.energystar.gov/index.cfm?c=bldrs_lenders_raters.nh_v2_v3_training_resources#checklist