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Cyrus Nasseri

October 18, 1995

Office of Codes and Standards

Office of Building Technologies

 EE-DET-94-101 COMMENT 02

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... U.S>Departfuent ofEl1ergy 

Energy Efficiency Descriptors 

Cyrus Nasseri 

October 18, 1995 

Office of Codes and Standards 

Office of Building Technologies 

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Legislative Drivers

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• Energy Policy and Conservation Act , Public Law

94-163 (1975)

• National Energy Conservation Policy A ct, Public

Law 95-619 (1976)

• National Appliance Energy Conservation Act

(NAECA), Public Law 100-12 (1987)

• National Appliance Energy Conservation

Amendments , Public Law 100-357 (1988)

• Energy Policy Act, Public Law

102-486 (1992)

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 EE-DET-94-101 COMMENT 02

Legislative Drivers 

• Energy Policy and Conservation Act, Public Law 

94-163 (1975) 

• National Energy Conservation Policy Act, Public 

Law 95-619 (1976) 

• National Appliance Energy Conservation Act 

(NAECA), Public Law 100-12 (1987) 

• National Appliance Energy Conservation 

Amendments, Public Law 100-357 (1988) 

• Energy Policy Act, Public Law 

102-486 (1992) 
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Program Elements

• Test Procedures

• Labeling

• Standards

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 EE-DET-94-101 COMMENT 02

Program Elements 

• Test Procedures 

• Labeling 

• Standards 
Existing Energy Descriptor

Annual Fuel Utilization Efficiency (AFUE)

-Defined as the ratio of annual output energy to annual

input energy from fossil fuel, including off-season pilot

loss if used. (Does not include electricity consumption of

auxiliary equipment)

- NAECA mandated

-Isolated combustion system ( I CS) installation

- Fossil fuel energy

- Electrical energy for all electric furnaces

• Energy Factor (EF)

Not used for efficiency standards

Defined as the ratio of fossil fuel ou#put to the gum of

fossil fuel input and electrical energy input.

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 EE-DET-94-101 COMMENT 02

Existing Energy Descriptor 

• Annual Fuel Utilization Efficiency (AFUE) 

- Defined as the ratio of annual output energy to annual 

input energy from fossil fuel, including off-season pilot 

loss if used. (Does not include electricity consumption of 

auxiliary equipment) 

-- NAECA mandated 

- Isolated combustion system (ICS) installation 

- Fossil fuel energy 

- Electrical energy for all electric furnaces 

• Energy Factor (EF) 

- Not used for efficiency standard~ 

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Existing Energy Descriptor

Deficiencies

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• AFUE does not account for electricity usage by the

air circulating blower. (Furnaces could be

designed to operate the blower during the

burner-off period to extract residual amounts of

heat from the heat exchanger. This would inflate

the AFUE value , yet would actually consume more

electricity and increase the operating cost)

• AFUE does not encourage the use of more

efficient motors and controls to save energ y.

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 EE-DET-94-101 COMMENT 02

Existing Energy Descriptor 

Deficiencies 

• AFUE does not account for electricity usage by the 

air circulating blower. (Furnaces could be 

designed to operate the blower during the 

burner-off period to extract residual amounts of 

heat from the heat exchanger. This would inflate 

the AFUE value, yet would actually consume more 

electricity and increase the operating cost) 

• AFUEdoes not encourage the use of more 

eff',·"Jll ".' tr;~elv,eenergy. ' 

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 EE-DET-94-101 COMMENT 02

DOE Rulemaking 

Furnace Test Procedure 

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Notice of Proposed Rulemaking 

(NOPR) published. 

'~~~il!~~!I~~; Comment period reopened. 
Proposed Energy Descriptor

Definitions

I,

• Annual Efficiency (AE)

- Fossil fuel and auxiliary electricity

-Indoor or outdoor installation

• Energy Factor (EF)

-Fossil fuel and auxiliary electricity

-ICS installation

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 EE-DET-94-101 COMMENT 02

Proposed Energy Descriptor 

Definitions 

• Annual Efficiency (AE) 

- Fossil fuel and auxiliary electricity 

- Indoor or outdoor installation 

• Energy Factor (EF) 

-- Fossil fuel and auxiliary electricity 

- ICS installation 
Proposed Energy Descriptor

Objective

• To account for both the fossil fuel consumption

and the auxiliary electricity consumption

• To provide consumer information regarding

overall performance of the appliance (both in

terms of energy efficiency and energy cost)

with a single descriptor.

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 EE-DET-94-101 COMMENT 02

Proposed Energy Descriptor 

Objective 

• To account for both the fossil fuel consumption 

and the auxiliary electricity consumption 

• To provide consumer information regarding 

overall performance of the appliance (both in 

terms of energy efficiency and energy cost) 

with a single descriptor. 
Proposed Annual Efficiency (AE)

Descriptor

AE _ {(E Fx AFUE) + (3413 x E AE)}

{EF+(34l3xFxE A0}

E F : Annual fossil fuel consumption

EAE: Annual auxiliary electricity consumption

AFUE: Annual fuel utilization efficiency

F : Energy cost ratio, and

3,413: Conversion factor, from kWh to Btu

The numerator represents the cost to meet the heating load

without any appliance loss, with the energy price solely based

on the fossil fuel rate.

The denominator represents the total cost (fossil fuel and

auxiliary electricity). to operate the appliance.

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 EE-DET-94-101 COMMENT 02

Proposed Annual Efficiency (AE) 

Descriptor 

AE = {(E EX AFUE) + (3413 X E AE)} 

{E F + (34 1 3 x F x E A~} 

E F : Annual fossil fuel consumption 

EAE: Annual auxiliary electricity consumption 

AFUE: Annual fuel utilization efficiency 

F : Energy cost ratio, and 

3,413 : Conversion factor, from kWh to Btu 

The numerator represents the cost to meet the heating load 

without any appliance loss, with the energy price solely based 

on the fossil fuel rate . 

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Application of the Proposed

Annual Efficiency Descriptor

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• Not applied to electric furnaces or heat pumps

• Applied to fossil-fueled furnaces/boilers where

electricity consumption constitutes a small portion

(2% to 6%) of the total appliance energy

consumption

• Based upon the cost to consumers . Not an

efficiency of power generation , transmission or

source energy production .

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 EE-DET-94-101 COMMENT 02

Application of the Proposed 

Annual Efficiency Descriptor 

• Not applied to electric furnaces or heat pumps 

• Applied to fossil-fueled furnaces/boilers where 

electricity consumption constitutes a small portion 

(2% to 6%) of the total appliance energy 

consumption 

• Based upon the cost to consumers. Not an 

efficiency of power generation, transmission or 

source energy production.