ES-i

EXECUTIVE SUMMARY

TABLE OF CONTENTS

ES.1 Introduction..........................................................................................................................1

ES.2 Summary of Rulemaking Process........................................................................................1

ES.3 Preliminary Activities..........................................................................................................1

ES.4 Key Analyses and results.....................................................................................................3

ES.4.1 Market and Technology Assessment ...................................................................................3

ES.4.2 Screening Analysis...............................................................................................................4

ES.4.3 Engineering Analysis...........................................................................................................4

ES.4.3.1 Product Classes Analyzed................................................................................. 4

ES.4.3.2 Efficiency Levels Defined ................................................................................ 5

ES.4.3.3 Manufacturer Costs and Selling Prices............................................................. 7

ES.4.4 Markups to Determine Product Price...................................................................................8

ES.4.5 Energy Use Characterization ...............................................................................................9

ES.4.6 Life-Cycle Cost and Payback Period Analysis..................................................................11

ES.4.7 Shipments Analysis............................................................................................................14

ES.4.8 National Impact Analysis...................................................................................................15

ES.4.8.1 Efficiency Trend ............................................................................................. 15

ES.4.8.2 National Energy Savings................................................................................. 16

ES.4.8.3 Net Present Value ........................................................................................... 17

ES.4.9 Preliminary Manufacturer Impact Analysis.......................................................................18

ES.5 Issues on which the Department Seeks Public Comment..................................................19

ES.5.1 Portable AC Product Classes.............................................................................................19

ES.5.2 Efficiency Levels...............................................................................................................19

ES.5.3 Design Options and Cost Estimates...................................................................................19

ES.5.4 Lifetime of Portable ACs...................................................................................................19

ES.5.5 Energy Use Determination.................................................................................................19

ES.5.6 Operating Hours for a Standards Case...............................................................................20

ES.5.7 Commercial Use of Portable ACs......................................................................................20

ES.5.8 Historical Shipments of Portable ACs...............................................................................20
ES-ii

LIST OF TABLES

Table ES.4.3.1 Portable AC Efficiency Level Characteristics ........................................................5

Table ES.4.3.2 Portable AC Efficiency Level Equation Coefficients.............................................6

Table ES.4.3.3 Incremental Portable AC Manufacturer Production Costs......................................8

Table ES.4.4.1 Markups for Determining Portable AC Product Price ............................................8

Table ES.4.5.1 Portable ACs: Average Annual Energy Use by Efficiency Level ........................11

Table ES.4.6.1 Summary of LCC and PBP Results by Efficiency Level for Portable ACs 

at Residential Sites.................................................................................................13

Table ES.4.6.2 Summary of Life-Cycle Costs Relative to the Base-Case Efficiency 

Distribution for Portable ACs at Residential Sites ................................................13

Table ES.4.6.3 Summary of LCC and PBP Results by Efficiency Level for Portable ACs 

at Commercial Sites...............................................................................................14

Table ES.4.6.4 Summary of Life-Cycle Costs and Savings Relative to the Base-Case 

Efficiency Distribution for Portable ACs at Commercial Sites.............................14

Table ES.4.8.1 Portable ACs: Distributions of Base- and Standards-Case Efficiencies in 

2019 for Residential and Commercial Sectors.......................................................16

Table ES.4.8.2 Cumulative Primary National Energy Savings .....................................................17

Table ES.4.8.3 National Energy Savings for Full-Fuel-Cycle.......................................................17

Table ES.4.8.4 Cumulative NPV Results Based on 3-Percent and 7-Percent Discount 

Rates.......................................................................................................................18

LIST OF FIGURES

Figure ES.4.3.1 Efficiency Level Curves by Cooling Capacity ......................................................7

Figure ES.4.7.1 Portable ACs Historical Base-Case Shipments and Projection ...........................15
ES-1

EXECUTIVE SUMMARY

ES.1 Introduction

This preliminary technical support document (TSD) describes in detail the approaches to 

and results of preliminary activities that the U.S. Department of Energy (DOE) performed in 

investigating potential energy conservation standards for portable air conditioners (ACs). This 

executive summary summarizes DOE’s preliminary activities and results. Additionally, this 

executive summary delineates issues identified during the analyses about which DOE seeks 

comments from interested parties. Those issues are highlighted in the public meeting 

presentation and are discussed further in chapter 2 of the preliminary TSD.

ES.2 Summary of Rulemaking Process

Section 6295(o)(2)(A) of the Energy Policy and Conservation Act (EPCA), Pub. L. 94-

163, 42 U.S.C. 6291 et seq. requires DOE to establish energy conservation standards that achieve 

the maximum improvement in energy efficiency that is technologically feasible and

economically justified. DOE establishes those standards during rulemakings for energyconsuming consumer products and commercial and industrial equipment. For each rulemaking, 

DOE typically first develops a framework document that describes the approaches and methods 

DOE will use in evaluating the need for new or amended standards. For this rulemaking, DOE 

began the rulemaking process by publishing a notice of proposed determination (NOPD) in the 

Federal Register on July 5, 2013 (hereinafter the “July 2013 NOPD”). 78 FR 40403. After the 

framework stage, or in this case the NOPD, DOE then presents the initial analytical results in a 

preliminary TSD such as this one. DOE publishes in the Federal Register a notice that 

announces the date and place of a public meeting, as well as the availability of the preliminary 

TSD and presentation materials that interested parties may review before the meeting. The notice 

also highlights the major analyses DOE performed in the preliminary stage of the rulemaking. 

ES.3 Preliminary Activities

There are currently no DOE test procedures or energy conservation standards for portable 

ACs. In the July 2013 NOPD, DOE outlined its tentative determination that portable ACs fulfill 

the criteria for being classified as a covered product pursuant to 42 U.S.C. 6292(b)(1). 78 FR 

40403, 40404 (Jul. 5, 2013). DOE may classify a consumer product as a covered product if (1) 

classifying products of such type as covered products is necessary and appropriate to carry out 

the purposes of EPCA; and (2) the average annual per-household energy use by products of such 

type is likely to exceed 100 kilowatt-hours (kWh) (or its British thermal unit (Btu) equivalent) 

per year. 42 U.S.C. 6292(b)(1). DOE estimated in the July 2013 NOPD that 973.7 thousand units 

were shipped in North America in 2012, with a projected growth to 1743.7 thousand units by 
ES-2

2018, representing nearly 80-percent growth in 6 years.a Comments from interested parties in 

response to the July 2013 NOPD were generally supportive of including portable ACs as a 

covered product under EPCA.

In the July 2013 NOPD, DOE proposed a definition for portable ACs to be added in the 

Code of Federal Regulations to clarify coverage of any potential test procedure or energy 

conservation standards for these products. DOE proposed defining a portable AC as “a consumer

product, other than a ‘packaged terminal air conditioner,’ which is powered by a single phase 

electric current and which is an encased assembly designed as a portable unit that may rest on the 

floor or other elevated surface for the purpose of providing delivery of conditioned air to an 

enclosed space. It includes a prime source of refrigeration and may include a means for 

ventilating and heating.” DOE also noted that this proposed definition is mutually exclusive to 

the definition for a room AC, which is “designed as a unit for mounting in a window or through 

the wall.” 79 FR 40403, 40404 (Jul. 5, 2013).

Because portable ACs are not currently covered under EPCA, there are no DOE test 

procedures for these products. In response to the July 2013 NOPD, interested parties commented 

on appropriate test procedures for portable ACs, and on technical issues DOE should address in 

any potential DOE test procedures for these products. Based on this feedback, DOE conducted 

initial investigative testing. On May 9, 2014, DOE published a notice of data availability 

(hereinafter the “May 2014 NODA”) to present the results of the initial testing and to request 

feedback on potential testing options. 79 FR 26639. Based on feedback received in response to 

the May 2014 NODA and further investigative testing, DOE proposed a test procedure for 

portable ACs in a notice of proposed rulemaking (NOPR) issued on February 12, 2015 

(hereinafter the “February 2015 Test Procedure NOPR”).

b

In the February 2015 Test Procedure 

NOPR, DOE also proposed an updated portable AC definition. The newly proposed definition 

would provide additional clarification regarding the scope of products that would be considered 

portable ACs, and would align with the definitions for dehumidifiers and room ACs. The newly 

proposed definition for “portable air conditioner” is as follows:

An encased assembly, other than a “packaged terminal air conditioner,” “room air 

conditioner,” or “dehumidifier,” designed as a portable unit for delivering cooled, conditioned air 

to an enclosed space, that is powered by single-phase electric current, which may rest on the 

floor or other elevated surface. It includes a source of refrigeration and may include additional

means for air circulation and heating.

DOE will consider comments and information received from interested parties on the 

revised portable AC definition proposed in the February 2015 Test Procedure NOPR, and 

expects to establish the final definition in a future determination of coverage.

 

a Transparency Media Research, Air Conditioning Systems Market - Global Scenario, Trends, Industry Analysis, 

Size, Share and Forecast, 2012 – 2018, January 2013.

b The test procedure is available at: 

http://www1.eere.energy.gov/buildings/appliance_standards/product.aspx/productid/79. 
ES-3

Chapter 1 of this preliminary TSD summarizes DOE’s appliance standards program and 

how it applies to this rulemaking, and then outlines the structure of this document. Chapter 2 of 

the preliminary TSD summarizes the analytical framework for this rulemaking, the comments 

received in response to the July 2013 NOPD, and DOE’s responses to those comments. 

Subsequent chapters describe in detail the preliminary analyses performed for this stage of the 

rulemaking. Descriptions include inputs, sources, methods, and results. 

ES.4 Key Analyses and results 

The following sections summarize the key analyses DOE performed and the results 

obtained in developing this preliminary TSD. 

ES.4.1 Market and Technology Assessment 

When initiating an analysis of potential energy conservation standards for appliances, 

DOE obtains information on the present and past industry structure and market characteristics for 

the products concerned. DOE assesses industries and products both quantitatively and 

qualitatively, based on publicly available information. 

For this rulemaking, DOE addressed (1) manufacturer market share and characteristics, 

(2) existing regulatory and non-regulatory initiatives for improving product efficiency, and (3) 

trends in product characteristics and retail markets. These data and resource material were used 

throughout the analysis.

DOE reviewed available public literature and interviewed manufacturers to develop an 

overall understanding of the portable AC industry in the United States. In particular, DOE sought

information on: (1) manufacturers and their market share; (2) product information; and (3) 

industry trends. Chapter 3 of the preliminary TSD describes the market analysis and resulting 

information.

DOE typically uses information about existing and past technology options and working 

prototype designs to determine which technologies and combinations of technologies 

manufacturers use to attain higher performance levels. In consultation with interested parties, 

DOE develops a list of technologies to be considered. 

DOE developed a list of technologies for portable ACs from trade publications, technical 

papers, manufacturer literature, and through consultation with manufacturers. Because existing 

products contain many technologies for improving product efficiency, product literature and 

direct examination provided additional information. 
ES-4

ES.4.2 Screening Analysis

The screening analysis (chapter 4 of the preliminary TSD) examines whether 

technologies identified in the technology assessment (1) are technologically feasible; (2) are 

practicable to manufacture, install, and service; (3) have an adverse impact on product utility or 

availability; and/or (4) have adverse impacts on health and safety. DOE conducted this screening 

analysis in consultation with interested parties. In the subsequent engineering analysis, DOE 

further examined the technology options that it did not remove from consideration in the 

screening analysis.

ES.4.3 Engineering Analysis

The engineering analysis (chapter 5 of the preliminary TSD) establishes the relationship 

between the costs of manufacturing portable ACs and their efficiencies. These relationships 

serve as the basis for calculating costs and benefits of modified product designs for consumers, 

manufacturers, and the nation. Chapter 5 describes the product classes DOE analyzed, the 

representative baseline units, the efficiency levels DOE considered, the methodology DOE used 

to develop the manufacturing production cost model, and the cost-efficiency results.

ES.4.3.1 Product Classes Analyzed

Because portable air conditioners are not currently covered under EPCA, there are no 

existing product classes for these products. 

For this preliminary analysis, DOE considered whether it should separate portable ACs 

into separate product classes based on two characteristics: duct configuration and cooling 

capacity (hereinafter referred to as “capacity”). Portable ACs are typically available with two 

types of duct configurations that affect product performance. Single-duct units draw all of the 

condenser inlet air directly from the conditioned space without the means of a duct, and 

discharge the hot condenser outlet air to the unconditioned space through a duct. Dual-duct units 

draw some or all of the condenser inlet air from the unconditioned space through a duct, and may 

draw additional condenser inlet air directly from the conditioned space. The condenser outlet air 

is discharged to the unconditioned space by means of a separate duct. Portable ACs of a third 

type of duct configuration, spot coolers, draw and discharge all evaporator and condenser air to 

and from the conditioned space, and typically direct the evaporator outlet air to a localized space 

within the conditioned space. The February 2015 Test Procedure NOPR does not include 

measures of spot coolers performance, so DOE conducted this preliminary analysis only on 

single-duct and dual-duct portable ACs.

Single-duct units typically create more net negative pressure within the conditioned space 

than dual-duct units, leading to more infiltration airflow from outside the conditioned space. This 

typically leads to lower single-duct unit efficiencies than for comparable dual-duct units when 

measured according to the method proposed in the February 2015 Test Procedure NOPR. 
ES-5

Although duct configuration impacts unit performance, DOE determined that duct configuration 

does not require separate product classes because there is no unique consumer utility associated 

with either configuration.

Additionally, portable AC efficiencies are a function of product capacity. Higher-capacity 

units typically achieve a higher cooling energy efficiency ratio (EERcm) than lower-capacity 

units when measured according to the method proposed in the February 2015 Test Procedure 

NOPR. DOE observed from its test data that this relationship between EERcm and capacity is 

consistent across the range of measured capacities for products that implement the same 

technologies. DOE did not identify any inherent differences in efficiency for different ranges of 

capacity that would produce a different efficiency-capacity relationship. Therefore, DOE is not 

proposing separate portable AC product classes based on capacity. Instead, DOE is proposing 

equations to relate EERcm to capacity.

Accordingly, DOE did not separate portable ACs into any additional product classes for

this preliminary analysis.

ES.4.3.2 Efficiency Levels Defined

DOE based its preliminary analysis for portable ACs on EERcm as proposed in the 

February 2015 Test Procedure NOPR. Although this metric is an intermediate step in 

determining the combined energy efficiency ratio (CEER), DOE focused its preliminary analysis 

on efficiency improvements in the cooling mode operation because this is the primary function 

of a portable AC. In the NOPR phase of this rulemaking, DOE expects to base the analysis on 

CEER to account for portable AC operation in additional modes, including off-cycle, inactive or 

off mode, and heating mode, when available.

As discussed in section ES.4.3.1, DOE developed equations relating EERcm to cooling 

capacity. According to the procedure proposed in the February 2015 Test Procedure NOPR, 

DOE observed that measured EERcm and capacity are dependent on a unit’s duct configuration 

and airflow optimization to minimize infiltration air (i.e., the volume of condenser inlet air 

drawn from either the conditioned space or from the unconditioned space through the condenser 

inlet duct, if available). DOE determined that appropriate efficiency levels for the analysis would 

first be based on incremental changes to the duct configuration and airflow pattern, with a 

maximum EERcm efficiency level that accounts for efficiency gains associated with a dual-duct 

configuration with an optimal airflow pattern and additional design options. Table ES.4.3.1

below describes the incremental changes associated with each analyzed efficiency level.

Table ES.4.3.1 Portable AC Efficiency Level Characteristics

Efficiency 

Level

Product Characteristics

Baseline Single-duct unit
ES-6

EL1 Dual-duct unit with 50 percent of condenser inlet air drawn from the 

conditioned space (i.e., 50 percent infiltration air)

EL2 Dual-duct unit with 25 percent of condenser inlet air drawn from the 

conditioned space (i.e., 25 percent infiltration air)

EL3 Dual-duct unit with condenser inlet air drawn entirely from unconditioned 

space via condenser inlet duct (i.e., no infiltration air)

EL4 EL3 unit with improved compressor efficiency, heat exchangers, blower 

efficiencies, and low-standby-power controls.

DOE relied on its investigative testing and modeled data to determine product EERcm and 

cooling capacity at each of the efficiency levels. These data resulted in a range of product 

efficiencies for each efficiency level depending on the individual product capacities. DOE 

evaluated the relationships between cooling capacity and EERcm at each efficiency level 

configuration, and developed the following equation to describe the representative EERcm for a 

given capacity at each efficiency level:

EERcm =

Cooling Capacity

(A × Cooling Capacity + B)

Table ES.4.3.2 below provides the coefficients A and B for each analyzed efficiency 

level which would be used to determine EERcm in Btu per watt-hour (Btu/Wh), and Figure 

ES.4.3.1 plots each efficiency level curve for cooling capacities from 0 to 10,000 Btu per hour 

(Btu/h).

Table ES.4.3.2 Portable AC Efficiency Level Equation Coefficients

Efficiency Level A Coefficient

(Wh/Btu)

B Coefficient

(W)

Baseline 0.113 855.5

EL1 0.1201 685.4

EL2 0.1222 566.3

EL3 0.1256 426.9

EL4 0.1205 355.1
ES-7

Figure ES.4.3.1 Efficiency Level Curves by Cooling Capacity

Chapter 5 of this preliminary TSD includes additional details on how DOE developed the 

efficiency levels for its analysis. 

ES.4.3.3 Manufacturer Costs and Selling Prices

DOE used a hybrid approach of the design-option and reverse-engineering approaches for 

its engineering analysis. This analysis consists of disassembling representative units, analyzing 

the materials and manufacturing processes, analyzing the design approaches manufacturers use, 

and developing a spreadsheet model to ascribe costs to the various designs. DOE also obtained 

input from interested parties on the manufacturing cost model inputs. Chapter 5 of the 

preliminary TSD includes information on the inputs used to determine the manufacturer

production cost (MPC), including material, labor, and overhead prices. DOE then considered the 

design options manufacturers would likely use to achieve higher product efficiencies. DOE 

considered the efficiency level changes described in Table ES.4.3.1 in estimating the incremental 

MPC at each efficiency level. Chapter 5 also includes information on the various components 

and features incorporated into designs for portable ACs, as well as certain design options that 

were retained in the screening analysis but were not considered in the engineering analysis due to 

negligible energy savings potential or inability to be measured according to the test procedure 

proposed in the February 2015 Test Procedure NOPR.

The output of DOE’s engineering analysis is a cost-efficiency curve that relates 

incremental MPC to efficiency for portable ACs. The incremental MPC represents the average 

increase in MPC required to improve a baseline-efficiency product to each of the considered 
ES-8

efficiency levels for each of the products in DOE’s teardown sample. For efficiency levels 1 

through 3, the design changes DOE considered increase product capacity with relatively constant 

energy consumption. Accordingly, the average MPCs for these efficiency levels correspond to 

increases in both EERcm and cooling capacity. Table ES.4.3.3 presents the results of the 

engineering analysis for portable ACs.

Table ES.4.3.3 Incremental Portable AC Manufacturer Production Costs 

Efficiency Level Incremental MPC

(2013$)

EL1 $ 4.09

EL2 $ 4.67

EL3 $ 5.26

EL4 $ 47.76

ES.4.4 Markups to Determine Product Price

In chapter 6 of this preliminary TSD, DOE calculates the markups to manufacturer 

selling prices that occur throughout the distribution channels for portable ACs, converting the 

estimated manufacturer costs derived from the engineering analysis to consumer prices. In 

calculating markups, DOE identified the distribution channels for portable ACs and the markup 

associated with each step in the channels. The manufacturer markup converts MPC to 

manufacturer selling price (MSP). DOE developed an average manufacturer markup by 

examining the annual Securities and Exchange Commission (SEC) 10-K reports filed by publicly 

traded manufacturers primarily engaged in appliance manufacturing. DOE estimated the 

markups taken by retailers and also included sales taxes. DOE developed separate retailer 

markups for baseline products (baseline markups) and for the incremental cost attributable to 

more expensive, more efficient products (incremental markups). Table ES.4.4.1 summarizes the 

markups DOE developed for the prices consumers pay for portable ACs.

Table ES.4.4.1 Markups for Determining Portable AC Product Price

Distribution Step

Markup

Baseline Incremental

Manufacturer 1.42

Retailer 1.36 1.11

Sales Tax 1.07

Overall 2.07 1.69
ES-9

ES.4.5 Energy Use Characterization

DOE assessed the energy savings potential of higher-efficiency portable ACs in order to 

develop energy savings values to be used in the life-cycle cost and subsequent analyses. The goal 

of the energy use characterization is to generate a range of energy use values that reflect realworld portable AC use in American homes and businesses. By incorporating data on how

portable AC products actually are used by U.S. consumers, DOE can estimate the energy that 

would be consumed (or potentially saved) by products having various efficiency levels. As part 

of the energy use analysis, certain engineering assumptions and data are required, including how 

often the product is operated and in which mode of operation (cooling, fan-only, or standby/off), 

the size of the area to be cooled, installation conditions, and climate conditions. Because DOE 

found few real-world data to approximate portable AC energy use, DOE had to make various 

assumptions to perform the energy use analysis. 

Critical to DOE’s energy use analysis was room AC data from the Energy Information 

Administration’s (EIA’s) 2009 Residential Energy Consumption Survey (RECS 2009) and 2003 

Commercial Buildings Energy Survey (CBECS 2003), the most recent surveys available at the 

time of DOE’s analysis. Both surveys collect nationally representative information related to 

consumers’ appliance use and energy consumption, including the use of window- or wallmounted room ACs. The two surveys collect data on annual energy costs for cooling, along with 

climate-related characteristics. DOE’s assumptions include the following considerations.

 Ownership of a window- or wall-mounted room AC used in a RECS 2009 household 

or CBECS 2003 enterprise could be used to approximate the ownership of a portable 

AC.

 The portable AC was installed according to manufacturer instructions (for example, a 

dual-duct portable AC would have both ducts installed and properly insulated).

 The number of operating hours spent in cooling mode for a window- or wall-mounted 

room AC used in a RECS household or CBECS enterprise could be used to 

approximate the hours a portable AC spends in cooling mode.

 The upper limit of total hours of portable AC operation in either cooling or fan-only 

mode were estimated assuming that a portable AC would be operated only in months 

having 5 or more cooling-degree days that exceed 65 degrees Fahrenheit (°F).

 For rooms measuring less than 250 square feet, the portable AC setpoint can be 

reached (the cooling load is constant) and operating hours would decrease with a 

higher-capacity portable AC.

 For rooms measuring 250 square feet or more, the cooling load could not be met by 

increasing the capacity of the portable AC and, therefore, cooling operation would 

continue until the user turned off the unit. The operating hours spent in cooling mode 

would remain constant for any portable AC operating at any efficiency level. 

 The average capacity at each efficiency level reflects the full range of capacities at 

that efficiency level.
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The energy use analysis requires DOE to establish a range of total annual operating hours 

as well as hours for each mode of operation (cooling or fan-only). DOE utilized RECS 2009 and 

CBECS 2003 data to establish the upper limit of portable AC annual operating hours for both 

modes of operation. To estimate annual portable AC use and energy consumption, DOE began 

by assigning each RECS household and CBECS commercial enterprise that uses a room AC to 

one of the 321 weather stations operated by the National Oceanic and Atmospheric 

Administration (NOAA). DOE identified which weather station best matched the heating and 

cooling degree-days in the RECS 2009 data set or the CBECS 2003 data set. The climate data 

obtained from NOAA’s National Climatic Data Center helped DOE determine the maximum 

amount of time the portable AC would be operated annually and apportion the annual electricity 

use for portable ACs in various geographic areas among the months of the year. DOE assumed a

portable AC would be operated in cooling mode only during months having 5 or more coolingdegree days that exceed 65 °F.

DOE was able to use RECS 2009 and CBECS 2003 room AC data to estimate the range 

of annual operating hours a portable AC spends in cooling mode based on the method used in 

DOE’s 2011 final energy conservation standards rulemaking for room ACs. DOE assumed the 

operating hours calculated for households and businesses having a room AC represent operating 

hours spent in cooling mode for a baseline portable AC unit. The energy use of a portable AC

motor during cooling mode was calculated using the method for determining rated capacity and 

efficiency stipulated in the February 2015 Test Procedure NOPR. The distribution of operating 

hours spent in fan-only mode is based on a preliminary analysis of field-metered data (Burke et 

al.c), in which DOE assumed that fan-only time was proportional to cooling-mode time. DOE 

estimated that time spent in fan-only mode was about 30 percent of the time spent in cooling 

mode.

An additional factor in DOE’s energy use analysis is the square footage of the room the

portable AC attempts to cool. In cases where the baseline portable AC adequately meets the 

cooling load of a room, a higher-capacity unit will reduce the hours of operation in cooling 

mode. If the baseline unit cannot handle the cooling load, however, field metering data indicate 

the compressor will remain running until a user turns the unit off. (Burke, et al.). A study of

portable AC performance conducted by Consumer Reportsdfound that portable ACs tested in a 

250-square-foot room labored to provide adequate cooling. Based on those observations, DOE 

assumed households using a higher-efficiency (and thus higher-capacity) portable AC in a room 

measuring less than 250 square feet would experience a reduction in hours of operation in 

cooling mode, assuming a fixed load. In areas that meet or exceed 250 square feet the hours 

 

c T. Burke, et al., Using Field-Metered Data to Quantify Annual Energy Use of Portable Air Conditioners, Lawrence 

Berkeley National Laboratory, Report No. LBNL-6868E (December 2014). Available at: 

www.osti.gov/scitech/servlets/purl/1166989.

d

June 12, 2014 06:00 AM, http://www.consumerreports.org/cro/news/2014/06/are-portableair-conditioner-claims-alot-of-hot-air/index.htm
ES-11

spent in each mode would not change, because no portable AC would be able to cool the room 

adequately and therefore would never cycle off the compressor. 

Table ES.4.5.1 presents the energy use estimated at each efficiency level that DOE is 

considering for portable ACs. Efficiency levels that exceed the baseline level correspond to 

technology options that increase both the EERcm and cooling capacity of portable ACs. When the 

hours spent in cooling mode decreased in a potential standards case compared to the base case, 

DOE allocated the time difference to fan-only mode.

Table ES.4.5.1 Portable ACs: Average Annual Energy Use by Efficiency Level

EL Average EERcm

(Btu/Wh)

Average Cooling 

Capacity 

(Btu/h)

Average Annual 

Residential 

Energy Use

(kWh/year)

Average

Annual 

Commercial Energy 

Use 

(kWh/year)

Baseline 2.08 2,512 724 1,713

1 3.53 4,327 525 1,411

2 4.32 5,293 473 1,330

3 5.28 6,539 434 1,274

4 5.82 6,604 400 1,173

ES.4.6 Life-Cycle Cost and Payback Period Analysis

DOE analyzed the net financial effect on consumers of potential standards for portable 

ACs by evaluating the life-cycle cost (LCC) and payback period (PBP) of the product (chapter 8

of this preliminary analysis TSD). In performing this analysis, DOE used the cost-efficiency 

relationship derived from the engineering and markups analyses, along with the energy costs 

derived from the energy use characterization. Because the operating costs of a more expensive, 

higher-efficiency product may decrease in response to new standards, at some time in the life of 

that product the net savings in operating costs since the time of purchase equal the increase in the 

purchase price of the product. The time required for a product to reach that cost-equivalency 

point is known as the PBP. DOE’s analysis produces a simple PBP based on using single-point 

average values to estimate the purchase price and undiscounted first-year operating cost.

DOE identified several inputs for estimating the LCC and simple PBP, including retail 

prices and installation costs, energy prices, discount rates, and product lifetimes. For portable 

ACs, no information was found to indicate that more efficient portable ACs would have greater 

repair or maintenance costs, so DOE assumed no additional costs would occur. The LCC and 

simple PBP analysis utilized values that reflect unit energy consumption in the field. DOE used 

EIA’s energy price data to determine the range and variability of prices for electricity in 2012, 
ES-12

then used projections of those prices from EIA’s Annual Energy Outlook 2014 to estimate future 

electricity prices. DOE developed discount rates by estimating the finance cost for consumers to 

purchase major appliances. 

Assuming that portable ACs have the same lifetime as room ACs, DOE applied the 

lifetime parameters derived for room ACs to portable ACs. The average lifetime assumed is 10.5

years.

To estimate the percentage of consumers who would be affected by a standard at each 

efficiency level, the LCC analysis considered the projected distribution of efficiencies for

portable ACs purchased under the base case (the case without new energy efficiency standards). 

Lacking industry-supplied data, DOE developed distributions from models and efficiencies listed 

in publically available databases. DOE projected the base-case distributions to the year that 

compliance with any standards would be required (2019). To account for the variability in 

energy consumption and electricity price among users, DOE developed samples of individual 

households and commercial enterprises that use portable ACs. Using the projected distribution of 

efficiencies for each product class, DOE assigned a specific product efficiency to each sample 

household or enterprise. If a household was assigned a product efficiency that equaled or 

exceeded the efficiency of the efficiency level under consideration, the LCC calculation showed 

that the household would be unaffected by that standard level. 

Operating cost savings are a direct function of the size of the room being cooled. 

Households using a portable AC in a room smaller than 250 square feet see relatively large LCC 

savings from the reduction in operating hours. As discussed previously, households using a 

portable AC in a room larger than 250 square feet have fixed operating hours at all efficiency 

levels (independent of cooling capacity). These households incur a net cost from purchasing a 

higher efficiency unit with greater first costs and higher operating costs since the cooling-mode 

power consumption increases with efficiency. This population of households (approximately 30

percent of the sample) has a negative LCC savings. The simple payback uses the average 

installed cost and first year operating cost and reflects the 70 percent of households that see large 

LCC savings from implementation of a standard.

Table ES.4.6.1 through Table ES.4.6.4 show the LCC and simple PBP results for portable 

ACs by efficiency level. The cooling capacities and EERcm’s are presented in chapter 5, based on 

the February 2015 Test Procedure NOPR. DOE determined the median values for the simple 

PBPs by dividing the change in installed cost by the change in first-year operating cost. Figures 

presented in chapter 8 show the range of LCC savings for all the efficiency levels considered.
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Table ES.4.6.1 Summary of LCC and PBP Results by Efficiency Level for Portable ACs at 

Residential Sites

EL

Average Costs 

(2013$) Simple 

Payback

Installed (Years)

Cost

First Year 

Operating 

Cost

Lifetime 

Operating 

Cost

LCC

Baseline 534 101 861 1,394 --

1 540 72 617 1,156 0.21

2 541 64 553 1,094 0.19

3 542 59 505 1,046 0.19

4 605 53 461 1,066 1.52

Note: The average LCC, LCC savings, and simple PBP for each efficiency level are calculated assuming that all 

consumers use products having the given efficiency level. Thus results for all efficiency levels can be compared 

under the same conditions. 

Table ES.4.6.2 Summary of Life-Cycle Costs Relative to the Base-Case Efficiency 

Distribution for Portable ACs at Residential Sites

EL

Life-Cycle Costs and Savings

Average Savings

(2013$)

Percent of Consumers Who

Experience Net Cost

1 212 32

2 271 34

3 319 35

4 300 37

Note: The LCC savings for each efficiency level are calculated relative to the base-case efficiency distribution. The 

calculation includes households that experience zero LCC savings (no impact).
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Table ES.4.6.3 Summary of LCC and PBP Results by Efficiency Level for Portable ACs at 

Commercial Sites

EL

Average Costs 

(2013$) Simple 

Payback

Installed (Years)

Cost

First Year’s 

Operating 

Cost

Lifetime 

Operating 

Cost

LCC

Baseline 534 190 1,351 1884 --

1 540 150 1,066 1606 0.15

2 541 139 9,90 1531 0.13

3 542 131 938 1480 0.13

4 605 117 836 1441 0.98

Note: The average LCC, LCC savings, and simple PBP for each efficiency level are calculated assuming that all 

consumers use products having the given efficiency level. Thus the results for all efficiency levels can be compared 

under the same conditions. 

Table ES.4.6.4 Summary of Life-Cycle Costs and Savings Relative to the Base-Case

Efficiency Distribution for Portable ACs at Commercial Sites

EL

Life-Cycle Costs and Savings

Average Savings

2013$

Percent of Consumers Who

Experience Net Cost

1 253 50

2 326 52

3 376 55

4 415 30

Note: The LCC savings for each efficiency level are calculated relative to the base-case efficiency distribution. The 

calculation includes households that experience zero LCC savings (no impact).

ES.4.7 Shipments Analysis

DOE projects product shipments to calculate the national impacts of potential standards 

on energy use, net present value (NPV) of costs and savings, and manufacturers. DOE used 

historical shipments data for room ACs to populate and calibrate its shipments model for

portable ACs. DOE assumed that shipments of portable ACs account for approximately 10 

percent of total shipments of room ACs. DOE’s shipments model for portable ACs considers 

shipments to replace existing units and to first-time owners. DOE used an accounting method 

that tracks the total stock of units by vintage to determine shipments to the replacement market. 
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Figure ES.4.7.1 shows the projected shipments in the base case and the historical 

shipments DOE used to calibrate those projected shipments. 

Figure ES.4.7.1 Portable ACs Historical Base-Case Shipments and Projection

DOE estimated that annually 0.17 percent of households that have no portable AC would 

purchase one during 2019─2048. Chapter 9 of this preliminary TSD provides additional details 

regarding the shipments analysis.

ES.4.8 National Impact Analysis

The national impact analysis (NIA) estimates impacts on the nation of potential energy 

efficiency standards for portable ACs. Those impacts encompass:

1. national energy savings (NES) attributable to standards;

2. the monetary value of energy savings attributable to standards;

3. the increased total installed costs attributable to standards; and 

4. the NPV of the energy savings attributable to standards (the difference between the 

value of the energy savings and the total installed costs). 

ES.4.8.1 Efficiency Trend

A key component of DOE’s NIA is the projected energy efficiencies of products under 

the base case and each standards case. For the base case, DOE assumed shipments would 

increase annually by 0.25 percent between 2019 and 2048. To examine efficiencies under the 
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potential standards cases, in addition to a “roll-up” scenario (whereby the efficiencies of all 

lower-efficiency portable ACs roll up to meet a new standard), DOE developed a shift scenario. 

In the shift scenario DOE applies an annual increase in average energy efficiency to the 

shipment-weighted cooling energy efficiency ratio (SWEERcm), as done for the base case. To 

develop projected SWEERcm’s for standards cases, DOE developed growth trends for each 

efficiency level that maintained the same per-unit average total installed cost difference for 2019 

between the base case and each standards case throughout the analysis period (2019–2048). In 

developing standards-case SWEERcm’s, DOE assumed that the rate of adoption of more efficient 

products under a standards case can occur only at a rate that ensures a constant average total 

installed cost difference between the standards case and base case throughout the analysis period. 

Because the total installed cost versus efficiency relationship demonstrates an increasing cost for 

more efficient products, the SWEERcm growth rate for each standards case is lower than the 

SWEERcm growth rate for the base case.

Table ES.4.8.1 shows the distributions of base-case and efficiency levels in 2019, based 

on the EERcm for each efficiency level that DOE is considering. The efficiency levels are 

analyzed in the LCC and simple PBP analysis (chapter 8). Also included in the tables are the 

SWEERcm’s associated with the base case and each efficiency level.

Table ES.4.8.1 Portable ACs: Distributions of Base- and Standards-Case Efficiencies in 

2019 for Residential and Commercial Sectors

EL

Average 

Capacity

Average 

EERcm

Market Share (%)

Base 

Case

EL

(Btu/h) (Btu/Wh) 1 2 3 4

Baseline 2,512 2.08 90 0 0 0 0

1 4,327 3.53 5 95 0 0 0

2 5,294 4.32 5 5 100 0 0

3 6,540 5.28 0 0 0 100 0

4 6,604 5.82 0 0 0 0 100

SWEERcm 2.26 3.57 4.32 5.28 5.82

ES.4.8.2 National Energy Savings 

DOE calculated annual NES as the difference between national energy consumption in 

the base case and under each efficiency level. DOE estimated energy consumption and savings 

based on site energy use. DOE then converted site energy consumption and savings to the 

primary energy consumed at power stations to provide the site electricity. Cumulative energy 

savings are the sum of the annual NES. 
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The NES results, shown in Table ES.4.8.2 , are cumulative during the period in which 

units shipped in 2019–2048 are operating. The energy savings, given in quadrillion Btu (quads), 

are shown as primary energy savings.

Table ES.4.8.2 Cumulative Primary National Energy Savings

EL

Portable ACs in 

Residential Sites, 

Primary

(Quads)

Portable ACs in 

Commercial Sites, 

Primary

(Quads)

Portable ACs in both 

sectors, Primary

(Quads)

1 0.526 0.007 0.534

2 0.675 0.010 0.684

3 0.797 0.011 0.809

4 0.917 0.015 0.932

On August 18, 2011, DOE published a statement of policy in the Federal Register

announcing its intention to start using full-fuel-cycle (FFC) measures of energy use and 

greenhouse gas and other emissions in the national impact and emissions analyses in energy 

conservation standards rulemakings. 76 FR 51281; amended by 77 FR 49701 (Aug. 17, 2012). 

Table ES.4.8.3 summarizes the NES for the full-fuel cycle.

Table ES.4.8.3 National Energy Savings for Full-Fuel-Cycle 

EL

Portable ACs in 

Residential Sites, FFC

(Quads)

Portable ACs in 

Commercial Sites, FFC

(Quads)

Portable ACs in both 

sectors, FFC

(Quads)

1 0.551 0.008 0.558

2 0.706 0.010 0.716

3 0.834 0.012 0.846

4 0.959 0.016 0.975

ES.4.8.3 Net Present Value 

DOE calculated the NPV of monetary savings for consumers in each year after potential 

standards would take effect for the base case and each standards case. DOE calculated savings 

throughout the lifetime of products shipped in 2019–2048. DOE used discount rates of 7 percent 

and 3 percent, respectively, to discount future costs and savings to the present. DOE calculated 

the NPV as the difference between the present value of operating cost savings and the present 

value of total installed costs. The NPV results for portable ACs are shown in Table ES.4.8.4 . As 

with the NES results, NPV results are presented as a function of EL.
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Table ES.4.8.4 Cumulative NPV Results Based on 3-Percent and 7-Percent Discount Rates 

EL

Discounted NPV

(Billion 2013$)

3% 7%

Residential Commercial Total Residential Commercial Total

1 3.972 0.060 4.031 1.703 0.026 1.728

2 5.099 0.079 5.178 2.187 0.034 2.221

3 6.022 0.092 6.114 2.581 0.040 2.621

4 6.023 0.113 6.137 2.482 0.048 2.529

ES.4.9 Preliminary Manufacturer Impact Analysis

DOE conducts the manufacturer impact analysis (MIA) in three phases and further tailors

the analytical framework based on comments received from interested parties. In Phase 1, DOE 

creates an industry profile to characterize the industry and conducts preliminary manufacturer 

interviews to identify important issues that require special consideration. The preliminary 

analysis TSD presents the results of the Phase 1 analysis. In Phase 2, DOE prepares an industry 

cash-flow model and an interview questionnaire to guide subsequent discussions. In Phase 3, 

DOE interviews manufacturers and assesses the impacts of new or amended energy conservation 

standards both quantitatively and qualitatively. The NOPR TSD presents the results of Phase 2 

and Phase 3 analyses.

During the preliminary MIA for this rule, DOE identified potential impacts to 

manufacturers of portable ACs through confidential stakeholder interviews. Chapter 12 of the 

preliminary TSD includes details on the key issues identified by DOE during the preliminary 

MIA.

To summarize, DOE identified the following key areas of impact for manufacturers of 

portable ACs:

 Impact on profitability, product mix, and shipments

 Market share, industry consolidation, and competition

 Impact on consumer utility

 Cumulative regulatory burden
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ES.5 Issues on which the Department Seeks Public Comment 

DOE is interested in receiving comments from interested parties on all aspects of this 

preliminary TSD, especially comments or data that might improve DOE’s analyses. DOE 

welcomes data or information that will help resolve the following specific issues, which were 

raised during preparation of this preliminary TSD.

ES.5.1 Portable AC Product Classes

DOE requests comment on the proposed single product class for portable ACs. 

Specifically, DOE seeks feedback on whether its determination that neither duct configuration 

nor product cooling capacity warrant separate product classes, or if there are other product 

characteristics for which multiple product classes would be appropriate.

ES.5.2 Efficiency Levels

DOE developed efficiency levels based on a set of design options which DOE concluded 

would be used at each level and the observed relationship between efficiency and capacity for 

tested and modeled data at each efficiency level configuration. DOE requests comment from 

interested parties on whether these efficiency levels are appropriate for this rulemaking analysis. 

ES.5.3 Design Options and Cost Estimates

As discussed further in chapters 3 through 5 of the preliminary TSD, DOE developed a 

preliminary list of technology options for improving portable AC efficiencies. DOE requests 

feedback on whether there are additional technologies available that may improve portable AC

performance. DOE also seeks comment on whether the MPCs at each efficiency level are 

appropriate given the associated incremental changes manufacturers would likely make to meet 

these levels. 

ES.5.4 Lifetime of Portable ACs

DOE found few data regarding portable AC lifetimes. Currently, DOE assumes that the 

lifetime of a portable AC is equal to the 10-year lifetime of a room AC. One could assume that, 

given their comparatively lower usage, portable ACs would have longer lifetimes than room 

ACs. DOE requests input on its proposed lifetime for portable ACs.

ES.5.5 Energy Use Determination

DOE’s literature review performed to establish a distribution of energy use values for

portable ACs revealed few data pertaining to how portable ACs are operated in the field. DOE 

relied on usage information for room ACs to establish operating hours for portable ACs. DOE 

assumed that the distribution of hours of use calculated for room ACs represented the hours of 
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use in cooling mode for a baseline portable AC unit. DOE requests input on its proposed method 

for determining usage hours and energy use.

ES.5.6 Operating Hours for a Standards Case

In its energy use calculation DOE assumed that the square footage of the room being 

cooled would affect the operating hours of a portable AC in a standards case in which a highercapacity unit replaces a lower-capacity unit. DOE assumed that if the room was smaller than 250 

square feet, the portable AC’s operating hours in cooling mode would be reduced; if the room 

was larger than 250 square feet, operating hours in cooling mode would not change in response 

to a higher-capacity unit. DOE requests input regarding this assumption.

ES.5.7 Commercial Use of Portable ACs

DOE’s data and literature review revealed no information on energy use of portable ACs 

in commercial enterprises or on shipments of portable ACs to commercial enterprises. DOE 

requests that interested parties provide data and literature to characterize the market saturation 

and energy use of portable ACs in commercial settings.

ES.5.8 Historical Shipments of Portable ACs

DOE’s review of data and literature uncovered no information on shipments of portable 

ACs. DOE requests that interested parties provide any available data and literature for 

characterizing historical shipments of portable ACs.