5-i

CHAPTER 5. ENGINEERING ANALYSIS

TABLE OF CONTENTS

5.1 INTRODUCTION................................................................................................................ 5-1

5.2 EQUIPMENT CLASSES..................................................................................................... 5-1

5.2.1 Representative Input Capacities........................................................................... 5-3

5.3 EFFICIENCY LEVELS ANALYZED ................................................................................ 5-3

5.3.1 Baseline Efficiency Levels .................................................................................. 5-3

5.3.2 Max-tech Efficiency Levels................................................................................. 5-4

5.3.3 Intermediate Efficiency Levels............................................................................ 5-5

5.4 METHODOLOGY............................................................................................................... 5-8

5.4.1 Data Collection .................................................................................................... 5-8

5.4.2 Mechanical Draft Non-Condensing Boilers......................................................... 5-9

5.4.3 Mechanical Draft Condensing Boilers (Hot water Equipment Classes Only)... 5-10

5.4.4 Natural Draft Boilers.......................................................................................... 5-10

5.5 RESULTS........................................................................................................................... 5-11

5.5.1 Graphical Representation of Results.................................................................. 5-13
5-ii

LIST OF FIGURES

Figure 5.5.1. Price-Efficiency Relationship for Small Gas-Fired Natural Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-14

Figure 5.5.2. Price-Efficiency Relationship for Large Gas-Fired Natural Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-14

Figure 5.5.3. Price-Efficiency Relationship for Small Oil-Fired Natural Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-14

Figure 5.5.4. Price-Efficiency Relationship for Large Oil-Fired Natural Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-15

Figure 5.5.5. Price-Efficiency Relationship for Small Gas-Fired Natural Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-15

Figure 5.5.6. Price-Efficiency Relationship for Large Gas-Fired Natural Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-15

Figure 5.5.7. Price-Efficiency Relationship for Small Oil-Fired Natural Draft Steam Commercial 

Packaged Boilers........................................................................................................................ 5-16

Figure 5.5.8: Price-Efficiency Relationship for Large Oil-Fired Natural Draft Steam Commercial 

Packaged Boilers........................................................................................................................ 5-16

Figure 5.5.9. Price-Efficiency Relationship for Small Gas-Fired Mechanical Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-16

Figure 5.5.10. Price-Efficiency Relationship for Large Gas-Fired Mechanical Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-17

Figure 5.5.11. Price-Efficiency Relationship for Small Oil-Fired Mechanical Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-17

Figure 5.5.12. Price-Efficiency Relationship for Large Oil-Fired Mechanical Draft Hot Water 

Commercial Packaged Boilers................................................................................................... 5-17

Figure 5.5.13. Price-Efficiency Relationship for Small Gas-Fired Mechanical Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-18

Figure 5.5.14. Price-Efficiency Relationship for Large Gas-Fired Mechanical Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-18

Figure 5.5.15. Price-Efficiency Relationship for Small Oil-Fired Mechanical Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-18

Figure 5.5.16. Price-Efficiency Relationship for Large Oil-Fired Mechanical Draft Steam 

Commercial Packaged Boilers................................................................................................... 5-19
5-iii

LIST OF TABLES

Table 5.2.1. Equipment Classes Considered by the Department of Energy for the Preliminary 

Analysis........................................................................................................................................ 5-2

Table 5.3.1. Baseline Efficiencies for All Equipment Classes.................................................... 5-4

Table 5.3.2. Natural Draft - Small Gas-Fired Hot Water Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-5

Table 5.3.3. Natural Draft - Large Gas-Fired Hot Water Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-5

Table 5.3.4. Natural Draft - Small Oil-Fired Hot Water Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-5

Table 5.3.5. Natural Draft - Large Oil-Fired Hot Water Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-6

Table 5.3.6. Natural Draft - Small Gas-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-6

Table 5.3.7. Natural Draft - Large Gas-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-6

Table 5.3.8. Natural Draft - Small Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-6

Table 5.3.9. Natural Draft - Large Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-6

Table 5.3.10. Mechanical Draft - Small Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-6

Table 5.3.11. Mechanical Draft - Large Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-7

Table 5.3.12. Mechanical Draft - Small Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-7

Table 5.3.13. Mechanical Draft - Large Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-7

Table 5.3.14. Mechanical Draft - Small Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-7

Table 5.3.15. Mechanical Draft - Large Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels......................................................................................................................... 5-7

Table 5.3.16. Mechanical Draft - Small Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-7

Table 5.3.17. Mechanical Draft - Large Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels........................................................................................................................................... 5-8

Table 5.5.1. Incremental and Baseline Prices for all Natural Draft Equipment Classes for 

Commercial Packaged Boilers................................................................................................... 5-11

Table 5.5.2. Incremental and Baseline Costs for all Mechanical Draft Equipment Classes for 

Commercial Packaged Boilers................................................................................................... 5-12
5-1

CHAPTER 5. ENGINEERING ANALYSIS

5.1 INTRODUCTION

The engineering analysis establishes the relationship between equipment prices and

energy-efficiency of commercial packaged boilers (CPBs). The price-efficiency relationship 

serves as a basis for subsequent cost/benefit calculations for individual customers, 

manufacturers, and the Nation. 

To determine the industry price-efficiency relationship, the U.S. Department of Energy 

(DOE) uses data from the chapter 3, market and technology assessment, publicly available 

equipment literature and research reports, and information from manufacturers and installers. 

DOE subsequently collected commercial packaged boiler prices primarily from data provided by 

manufacturers, mechanical contractors, and equipment distributors, and categorized contractor 

prices by thermal and combustion efficiency, output capacity, input fuel, type of heating output 

(i.e., hot water or steam), and the type of boiler draft system (atmospheric or other). DOE used 

this data along with rated performance data obtained from the Air-conditioning, Heating and 

Refrigeration Institute’s (AHRI’s) Directory of Certified Product Performance for commercial 

boilers to carry out the engineering analysis.1

The methodology adopted for the engineering analysis generally involves calculating 

prices of commercial packaged boilers for a given input rating (representative capacity) for each 

manufacturer at an efficiency level higher than the minimum allowable standard (baseline 

efficiency). The primary output of the analysis is a set of price-efficiency relationships that 

represent the average change in price for higher efficiency equipment (i.e., “incremental price”). 

In the subsequent markups analysis (chapter 6 in the preliminary Technical Support Document 

(TSD)), DOE determines customer prices by applying distribution markups, sales tax, and 

contractor markups to the manufacturer sales prices developed in the engineering analysis. After 

applying these markups, the data serve as inputs to the energy use characterization (chapter 7 in 

the preliminary TSD) and the life-cycle cost and payback period analyses (chapter 8 in the 

preliminary TSD).

In this chapter, DOE discusses: (1) the equipment classes it analyzed, (2) the 

identification of representative baseline units and efficiency levels above the baseline, (3) the 

methodology for calculating price-efficiency relationships, and (4) the results of the analysis.

5.2 EQUIPMENT CLASSES

Existing energy conservation standards, set forth in section 431.87 of subpart E of Title 

10 of the Code of Federal Regulations, Part 431 (10 CFR Part 431), classify CPBs into ten 

equipment classes. The boilers are classified based on three performance parameters: (1) input 

capacity (small (≥300kBtu/h to ≤2500kBtu/h) or large (>2500kBtu/h)), (2) fuel type (gas or oil),

and (3) heating media (hot water or steam). Using the three parameters, eight equipment classes 

can be formed. The remaining two equipment classes are created by further classifying gas-fired 

steam boilers based on draft type (mechanical draft or natural draft). These ten equipment classes 

have also been described in chapter 3 of this preliminary TSD.
5-2

On August 13, 2013, DOE published in the Federal Register a proposed determination of 

coverage for natural draft commercial packaged boilers which would explicitly clarify DOE’s

statutory authority under EPCA to cover natural draft commercial packaged boilers. 78 FR 

49202. As discussed in chapter 3 of this preliminary TSD, if the outcome of the proposed 

determination is positive, DOE will create separate equipment classes and energy conservation 

standards for natural draft CPBs. Although the outcome is pending, for the current rulemaking 

analysis, DOE has separated CPBs based on draft type (i.e., natural draft or mechanical draft). 

Thus, if the determination is ultimately positive, it would add six new equipment classes to the 

existing ones set forth in 10 CFR Part 431. The Table 5.2.1 below shows the list of all 

equipment classes analyzed for this preliminary analysis. Further details about the classifications

are provided in chapter 3 – Market and Technology Assessment.

Table 5.2.1. Equipment Classes Considered by the Department of Energy for the 

Preliminary Analysis

Draft 

Type Size Category Fuel Type

Heating 

Medium Full Name

Natural 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Gas-fired Hot Water Small Gas-fired Natural Draft Hot Water CPB

Natural 

Draft Large (>2,500,000 Btu/h) Gas-fired Hot Water Large Gas-fired Natural Draft Hot Water CPB

Natural 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Oil-fired Hot Water Small Oil-fired Natural Draft Hot Water CPB

Natural 

Draft Large (>2,500,000 Btu/h) Oil-fired Hot Water Large Oil-fired Natural Draft Hot Water CPB

Natural 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Gas-fired Steam Small Gas-fired Natural Draft Steam CPB

Natural 

Draft Large (>2,500,000 Btu/h) Gas-fired Steam Large Gas-fired Natural Draft Steam CPB

Natural 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Oil-fired Steam Small Oil-fired Natural Draft Steam CPB

Natural 

Draft Large (>2,500,000 Btu/h) Oil-fired Steam Large Oil-fired Natural Draft Steam CPB

Mechanical 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Gas-fired Hot Water Small Gas-fired Mechanical Draft Hot Water CPB

Mechanical 

Draft Large (>2,500,000 Btu/h) Gas-fired Hot Water Large Gas-fired Mechanical Draft Hot Water CPB

Mechanical 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Oil-fired Hot Water Small Oil-fired Mechanical Draft Hot Water CPB

Mechanical 

Draft Large (>2,500,000 Btu/h) Oil-fired Hot Water Large Oil-fired Mechanical Draft Hot Water CPB

Mechanical 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Gas-fired Steam Small Gas-fired Mechanical Draft Steam CPB

Mechanical 

Draft Large (>2,500,000 Btu/h) Gas-fired Steam Large Gas-fired Mechanical Draft Steam CPB

Mechanical 

Draft

Small (≥300,000 Btu/h and 

≤2,500,000 Btu/h) Oil-fired Steam Small Oil-fired Mechanical Draft Steam CPB

Mechanical 

Draft Large (>2,500,000 Btu/h) Oil-fired Steam Large Oil-fired Mechanical Draft Steam CPB
5-3

5.2.1 Representative Input Capacities

Efficiency and input ratings are two major factors which influence boiler prices. The two 

factors are mutually independent of each other and depend mostly on the physical characteristics 

of the boiler such as size, gas/oil flow rate, heat exchanger capability, etc. The impact of 

efficiency ratings on boiler price can be captured by calculating incremental price for each

efficiency level higher than the baseline at a given input rating.

. 

Therefore, to provide a singular set of incremental price results for the engineering 

analysis, DOE selected for each equipment class a single input capacity to represent the entire 

equipment class. The representative capacity essentially corresponds to the boiler capacity that

has the highest number of shipments in any given year. Using a representative capacity enables 

DOE to analyze certain equipment characteristics for proxy information about the entire

equipment class.

For the preliminary analysis, DOE selected 800kBtu/h as the representative capacity for

small boilers (≥300kBtu/h to ≤2,500kBtu) and 3,000kBtu/h for large boilers (>2,500kBtu/h). 

DOE chose these levels by taking into account a number of sources, such as previous rulemaking

analyses, information obtained during manufacturer interviews, information collected for the 

market and technology assessment, equipment product literature, and discussions with industry 

experts.

5.3 EFFICIENCY LEVELS ANALYZED

5.3.1 Baseline Efficiency Levels

DOE selected baseline efficiency levels as reference points for each equipment class, 

against which DOE calculates potential changes in energy use, cost, and utility that could result 

from an amended energy conservation standard. The energy conservation standards for CPBs, 

under subpart E of 10 CFR Part 431, represent required efficiency levels for such equipment to 

be distributed in commerce in the U.S. Typically, a baseline unit is one that meets, but does not 

exceed, the required energy conservation standard, as applicable, and provides basic consumer 

utility. Each efficiency standard specified in 10 CFR 431.87 serves as a basis or reference point 

to calculate any incremental price to achieve a higher efficiency level and referred to as the 

“baseline efficiency.” A boiler model that has a rated efficiency equal to its applicable baseline 

efficiency is referred to as a “baseline model.”

DOE uses the baseline model for comparison in several phases of the analyses, including 

the engineering analysis, lifecycle cost (LCC) analysis, payback period (PBP) analysis and 

national impacts analysis (NIA). To determine energy savings that will result from an amended 

energy conservation standard, DOE compares energy use at each of the higher energy efficiency 

levels to the energy use of the baseline model. Similarly, to determine the changes in price to the 

customer that will result from an amended energy conservation standard, DOE compares the 

price of a baseline model to the price of a model at each higher efficiency level.
5-4

As part of its analyses DOE also conducts a review of common boiler technology features 

present in baseline models and compares them with technology features of higher efficiency 

models. This helps DOE validate any incremental prices for higher efficiency models. Table 

5.3.1 below shows the 16 equipment classes and their baseline efficiencies.

Table 5.3.1. Baseline Efficiencies for All Equipment Classes

Equipment 

Type

Draft 

Type Fuel Type Size Category Baseline Efficiency*

Hot Water Natural 

Draft Gas-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 80% ET

Hot Water Natural 

Draft Gas-fired Large (>2,500,000Btu/h) 82% EC

Hot Water Natural 

Draft Oil-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 82% ET

Hot Water Natural 

Draft Oil-fired Large (>2,500,000Btu/h) 84% EC

Steam Natural 

Draft Gas-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 77% ET

Steam Natural 

Draft Gas-fired Large (>2,500,000Btu/h) 77% ET

Steam Natural 

Draft Oil-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 81% ET

Steam Natural 

Draft Oil-fired Large (>2,500,000Btu/h) 81% ET

Hot Water Mechanical 

Draft Gas-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 80% ET

Hot Water Mechanical 

Draft Gas-fired Large (>2,500,000Btu/h) 82% EC

Hot Water Mechanical 

Draft Oil-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 82% ET

Hot Water Mechanical 

Draft Oil-fired Large (>2,500,000Btu/h) 84% EC

Steam Mechanical 

Draft Gas-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 79% ET

Steam Mechanical 

Draft Gas-fired Large (>2,500,000Btu/h) 79% ET

Steam Mechanical 

Draft Oil-fired Small (≥300,000Btu/h and 

≤2,500,000Btu/h) 81% ET

Steam Mechanical 

Draft Oil-fired Large (>2,500,000Btu/h) 81% ET

*ET means Thermal Efficiency and Ec means Combustion Efficiency

5.3.2 Max-tech Efficiency Levels

As part of its engineering analysis, DOE determined the maximum technologically 

feasible (“max-tech”) improvement in energy efficiency for commercial packaged boilers as 

required under section 342 of EPCA. (42 U.S.C. 6313(a)(6)(A)(ii)(II)) DOE surveyed the CPB

market and the research fields that support that market. The DOE-determined max-tech levels for 
5-5

the engineering analysis are shown in Table 5.3.2. through Table 5.3.17, and correspond to the 

maximum efficiency that is commercially available.

5.3.3 Intermediate Efficiency Levels

In the engineering analysis, DOE generally identifies, for each equipment class, several 

efficiency levels between the baseline efficiency level and max-tech efficiency level. The 

efficiency levels typically represent the most common efficiencies on the market or a major 

design change (e.g., switching to a condensing heat exchanger). DOE identifies several 

efficiency levels for each equipment class based on an extensive review of publicly available 

CPB equipment literature and the 2013 AHRI Directory of Certified Product Performance. 

Table 5.3.2. through Table 5.3.17 show the efficiency levels analyzed for each equipment class.

Table 5.3.2. Natural Draft - Small Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 80

Efficiency Level 1 81

Efficiency Level 2 82

Efficiency Level 3 (Max-tech) 85

Table 5.3.3. Natural Draft - Large Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Combustion Efficiency(%)

Efficiency Level 0 (Baseline) 82

Efficiency Level 1 83

Efficiency Level 2 (Max-tech) 84

Table 5.3.4. Natural Draft - Small Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 82

Efficiency Level 1 83

Efficiency Level 2 85

Efficiency Level 3 (Max-tech) 87
5-6

Table 5.3.5. Natural Draft - Large Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Combustion Efficiency (%)

Efficiency Level 0 (Baseline) 84

Efficiency Level 1 85

Efficiency Level 2 (Max-tech) 86

Table 5.3.6. Natural Draft - Small Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 77

Efficiency Level 1 79

Efficiency Level 2 (Max-tech) 80

Table 5.3.7. Natural Draft - Large Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 77

Efficiency Level 1 79

Efficiency Level 2 80

Efficiency Level 3 (Max-tech) 81

Table 5.3.8. Natural Draft - Small Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels

Efficiency Level Thermal Efficiency (%)

Baseline Efficiency Level 0 (Baseline) 81

Efficiency Level 1 82

Efficiency Level 2 (Max-tech) 83

Table 5.3.9. Natural Draft - Large Oil-Fired Steam Commercial Packaged Boiler Efficiency 

Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 81

Efficiency Level 1 82

Efficiency Level 2 83

Efficiency Level 3 (Max-tech) 85

Table 5.3.10. Mechanical Draft - Small Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 80

Efficiency Level 1 83

Efficiency Level 2 85

Efficiency Level 3 87

Efficiency Level 4 92

Efficiency Level 5 95
5-7

Efficiency Level 6 (Max-tech) 98

Table 5.3.11. Mechanical Draft - Large Gas-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Combustion Efficiency (%)

Efficiency Level 0 (Baseline) 82

Efficiency Level 1 84

Efficiency Level 2 86

Efficiency Level 3 94

Efficiency Level 4 (Max-tech) 97

Table 5.3.12. Mechanical Draft - Small Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 82

Efficiency Level 1 83

Efficiency Level 2 84

Efficiency Level 3 87

Efficiency Level 4 (Max-tech) 98

Table 5.3.13. Mechanical Draft - Large Oil-Fired Hot Water Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Combustion Efficiency (%)

Efficiency Level 0 (Baseline) 84

Efficiency Level 1 86

Efficiency Level 2 88

Efficiency Level 3 (Max-tech) 97

Table 5.3.14. Mechanical Draft - Small Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 79

Efficiency Level 1 80

Efficiency Level 2 81

Efficiency Level 3 (Max-tech) 83

Table 5.3.15. Mechanical Draft - Large Gas-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 79

Efficiency Level 1 80

Efficiency Level 2 (Max-tech) 83

Table 5.3.16. Mechanical Draft - Small Oil-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 81
5-8

Efficiency Level 1 83

Efficiency Level 2 84

Efficiency Level 3 (Max-tech) 86

Table 5.3.17. Mechanical Draft - Large Oil-Fired Steam Commercial Packaged Boiler 

Efficiency Levels

Efficiency Level Thermal Efficiency (%)

Efficiency Level 0 (Baseline) 81

Efficiency Level 1 83

Efficiency Level 2 (Max-tech) 86

DOE used these efficiency levels in the analysis as target efficiencies for calculating 

incremental price of achieving increased efficiency. The incremental price refers to the 

additional price that the first customer in the distribution chain would have to pay for higher 

efficiency equipment.

5.4 METHODOLOGY 

This section describes the analytical methodology DOE used in the engineering analysis.

DOE collected and compiled CPB pricing information and categorized all the boiler models into 

the 16 equipment classes. For equipment classes where limited pricing information was 

available, DOE used different statistical inference techniques to calculate incremental prices. The

DOE methodology to calculate incremental prices is based on characteristics of boilers of each

equipment class (such as condensing or non-condensing and natural or mechanical draft) and the 

pricing information that it was able to collect.

Generally, DOE categorizes prices based on manufacturers and separately calculates

incremental prices for each manufacturer. For the large CPB equipment classes, DOE was unable 

to collect a significant amount of pricing information, so in some cases DOE considered the price 

of two small boilers having an input capacity of 1500kBtu/h to match the 3,000kBtu/h 

representative capacity for large boilers. This helped to expand the available data for large 

boilers, which improved the accuracy of the results.

5.4.1 Data Collection

DOE identified commercial packaged boiler models for each equipment class at each 

representative input capacity and across a range of efficiencies. The models DOE identified 

include various designs and materials (e.g., cast iron, copper, aluminum) in their respective heat 

exchangers. Through discussion with manufacturers, distributors, and mechanical contractors, 

DOE obtained the contractor prices for commercial packaged boiler models at various efficiency 

levels for a variety of commercial boiler types and configurations. DOE also obtained contractor 

markup percentages, which refer to the profit and overhead margins of contractors. These 

markups were discounted from the prices to estimate manufacturer prices. The majority of the 

data that DOE collected were in the small, gas-fired, hot water, mechanical draft equipment 

class. DOE also collected a limited amount of data for the rest of the mechanical draft equipment 

classes. In the natural draft equipment classes, most of the available data were for small gas-fired 

natural draft equipment classes. Apart from this, there were only limited data available for the 

remainder of the natural draft equipment classes.
5-9

5.4.2 Mechanical Draft Non-Condensing Boilers

For most equipment classes of mechanical draft boilers, DOE obtained prices for different 

CPBs at a variety of input ratings and efficiency levels, which allowed DOE to estimate the 

average price of a CPB at each efficiency level. As a first step, DOE isolated data that were

collected at the “representative” input capacity discussed in section 5.2.1 of this chapter. DOE 

then subtracted the prices of all higher efficiency models at the representative input from the 

baseline price at the representative input for each manufacturer to determine the incremental 

price increase for higher efficiency equipment from each manufacturer. DOE took an average of 

all the incremental prices at every efficiency level to arrive at the final average incremental price

of achieving each efficiency level. DOE used this approach to analyze the following equipment 

classes: 

1) Small gas-fired mechanical draft hot water boilers (SGMDHW) – Non-condensing

efficiency levels only

2) Large gas-fired mechanical draft hot water boilers (LGMDHW) – Non-condensing

efficiency levels only

3) Small oil-fired mechanical draft hot water boilers (SOMDHW) – Non-condensing

efficiency levels only

4) Large oil-fired mechanical draft hot water boilers (LOMDHW) – Non-condensing

efficiency levels only

5) Small gas-fired mechanical draft steam boilers (SGMDST)a

6) Small oil-fired mechanical draft steam boilers (SOMDST)a

In some cases prices were not available for all efficiency levels being analyzed. 

However, in such cases, DOE had efficiency information both at levels above and below the 

analyzed level. In such cases, DOE used regression analysis to infer the prices at the efficiency 

level being analyzed. For example, if DOE was analyzing 83 percent thermal efficiency and had 

pricing information for 82 percent, 84 percent and 85 percent thermal efficiency models from a 

given manufacturer, a regression would be used to estimate the price of an 83 percent model 

from that manufacturer. Using this approach DOE was able to approximate prices for all 

efficiency levels from each manufacturer. For two of the mechanical draft commercial packaged 

boiler equipment classes – large gas-fired mechanical draft steam (LGMDST) boilers and large 

oil-fired mechanical draft steam (LOMDST) boiler – DOE was unable to collect adequate

pricing information to conduct an analysis as described above. For these two classes, the priceefficiency relationship was estimated based on other similar equipment classes. To analyze these 

classes, DOE first took the ratio of incremental prices between large gas-fired hot water 

equipment classes and small gas-fired hot water equipment classes for each efficiency level. This 

ratio was multiplied by the incremental price for each efficiency level for small gas-fired 

mechanical draft steam boilers and small oil-fired mechanical draft steam boilers. The product of 

the two numbers was assumed to be the incremental prices for large gas-fired steam boilers and 

 a Equipment classes with steam as a heating medium include only non-condensing boilers.
5-10

large oil-fired steam boilers. The incremental prices were then calculated by subtracting the 

higher efficiency prices from the baseline prices.

Condensing boilers were analyzed separately from non-condensing boilers because of 

three considerations: (1) A condensing boiler has an additional secondary or a primary heat 

exchanger made of corrosion resistant materials to allow condensation of water vapor from flue 

gasses. This feature makes it distinct from a conventional commercial packaged boiler; (2) The

price transition from a non-condensing to a condensing boiler is generally not necessarily 

smooth‒there is a step change in price from a non-condensing boiler to a condensing boiler; and 

(3) As observed from price data, the slope of the price-efficiency relationship for all condensing 

efficiency levels is generally steeper than all non-condensing efficiency levels. 

5.4.3 Mechanical Draft Condensing Boilers (Hot water Equipment Classes Only)

Efficiency levels above 90 percent represent condensing boiler efficiencies. These 

efficiency levels were present in four of the mechanical draft, hot water equipment classes –

small gas-fired boilers (SGMDHW), large gas-fired boilers (LGMDHW), small oil-fired boilers

(SOMDHW) and large oil-fired boilers (LOMDHW).

LGMDHW condensing boilers did not require any special considerations for analyses. 

Sufficient pricing information was available, which enabled DOE to analyze these boilers using 

the same approach as illustrated above for non-condensing boilers.

For SGMDHW condensing boilers, certain special considerations were made by DOE. 

The methodology for calculating incremental price for this equipment class involved an 

additional step to consider the price impacts of different heat exchanger materials. Generally, 

materials such as copper, aluminum, and stainless steel are used for making condensing boilers. 

DOE took the average of prices of all manufacturers producing condensing boilers having the

same material type, for every efficiency level. This resulted in a single representative price for 

each efficiency level based on the material type. Prices of higher efficiency models were 

subtracted from the baseline within each material category. The final average incremental price

for equipment at each higher efficiency level was calculated by taking an average of the 

incremental prices across all of the heat exchanger materials.

SOMDHW and LOMDHW condensing boilers were also analyzed separately. Due to the 

relatively small market for condensing oil-fired equipment, DOE was unable to obtain pricing 

information for condensing boiler models in these equipment classes. As a result, the price of 

condensing oil-fired CPBs were inferred by DOE based on price efficiency equations for 

SGMDHW and LGMDHW boilers. The ratio of the slope (of the price-efficiency curve) between

non-condensing and condensing boilers was assumed to be the same for all small and large type 

equipment classes, respectively. DOE used this slope ratio and the slope of the equation for noncondensing boilers (for SOMDHW and LOMDHW) to deduce the relationship for the priceefficiency curve for condensing boilers of these equipment classes.

5.4.4 Natural Draft Boilers

DOE was able to collect a limited amount of pricing information for natural draft boilers. 

To calculate incremental prices for such equipment classes, DOE first assessed the component 

level differences between mechanical draft and natural draft boilers. While mechanical draft 
5-11

systems have a blower or fan that mechanically assists in creating draft to expel the by-products 

of combustion, natural draft systems typically include a draft hood which allows flue gases to 

vent out to the atmosphere using only the natural buoyancy effect. For calculating natural draft 

prices, DOE compared the price differential between mechanical draft components (such as fans 

or blowers) and natural draft components (such as stack dampers and a draft hood) for a same 

sized boiler. This price differential was subtracted from mechanical draft boiler prices to estimate

natural draft boiler prices for corresponding equipment classes. For example, the small gas-fired 

natural draft hot water equipment prices were calculated by subtracting the differential price 

(between a mechanical draft system and a natural draft system) from small gas-fired mechanical 

draft hot water boiler prices. This method was applied to all natural draft equipment classes to 

obtain pricing estimates for natural draft CPBs. The results were then validated by comparing 

the estimated price-efficiency results to the limited pricing data that was collected for natural 

draft CPBs. Incremental prices were then obtained by subtracting prices for higher efficiency 

levels from the corresponding baseline prices. The equipment classes analyzed using the 

aforementioned methodologies are listed below:

1) Small gas-fired natural draft hot water boilers (SGNDHW)

2) Large gas-fired natural draft hot water boilers (LGNDHW)

3) Small oil-fired natural draft hot water boilers (SONDHW) 

4) Large oil-fired natural draft hot water boilers (LONDHW) 

5) Small gas-fired natural draft steam boilers (SGNDST)

6) Large gas-fired natural draft steam boilers (LONDST) 

7) Small oil-fired natural draft steam boilers (SONDST)

8) Large oil-fired natural draft steam boilers (LONDST) 

5.5 RESULTS

The final result of the engineering analysis is a set of price-efficiency relationships. DOE 

developed these relationships for all sixteen equipment classes of commercial packaged boilers 

using the methodologies described in the previous section. In the rulemaking process, the results 

obtained from the engineering analysis chapter are utilized further to conduct all subsequent 

analyses, such as life-cycle cost (LCC) analysis, energy use analysis, and so forth. In general, 

results from the engineering analysis show an increasing trend for incremental price for 

achieving higher efficiency. Table 5.5.1. and Table 5.5.2. below show the incremental and 

baseline price for all natural and mechanical draft equipment classes. 

Table 5.5.1. Incremental and Baseline Prices for all Natural Draft Equipment Classes for 

Commercial Packaged Boilers

NATURAL DRAFT

Product Class Efficiency Level Incremental 

Price Baseline Price
5-12

Small Gas-fired Hot Water, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

80% $0

$ 3,799

81% $529

82% $1,307

85% $3,078

Large Gas-fired Hot Water, 

>2,500,000 Btu/hr

82%* $0

83%* $2,075 $ 16,898

84%* $4,343

Small Oil-fired Hot Water, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

82% $0

$ 5,486

83% $395

85% $3,282

87% $3,654

Large Oil-fired Hot Water, >2,500,000 

Btu/hr

84%* $0

85%* $2,300 $ 15,845

86%* $4,138

Small Gas-fired Steam, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

77% $0

79% $1,601 $ 3,215

80% $2,661

Large Gas-fired Steam, >2,500,000 

Btu/hr

77% $0

$ 5,248

79% $3,858

80% $7,392

81% $11,334

Small Oil-fired Steam, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

81% $0

82% $1,046 $ 5,286

83% $2,204

Large Oil-fired Steam, >2,500,000 

Btu/hr

81% $0

$ 7,998 82% $2,966

83% $6,250

85% $13,892

* Efficiency levels mentioned are combustion efficiency

Table 5.5.2. Incremental and Baseline Costs for all Mechanical Draft Equipment Classes 

for Commercial Packaged Boilers

MECHANICAL DRAFT

Product Class Efficiency Level Incremental 

Price Baseline Price

Small Gas-fired Hot Water, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

80% $0

$ 7,120

83% $1,710

85% $3,078

87% $4,665

92% $6,819
5-13

95% $11,211

98% $15,604

Large Gas-fired Hot Water, 

>2,500,000 Btu/hr

82%* $0

$ 22,256

84%* $4,343

86%* $9,533

94%* $31,784

97%* $35,892

Small Oil-fired Hot Water, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

82% $0

$ 8,806

83% $814

84% $1,629

87% $4,073

98% $18,943

Large Oil-fired Hot Water, >2,500,000 

Btu/hr

84%* $0

$ 21,203

86%* $5,348

88%* $8,459

97%* $47,635

Small Gas-fired Steam, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

79% $0

$ 8,136

80% $1,060

81% $2,243

83% $5,025

Large Gas-fired Steam, >2,500,000 

Btu/hr

79% $0

80% $3,534 $ 14,464

83% $16,750

Small Oil-fired Steam, ≥ 300,000 

Btu/hr and ≤ 2,500,000 Btu/hr

81% $0

$ 8,607

83% $2,204

84% $3,485

86% $6,461

Large Oil-fired Steam, >2,500,000 

Btu/hr

81% $0

83% $6,250 $ 13,355

86% $18,316

* Efficiency levels mentioned are combustion efficiency

5.5.1 Graphical Representation of Results

Figure 5.5.1 to Figure 5.5.16 below show a graphical representation of the relationship 

between incremental price and efficiency for each equipment class.
5-14

Figure 5.5.1. Price-Efficiency Relationship for Small Gas-Fired Natural Draft Hot Water 

Commercial Packaged Boilers

Figure 5.5.2. Price-Efficiency Relationship for Large Gas-Fired Natural Draft Hot Water 

Commercial Packaged Boilers

Figure 5.5.3. Price-Efficiency Relationship for Small Oil-Fired Natural Draft Hot Water

Commercial Packaged Boilers

$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

$3,500

79% 80% 81% 82% 83% 84% 85% 86%

Incremental Price [$]

Thermal Efficiency [%]

SGNDHW Price-Efficiency Curve

$0

$1,000

$2,000

$3,000

$4,000

$5,000

82% 82% 83% 83% 84% 84% 85%

Incremental Price [$]

Combustion Efficiency [%]

LGNDHW Price-Efficiency Curve

$0

$1,000

$2,000

$3,000

$4,000

81% 82% 83% 84% 85% 86% 87% 88%

Incremental Price [$]

Thermal Efficiency [%]

SONDHW Price-Efficiency Curve
5-15

Figure 5.5.4. Price-Efficiency Relationship for Large Oil-Fired Natural Draft Hot Water 

Commercial Packaged Boilers

Figure 5.5.5. Price-Efficiency Relationship for Small Gas-Fired Natural Draft Steam 

Commercial Packaged Boilers

Figure 5.5.6. Price-Efficiency Relationship for Large Gas-Fired Natural Draft Steam 

Commercial Packaged Boilers

$0

$1,000

$2,000

$3,000

$4,000

$5,000

84% 84% 85% 85% 86% 86% 87%

Incremental Price [$]

Combustion Efficiency [%]

LONDHW Price-Efficiency Curve

$0

$500

$1,000

$1,500

$2,000

$2,500

$3,000

77% 77% 78% 78% 79% 79% 80% 80% 81%

Incremental Price [$]

Thermal Efficiency [%]

SGNDST Price-Efficiency Curve

$0

$2,000

$4,000

$6,000

$8,000

$10,000

$12,000

Incremental 

76% 77% 78% 79% 80% 81% 82%

Price [$]

Thermal Efficiency [%]

LGNDST Price-Efficiency Curve
5-16

Figure 5.5.7. Price-Efficiency Relationship for Small Oil-Fired Natural Draft Steam 

Commercial Packaged Boilers

Figure 5.5.8: Price-Efficiency Relationship for Large Oil-Fired Natural Draft Steam 

Commercial Packaged Boilers

Figure 5.5.9. Price-Efficiency Relationship for Small Gas-Fired Mechanical Draft Hot 

Water Commercial Packaged Boilers

$0

$500

$1,000

$1,500

$2,000

$2,500

81% 81% 82% 82% 83% 83% 84%

Incremental Price [$]

Thermal Efficiency [%]

SONDST Price-Efficiency Curve

$0

$5,000

$10,000

$15,000

80% 81% 82% 83% 84% 85% 86%

Incremental Price [$]

Thermal Efficiency [%]

LONDST Price-Efficiency Curve

$0

$4,000

$8,000

$12,000

$16,000

$20,000

80% 85% 90% 95% 100%

Incremental Price [$]

Thermal Efficiency [%]

SGMDHW Price-Efficiency Curve
5-17

Figure 5.5.10. Price-Efficiency Relationship for Large Gas-Fired Mechanical Draft Hot 

Water Commercial Packaged Boilers

Figure 5.5.11. Price-Efficiency Relationship for Small Oil-Fired Mechanical Draft Hot 

Water Commercial Packaged Boilers

Figure 5.5.12. Price-Efficiency Relationship for Large Oil-Fired Mechanical Draft Hot 

Water Commercial Packaged Boilers

$0

$10,000

$20,000

$30,000

$40,000

82% 84% 86% 94% 97%

Incremental Price [$]

Combustion Efficiency [%]

LGMDHW Price-Efficiency Curve

$0

$4,000

$8,000

$12,000

$16,000

$20,000

80% 85% 90% 95% 100%

Incremental Price [$]

Thermal Efficiency [%]

SOMDHW Price-Efficiency Curve

$0

$10,000

$20,000

$30,000

$40,000

$50,000

$60,000

80% 85% 90% 95% 100%

Incremental Price [$]

Combustion Efficiency [%]

LOMDHW Price-Efficiency Curve
5-18

Figure 5.5.13. Price-Efficiency Relationship for Small Gas-Fired Mechanical Draft Steam 

Commercial Packaged Boilers

Figure 5.5.14. Price-Efficiency Relationship for Large Gas-Fired Mechanical Draft Steam 

Commercial Packaged Boilers

Figure 5.5.15. Price-Efficiency Relationship for Small Oil-Fired Mechanical Draft Steam 

Commercial Packaged Boilers

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

78% 79% 80% 81% 82% 83% 84%

Incremental Price [$]

Thermal Efficiency [%]

SGMDST Price-Efficiency Curve

$0

$5,000

$10,000

$15,000

$20,000

78% 79% 80% 81% 82% 83% 84%

Incremental Price [$]

Thermal Efficiency [%]

LGMDST Price-Efficiency Curve

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

80% 81% 82% 83% 84% 85% 86% 87%

Incremental Price [$]

Thermal Efficiency [%]

SOMDST Price-Efficiency Curve
5-19

Figure 5.5.16. Price-Efficiency Relationship for Large Oil-Fired Mechanical Draft Steam 

Commercial Packaged Boilers

$0

$5,000

$10,000

$15,000

$20,000

80% 81% 82% 83% 84% 85% 86% 87%

Incremental Price [$]

Thermal Efficiency [%]

LOMDST Price-Efficiency Curve
5-20

REFERENCES

1. Directory of Certified Product Performance, Air conditioning, Heating, and Refrigeration Institute. 

(Last accessed: 11th November 2013) URL: 

https://www.ahridirectory.org/ahridirectory/pages/home.aspx