ASHRAE Journal - July 2023 - 45

TECHNICAL FEATURE
necessary in the 90.1 Mechanical Effi ciency
Tables that appear in Section 6.8.1.
Single-phase HVAC products with a capacity
less than 65,000 Btu/h (5.4 tons, or
19 kW) are controlled by the National Energy
Conservation Policy Act, which preempts
local building code effi ciency requirements.
These are included in 90.1 Informative
Appendix F for reference. Commercial products
as defi ned in the Energy Policy Act are
also preemptive. The requirements for such
products may be established by ASHRAE
Standard 90.1 and then approved by the DOE
or established directly by the DOE. Products
subject to federal preemption are listed in
Tables 1 and 2.
Effi ciency tables are included in Section 6
for HVAC&R products, Section 7 for Service
Water Heating, and Informative Appendix
F for DOE-defi ned and controlled products.
Equipment effi ciency requirements are
unique in that many are federally controlled
and preempt effi ciency levels that may
be listed in local building code effi ciency
requirements. ASHRAE Standard 90.1 standards
are updated and released every 3 years
and then adopted by states, cities, and local
building codes-but this can take anywhere
from 1 to 8 years. Once the federally approved effi ciencies
go into effect, manufacturers can no longer produce
the equipment to the older effi ciency levels. Standard
90.1 users should understand how this can impact product
specifi cation during the job planning phase, even if
local building codes have not been updated accordingly.
However, with the exception of <65,000 Btu/h (5.4 ton,
or 19 kW) single-phase air conditioners, equipment that
was already built prior to the effi ciency updates now in
effect can still be installed. The products that fall into
this category are listed in Tables 1 and 2.
In terms of specifi c changes, the effi ciency requirements
for <65,000 Btu/h (5.4 ton, or 19 kW) split systems
and packaged air conditioners and heat pumps have
been adjusted in Standard 90.1-2022. Both the metric
and the required effi ciency has been increased, effective
January 1, 2023, except for three-phase products where
the equipment effi ciency is increased effective January
1, 2025. The metrics changed from SEER to SEER2 for the
TABLE 1 DOE Preemptive Residential Products.
Single-phase residential split systems <65K
Single-phase residential split system HPs <65K
Single packaged air conditioners
Small duct high velocity
Space constrained air conditioners
Space constrained heat pumps
Gas-fi red storage water heaters <100 gal
Oil-fi red storage water heaters <50 gal
Electric storage water heaters <55 gal
Tabletop water heaters
Instantaneous gas-fi red water heaters <50K
TABLE 2 DOE Preemptive Commercial Products.
3-phase commercial split systems <760K
3-phase commercial split system HPs <760K
Packaged air conditioners <760K
HP packaged air conditioners <760K
Commercial split system <760K
HP commercial split systems <760K
3-phase space constrained air conditioners
3-phase space constrained heat pumps
PTAC
PTHPs
SPVAC
SPVHP
Instantaneous electric water heaters <2 gal
Grid enabled water heaters
Pool heaters
Room air conditioners
Residential furnaces <225K
Electric furnaces <225K
Gas-fi red hot-water boilers
Gas-fi red steam boilers
Electric hot-water boilers
Electric steam boilers
Large-diameter ceiling fans
Commercial electric furnaces <225K
Warm air gas duct furnace
Warm air gas and oil unit heaters
Hot water gas and oil boilers
Steam gas and oil boilers
Commercial fans
VRF
Computer room air conditioners
Water source heat pumps
Commercial refrigerators and freezers
Dedicated outdoor air units
Commercial electric storage water heaters
annualized cooling metric, EER to EER2 for the full load
cooling metric, and HSPF to HSPF2 for heat pumps. With
the change in metrics, the stringency increased about
8% for cooling and 11% for heating. In Standard 90.12022,
these changes are documented in Table 6.8.1-1 for
cooling equipment, Table 6.8.1-2 for heat pumps, and
in Table F1 (Appendix F) for federally defi ned and controlled
products.
For commercial rooftops and split systems as defi ned
in Tables 6.8.1-1 and 6.8.1-2, the rating metric has
changed from IPLV to IEER according to a 2010 AHRI
test procedure that resulted in better representation of
annualized building performance. In 2018, as part of a
negotiated ruling, the DOE switched the primary preemptive
regulatory metric from the full load EER to IEER
for air cooled products and adopted Standard 90.1 levels
effective January 1, 2018. The rulemaking also increased
IEER effi ciency levels by an additional 14%; those values
went into effect on January 1, 2023.
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