20030221Comments.pdf

LISA D. NORDSTROM
DEPUTY ATTORNEY GENERAL
IDAHO PUBLIC UTILITIES COMMISSION
PO BOX 83720
BOISE, IDAHO 83720-0074
[phone]
IDAHO BAR NO. 5733
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Street Address for Express Mail:
472 W. WASHINGTON
BOISE, IDAHO 83702-5983
Attorney for the Commission Staff
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF IDAHO POWER
COMPANY'S APPLICATION FOR
AUTHORITY TO IMPLEMENT A
RESIDENTIAL AIR CONDITIONER CYCLING
PILOT PROGRAM AND TARIFF SCHEDULE81.
CASE NO. IPC-O2-
COMMENTS OF THE
COMMISSION STAFF
COMES NOW the Staff of the Idaho Public Utilities Commission, by and through its
Attorney of record, Lisa D. Nordstrom, Deputy Attorney General, and submits the following
comments in response to the Notice of Application, Notice of Modified Procedure and Notice of
Comment Deadline issued in Order No. 29176 on January 14, 2003.
BACKGROUND
On December 23 2002, Idaho Power Company filed an Application seeking authority to
institute a Residential Air Conditioner Cycling Pilot Program (AC Cycling Pilot Program or
Program) and implement proposed Tariff Schedule 81. In Idaho Power s 2002 Integrated
Resource Plan (IRP), the Company identified peak resource deficiencies facing its system in
upcoming years. To address those deficiencies, the IRP suggested targeting demand side
management (DSM) measures that reduce peak-hour demand like the Irrigation Time-of-use
(TOU) Pilot Program. The proposed Program in this Application would enable Idaho Power to
STAFF COMMENTS FEBRUARY 21 2003
begin testing the costs and benefits of reducing summer peak loads by directly controlling
residential air conditioners and/or thermostats. If properly implemented, this could potentially
decrease Idaho Power s overall energy costs, which in turn, would result in savings for all
customers.
The proposed pilot program is an optional service in which participating residential
customers would permit the Company to cycle their air conditioners or adjust their thermostats in
exchange for a programmable thermostat and a $5 monthly incentive ($15 per summer). To
monitor energy usage, Idaho Power will also install advanced time-of-use (TOU) meters at
participants' residences, but without TOU rates. The two-year dispatchable load control program
will expire on September 30, 2004 unless extended by the Company. Idaho Power will restrict
Program participation to 200 customers in the first year and 300 additional customers in the
second year. The Company will initiate AC cycling for up to four hours per day between 1 p.
and 9 p., 10 weekdays per summer month, by sending a signal to the programmable
thermostat. The signal would instruct it to:
cycle the AC compressor for a specified length of time on a percentage basis, or
cycle the AC compressor until a specified temperature change is attained, or
change the temperature set-point on the thermostat for a specified length oftime.
While all three of the above options are listed in the proposed tariff, the Company has
indicated to Staff that it may later choose just one of the options to test and evaluate.
STAFF COMMENTS
Evaluate All Options
Staff generally supports the Company s Application as a method to achieve peak-hour
demand reductions. This proposed program directly responds to the Commission s directive for
the Company to "
...
give balanced consideration to demand side and supply side resources when
formulating resource plans and when procuring resources.2 In that spirit, Staff recommends that
the Company implement and evaluate more than one of the AC cycling options that are listed
above and offered in the proposed tariff. In particular, Staff prefers having the temperature set-
point method included in the pilot. Staff believes that cycling the compressor will have much the
1 Idaho Power Response to Staff Production Request No. 4(b)2 Order No. 22299, Case No. U-1500-165, p 20 and Order No. 29189, case No. IPC-02-, p. 20
STAFF COMMENTS FEBRUARY 21 2003
same effect as adjusting the thermostat to a higher set-point, but that it may result in too high
temperatures for some participants. Obviously, the effectiveness of changing the thermostat's
temperature set-point for a specified length oftime cannot be compared to the effectiveness of
the two compressor cycling methods unless all three options are tested.
According to the Company s presentation to its Energy Efficiency Advisory Group
(EEAG) on November 14, 2002, cycling AC compressors for a specified length oftime will
result in a maximum temperature increase of two degrees for most customers. Notwithstanding
this relatively small ma~imum increase for most customers, Staff notes that cycling the
compressor will result in a wider range of temperatures among all participating households than
would occur with thermostat adjustments. For example, a few customers with undersized AC
units, faulty ducts, poor building envelopes, or large, west-facing windows will likely experience
higher temperatures that may not be acceptable when their compressors are cycled for a specified
length of time. The option of adjusting the thermostat set-point by two degrees would limit the
range of temperature effects and may increase customer satisfaction with the Program. In any
case, Staff believes that the value of the pilot program is greatly reduced if all the options are not
tested. As explained later in these Comments, we believe the proposed $810 220 budget should
be sufficient to test and evaluate more than a single AC cycling option.
Emergency Situations
Although Staff has no reason to dispute the Company s assertion that compressor cycling
will result in a maximum indoor temperature increases of only two degrees for most customers
we are concerned about those few customers whose indoor temperatures may increase much
more due to their particular circumstances or an unusual, perhaps emergency, situation. When
this concern was expressed at its EEAG meeting, the Company s initial response was that those
customers should not volunteer for the program or that they will be able to notify the Company
the day before they expect to experience the unusual situation. Later, in response to Staff
Production Request No 8(b), the Company said that in rare cases of emergency it "
...
will work
with the customer on a case-by-case basis to reach a mutually satisfactory outcome." Although
Staff is not certain what this will entail, we trust that the Company will treat its volunteer
customers in a reasonable and fair manner.
STAFF COMMENTS FEBRUARY 21 , 2003
Effects on Compressor Life
Staff is concerned about the possible detrimental effect of cycling air conditioners on the
life of the compressor. The Company dismisses this concern based on: 1) consultation with
purveyors of thermostats and load control equipment; 2) consultation with managers of AC
cycling programs at other utilities, and 3) AC cycling parameters published by the Air
Conditioning & Refrigeration Institute (ARI).3 Staff notes that ART's Guideline A cautions that
the effect of (load control) devices on equipment warranties may vary product-by-product" and
therefore
, "...
that equipment manufacturers be contacted for specific recommendations.
(emphasis added) ART's Guideline A also states that it does not guarantee that any tests
conducted under its standards will be non-hazardous or free from risk. (See Attachment A)
Staff appreciates that Idaho Power has conducted research regarding possible detrimental effects
of its proposed program, but we do not believe that it presents conclusive evidence that there are
no detrimental effects. Instead, we believe this research shows that the detrimental effects will
likely be relatively small for most participants and that they are unlikely to result in air
conditioners failing during their warranty periods. Staff is more concerned about air conditioners
that are older than their warranty periods because these are the ones that are most apt to fail and
whose owners may believe that Idaho Power s cycling of the compressors caused or contributed
to the failure.
Although Idaho Power acknowledges a report (Attachment B) by the United States
Department of Energy (DOE) indicating that frequent cycling of air conditioners reduces
efficiency and wears out the compressor and electrical parts more rapidly,4 the Company
dismisses the reported detrimental effects because DOE's purpose was to report the effects of
over-sizing rather than utility-controlled cycling.s Staff believes that the adverse effects of
frequent cycling are not dependent upon the cause of the frequent cycling as suggested by Idaho
Power. The detrimental mechanical and electrical effects of frequent cycling occur whether such
cycling is caused by an over-sized unit or by a utility controlling it. While Staff believes the
potential incremental 6 effects from the Program may be small due to the limited hours of cycling
proposed, we cannot simply dismiss the likelihood that some of Idaho Power s proposed
3 Idaho Power Response to Staff Production Request No.
4 Energy Efficient Air Conditionir1g, DOE/GO-10099-379, FS 206, June 1999, p. 55 Idaho Power Response to Staff Production Request No.
6 Staff also believes air conditioners are often over-sized and thus already cycle on and off frequently. The Program
may not significantly increase the cycling frequency of these air conditioners.
STAFF COMMENTS FEBRUARY 21 2003
program options will accelerate wear on air conditioners--especially AC units that are sized
correctly, i.e. sized to run at optimum efficiency rather than sized to compensate for inadequate
building envelopes and/or poor ductwork. Staff believes the option of adjusting the thermostat'
temperature set-point will not have this effect because it will not cause compressors to cycle
more frequently. In conclusion, we believe that it would be prudent for Idaho Power to advise its
Program participants of DOE's findings regarding the detrimental effects of frequent cycling on
compressor longevity and efficiency, and the reasons why the Company does not believe that
this should cause concern. Staff suggests that the Company provide each participant a copy of
the DOE Energy Efficient Air Conditioning report and ARI Guideline A. (Attachments A and B)
Evaluate Effects of Advanced Thermostat
As part of this program, Idaho Power will install advanced, programmable thermostats in
the homes of participants that customers will be able to program and adjust from remote
locations via the Internet. Clearly these advanced thermostats, by themselves, will provide the
opportunity and perhaps incentive for participants to change their electricity consumption
patterns. In fact, the Company suggested to the EEAG that the thermostats would enable
participants to reduce their energy costs and stated that the thermostats "may reduce overall
energy use.? However, the Company does not intend to evaluate the thermostats' effects on
either energy consumption or demand, and will instead focus only on the effects of the AC
cycling.8 By not assessing the effects of the advanced thermostats, Staff believes the Company
will miss not only the opportunity to evaluate the effects of such thermostats, but that it will be
unable to isolate the effects of the thermostats from the AC cycling effects. Staff believes that
assessing the effects of the programmable thermostats is important and could be achieved
through the analysis of the load profiles of customers in a control group. Staff suggests that this
control group (i., households whose air conditioners and thermostats are not controlled by the
Company) should include customers who get a programmable thermostat in addition to a TOU
meter. However, for reasons explained below, we suggest that another control group should
include customers who only get a TOU meter and are not told that they are part of a control
group for this pilot program.
7 Application at 2
8 Idaho Power Response to Staff Production Request No. 4(a)
STAFF COMMENTS FEBRUARY 21 , 2003
Need for Pilot Program
Air conditioning cycling and other residential direct load control programs (e.g. water
heaters) have been used successfully by hundreds of other electricity utilities for many years.
Idaho Power states that it wants to assess the feasibility, practicality, cost-effectiveness and
customer satisfaction of this type of dispatchable program given the geographic and climate
characteristics of its service area.lO Staff agrees that the climate, housing, topographic and
demographic characteristics in Idaho Power s service area combined with its relatively low
electricity rates warrant a pilot program. However, to' properly evaluate this pilot, generally
accepted program evaluation methods prefer use of a control group to provide a more accurate
basis for statistical comparisons. Staff is concerned that Idaho Power does not plan to include a
control group in its evaluation. Instead, the Company said that program effectiveness "will be
evaluated by comparing average load profiles of the participants on cycling days with the
average load profiles of the participants on similar non-cycling days.ll Staff notes that days
with similar cooling degree days are not necessarily similar in other important ways, such as
cloud cover, humidity, wind speed and direction, hours of daylight and solar angle and intensity.
A control group would help explain the variability between so-called similar days. Furthermore
a control group will help determine the extent to which the volunteers' electricity usage is
influenced by the fact that they are part of a test.
Additional Air Conditioning Program Options
Staff believes that air conditioner programs focusing on the proper sizing of AC units
adequate return air flow, proper charging, clean coils, properly sealed ducts, and well-insulated
and sealed building envelopes may offer additional opportunities to reduce summer peak loads.
It would be prudent for the Company to measure and evaluate these variables, together with the
interactive effects with the proposed AC Cycling, as part of this Program. In its response to Staff
Production Request No. 5(b), the Company agreed that the AC cycling program may
complement other programs designed to correct air conditioning inefficiencies. While the
9 Impact of Direct Load Control Programs: A Duty-Cycle Approach, EPRI Report CU-7028-, 1991 , Abstract
10 Idaho Power Response to Staff Production Request No. 5(b)
11 Idaho Power Response to Staff Production Request No. 4(b) and (c)12 As previously discussed, isolation of the effects of installing advanced programmable thermostats requires its own
control group.
STAFF COMMENTS FEBRUARY 21 , 2003
addition of an AC maintenance control group would expand the scope of the pilot program
proposed by the Company, this is an opportune time to evaluate programs that affect air
conditioners.
An additional AC program the Company and its EEAG should consider is one that would
encourage the use of evaporative coolers instead of air conditioners. DOE reports that
evaporative coolers are suitable for areas with low humidity, cost about one-half as much as air
conditioners, and use about one-fourth the energy required by air conditioners.
Importance of Reporting
As previously stated, the Company s choice of a pilot program is appropriate because of
the particular characteristics of its rates and service area. In discussion ofldaho Power
irrigation pilot program in its 2002 IRP the Company recognized:
The purpose of the Pilot Program is to gather meaningful information regarding
irrigation customers' ability to shift energy consumption from higher-cost peak
hours to lower-cost off-peak periods. The data collected during the pilot program
is expected to provide Idaho Power Company, the customers of Idaho Power, and
the Idaho PUC with the information necessary to evaluate the impacts, costs, and
benefits of time-of-use pricing.
Although information gathering is the primary goal of a pilot program, Staff notes that it has still
not received a full report for the Company s 1999 Idaho City automated meter reading trial.
Absent a report containing detailed evaluation of the effects of the proposed AC cycling options
and a comparison to appropriate control groups, the Commission may have difficulty finding that
the costs of this pilot program were prudently incurred given that the program did not meet its
informational objectives.
Costs of Customer Incentives and Program Promotion and Recruitment
The Company s estimated $810 220 budget for this 2-year pilot program contains
$200 000 for promotion and an additional, unspecified amount for recruitment, but allocates only
$10 500 for customer incentives. (See Attachment C)l4 Staff believes that tripling of the budget
for customer incentives (i., $15 per month instead of $5 per month) would reduce the budget
13 Idaho Power Company 2002 Integrated Resource Plan, page 47.
14 Attachment C, lines 15, 16 and 18 of the Estimated Costs thatIdaho Power provided in response to Staff
Production Request No.
STAFF COMMENTS FEBRUARY 21 2003
requirements for recruitment and promotion to a more reasonable level. If the Company were to
spend an additional $21 000 on incentives to make the program more attractive to customers, it
would likely save a couple hundred thousand dollars on promotion and recruitment. Some of the
savings from reduced promotion and recruitment costs could be spent on monitoring control
groups and more comprehensive program evaluation. At the November 14 2002 EEAG
meeting, the Company estimated that by not paying an incentive to participants and assuming
000 ultimate participants, the levelized cost of system-wide AC cycling program equates to
$54 per kilowatt of capacity. By paying a $5 monthly incentive ($15 per summer) to
participants, the Company estimated the levelized cost of AC cycling increases to $69 per
kilowatt. Accordingly, Staff estimates that by paying participants $15 per month ($45 per
summer) the levelized cost will increase to $99 per kilowatt. At the same EEAG meeting, Idaho
Power said that the Program s relatively low cost per kilowatt of capacity compares favorably to
the $600 to $800 per kilowatt capacity of a gas-fired peaker combustion turbine.
STAFF CONCLUSIONS AND RECOMMENDATIONS
While the Company acknowledges the importance of data collection in order to evaluate
the Program, it appears that Idaho Power may not evaluate all the available options or compare
the demand of Program participants to any control groups. It is essential that this pilot program
include adequate data collection, evaluation and reporting of all options as well as distinguish the
effects of these options from the effects of the advanced thermostat. Specifically, Staff believes
that all three options listed in the Company s proposed tariff (i., cycling the AC unit for a
specified length of time, cycling the AC unit until specified temperature change is attained, and
changing the temperature set point) should be tested and evaluated. If the Company believes it
can implement and evaluate only one of those options, Staff believes the thermostat adjustment
is the best single option.
Staff also believes that monitoring the energy use of two control groups, one with the
advanced thermostats and one without, would provide valuable data necessary to evaluate the
success of this program. Furthermore, we believe summer peak and overall energy use can be
reduced by promoting proper sizing, installation and maintenance of air conditioners and ducts
and perhaps by promoting evaporative coolers. Utilizing all three AC cycling options, two
control groups, plus an AC maintenance control group would provide a full spectrum of data and
STAFF COMMENTS FEBRUARY 21 , 2003
allow the Company and the Commission to determine which AC program variation is the most
energy efficient and acceptable to customers.
In conclusion, Staff supports the Company s proposal with the suggestions offered above.
Respectively submitted this
sf-
c2 rday of February 2003.
Lisa D. Nordstrom
Deputy Attorney General
Technical Staff: Dave Schunke
Lynn Anderson
LN :i:umisc/commentslipceO2. 1 31ndesJa
STAFF COMMENTS FEBRUARY 21 2003
1987
GUIDELINE for
(REAFFIRMED 1997)
~ IJ
~' .--,-
AIR-CONDITIONING &
REFRIGERATION
INSTITUTE
ENERGY
MANAGEMENT
SYSTEMS AND
LOAD
MANAGEMENT
THROUGH
DUTY
LIN
Guideline
Attachment A
Case No. IPC-02-
Staff Comments
02/21/03 Page 1 of 3
4301 NORTH FAIRFAX DRIVE ARLINGTON. VIRGINIA 22203
IMPORT ANT
SAFETY RECOMMENDA nONS
It is strongly recommended that the product be designed, constructed, assembled and installed in accordance
with nationally recognized safety requirements appropriate for products covered by this guideline.
ARI, as a manufacturers' trade association, uses its best efforts to develop guidelines employing state-of-the-
art and accepted industry practices. However, ARI does not certify or guarantee safety of any products
components or systems designed, tested, rated, installed or operated in accordance with these guidelines or
that any tests conducted under its standards will be non-hazardous or free from risk.
Note:
This is a new guideline.
(Reaffirmed 1997)
Attachment A
Case No. IPC-02-
Staff Comments
02/21/03 Page 2
Price $S.OO (M) $10.00 (NM)
Printed in U.
~~...
-do(l \OCopyright 1987, by Air-Conditioning and Refrigeration Institute
Remstered United States Patent and Trademark Office
ARI GUIDELINE A-1987
ARI GENERAL GUIDELINES ON ENERGY MANAGEMENT
SYSTEMS AND LOAD MANAGEMENT THROUGH DUTY
CYCLING
ARI recognizes the desire of many customers, users and
other building owners to install some sort of energy
management system (EMS) device on heating, ventilating,
air conditioning and refrigeration equipment. It is also
recognized that some power suppliers feel the need to effect
load management through duty cycling," a program
designed to reduce the peak load on a power distribution
system and hence delay or eliminate the need for additional
generating capacity. ARI offers these guidelines without
stipulating that either energy savings, user comfort or
equipment performance will be achieved.
The product scope of ARI encompasses a wide variety of
products. The availability of various type of EMS devices is
very broad and the effect of such devices on equipment
warranties may vary product-by-product and manufacturer-
to-manufacturer. Therefore, ARI urges that the equipment
manufacturer be contacted for specific recommendations
concerning that equipment.
The general guidelines are as follows:
1. Safety
Do not alter, disable or bypass any of the safety
controls.
2. Control Circuits
Control the unit operation through the control
wiring. An auxiliary power supply may be required
to carry the load of any additional field supplied
controls. Additional load on the equipment
transformer can cause voltage drop, chattering
contactors, and ultimate failure of motor-
compressor or other components.
3. Fail-Safe Requirement
In the event of failure of an add-on control
device(s), the normal operation of the equipment
being controlled should not be jeopardized.
4. Cycle Rate
Do not short cycle motor controllers, motors, or
motor-compressors. The compressor off cycle must
be five (5) minutes or longer. If more than four (4)
cycles per hour are anticipated, contact the
equipment manufacturer for specific
recommendations.
5. Fossil Fuel Heating Equipment
Do not short cycle or underfire fossil fuel heating
equipment. Adequate burner operating time and
temperature is necessary to prevent condensation
damage to heat exchanger and/or flue.
In the event of any conflict between the manufacturers
specific instructions and these Guidelines, such instructions
should prevail over these Guidelines.
The information in these Guidelines is current as of the date
of publication. These Guidelines are only guidelines and
should not be referred to or construed as a standard,
certification or warranty. The appropriate steps to be taken
with respect to duty cycling devices should be done by and
under the supervision of qualified and experienced personnel
to insure proper installation, and should be properly
inspected. However, no changes in these Guidelines (when
identified as ARI guidelines) shall be made without the
approval of ARI.
Released for publication by the ARI General Standards
Committee on June 12, 1985.
Note: Published in the approved ARl Guideline Format in
1987 without change.
Attachment A
Case No. IPC-02-
Staff Comments
02/21/03 Page 3 on
ENERGY
EFFICIENCY
AND
RENEWABLE
DOE/GO-IOO99-379
FS 206
June 1999
Energy-Efficient
Air Conditioning
Are you considering buying a new air
conditioner? Or. are you dissatisfied with
the operation of your current air condi-
tioner? Are you unsure whether to fix or
replace it? Are you concerned about high
summer utility bills? If you answered yes
to any of these questions, this publication
can help. With it, you can learn about
various types of air conditioning systems
and how to maintain your air conditioner,
hire professional air conditioning services,
select a new air conditioner, and ensure
that your new air conditioner is properly
installed.
This publication discusses both central
and room air conditioners. Heat pumps,
which provide both home cooling and
heating, are not covered in this publica-
tion. Contact the Energy Efficiency and
Renewable Energy Clearinghouse
(EREC-see Source List below) for more
information about heat pumps of all kinds.
How Air Conditioners Work
Understanding Air Conditioners
Air conditioners employ the same operat-
ing principles and basic components as
your home refrigerator. An air conditioner
cools your home with a cold indoor coil
called the evaporator. The condenser, a hot
outdoor coil, releases the collected heat
outside. The evaporator and condenser
coils are serpentine tubing surrounded by
aluminum fins. This tubing is usually
made of copper. A pump, called the
compressor, moves a heat transfer fluid
(or refrigerant) between the evaporator
and the condenser. The pump forces the
Many people buy or use air conditioners
without understanding their designs,
components, and operating principles.
Proper sizing, selection, installation,
maintenance, and correct use are keys to
cost-effective operation and lower overall
costs.
Air Conditioning
, \- \
;1'Condenser coil
The fluid that collects heat at the evaporator and releases it at the condenser is called refrigerant.
A pump, called the compressor, forces the refrigerant through the circuit of tubing and rms in
the coils. Air moves through the tiny spaces between the fins and is cooled by the refrigerant inthe coils.
This document was produced for the US. Department of Energy (DOE) by the National Renewable Energy Laboratory (NREL). DOE national laboratory.
The document was produced by the Information Services Program, under the DOE Office of Energy Efficiency and Renewable Energy. The Energy Efficiency
and Renewable Energy Clearinghouse (EREC) is operated by NCI Information Systems. Inc., for NREL/ DOE, The statements contained herein arc based
information known to EREC and NREL at the time of printing. No recommendation or endorsement of any product or service is implied if mentioned by EREC.
Printed with a renewable-source Ink on paper containing at least 50% wastepaper. including 20% postconsumer waste \.;t
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 1 of7
refrigerant through the circuit of tubing
and fins in the coils. The liquid refrigerant
evaporates in the indoor evaporator coil,
pulling heat out of indoor air and thereby
cooling the home. The hot refrigerant gas
is pumped outdoors into the condenser
where it reverts back to a liquid giving up
its heat to the air flowing over the
condenser s metal tubing and fins.
Types of Air Conditioners
The basic types of air conditioners are
room air conditioners. split-system central
air conditioners, and packaged central air
conditioners.
Room Air Conditioners
Room air conditioners cool rooms rather
than the entire home. If they provide cool-
ing only where they re needed, room air
conditioners are less expensive to operate
than central units, even though their
efficiency is generally lower than that of
central air conditioners.
Smaller room air conditioners (Le., those
drawing less than 1.5 amps of electricity)
can be plugged into any 15- or 20-amp,
lIS-volt household circuit that is not
shared with any other major appliances.
Larger room air conditioners (Le., those
drawing more than 1.5 amps) need their
own dedicated lIS-volt circuit. The
largest models require a dedicated
230-volt circuit.
Condenser fan
Evaporator fan
Room Air Conditioner
Room air conditioners are installed directly in ,Windows or walls, which means
they have no ductwork. The evaporator s fan faces indoors, while the condenser
fan faces outdoors.
Central Air Conditioners
Central air conditioners circulate cool air
through a system of supply and return
ducts. Supply ducts and registers (i.e.,
openings in the walls, floors, or ceilings
covered by grills) carry cooled air from the
air conditioner to the home. This cooled
air becomes warmer as it circulates
through the home; then it flows back
to the central air conditioner through
return ducts and registers. A central air
conditioner is either a split"system unit or
a packaged unit.
hi a split-system central air conditioner,
an outdoor metal cabinet contains the
condenser and compressor, and an indoor
cabinet contains the evaporator. In many
split -system air conditioners, this indoor
cabinet also contains a furnace or the
indoor part of a heat pump. The air
conditioner s evaporator coil is installed
in the cabinet or main supply duct of this
furnace or heat pump. If your home
already has a furnace but no air
conditioner, a split-system is the most
economical central air conditioner to install.
In a packaged central air conditioner, the
evaporator, condenser, and compressor
are all located in one cabinet, which
usually is placed on a roof or on a concrete
slab next to the house s foundation. This
type of air conditioner also is used in
small commercial buildings. Air supply
and return ducts come from indoors
through the ho ' s exterior wall or roof to
connect with the packaged air conditioner
which is usually located outdoors. Pack-
aged air conditioners often include electric
heating coils or a natural gas furnace. This
combination of air conditioner and central
heater eliminates the need for a separate
furnace indoors.
-';
Maintaining Existing
Air Conditioners'
Older air conditioners may still be able to
offer years of relatively efficient use.
However, making your older air condi-
tioner last requires you to perform proper
operation and maintenance.
Attachment B
Case No. IPC-O2-
Staff Comments
02/21/03 Page 2 of7
Packaged Air Conditioner
Evaporator
A packaged air conditioner sits outside the house next to the foundation or on the
roof. Its cabinet contains the evaporator, condenser, compressor, and all other parts
of the air conditioner. Supply and return ducts connect to this outdoor cabinet.
Evaporative Coolers
An evaporative cooler (also called a "swamp cooler ) is a completely different
type of air conditioner that works well in hot, dry climates.
Evaporative Cooler
1\,.!2'
;;;:
Evaporative coolers cost about half as much as central air conditioners and
use about"25% less energy.75'-
TheseW1its cool outdoor air by evaporation and blow it inside the building,
causing a cooling effect much like the process when evaporating perspiration
co01s your body on a hot (but not overly humid) day. When operating an
evaporative cooler, windows are opened part way to allow warm indoor air
to escape as it is replaced by cooled air.
Evaporative coolers cost about one-half as much to install as central air condi-
tioners and use about one- uarter as much ener . However. they require
more frequent maintenance an re rigerate air conditioners and they
suitable only for areas with low humidity.
Air Conditioning Problems
One of the most common air conditioning
problems is improper operation. If your air
conditioner is on, be sure to close your
home s windows and outside doors. '
;;;:
Other common problems with existing air
conditioners result from faulty installation,
poor service procedures, and inadequate
maintenance. Improper installation of your
air conditioner can result in leaky ducts
and low air flow. Many times, the refriger-
ant charge (the amount of refrigerant in the
system) does not match the manufacturer
specifications. If proper refrigerant charging
is not performed during installation, the
performance and efficiency of the unit is
impaired. Service technicians often fail to
find refrigerant charging problems or even
worsen existing problems by adding refrig-
erant to a system that is already full. Air
conditioner manufacturers generally make
rugged. high quality products. If your air
conditioner fails, it is usually for one of the
common reasons listed below:
refrigerant leaks. If your air conditioner
is low on refrigerant, either it was
undercharged at installation, or it leaks.
If it leaks, simply adding refrigerant is
not a solution. A trained technician
should fix any leak, test the repair, and
then charge the system with the correct
amount of refrigerant. Remember that
the performance and efficiency of your.
air conditioner is greatest when the
refrigerant charge exactly matches the
manufacturer s specification, and is
neither undercharged nor overcharged.
inadequate maintenance. If you allow
filters and air conditioning coils to
become dirty, the air conditioner will
not work properly, and the compressor
or fans are likely to fail prematurely.
electric control failure. The compressor
and fan controls can wear out, especially
when the air conditioner turns on and
off frequently, as is common when a
system is oversized. Because corrosion
of wire and terminals is also a problem
in many systems, electrical connections
and contacts should be checked during
a professional service call.
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 3 of7
The most important
maintenance task
that will ensure the
efficiency of your air
conditioner is to
routinely replace
clean its fUters.
Regular Maintenance
An air conditioner s filters, coils, and fins
require regular maintenance for the unit to
function effectively and efficiently
throughout its years of service. Neglecting
necessary maintenance ensures a steady
decline in air conditioning performance
while energy use steqdily increases.
Air Conditioner Filters
The most important maintenance task that
will ensure the efficiency of your air con-
ditioner is to routinely replace or clean its
filters. Clogged, dirty filters block normal
air flow and reduce a system s efficiency
significantly. With normal air flow obstructed,
air that bypasses the filter may carry dirt
directly into the evaporator coil and
impair the coil's heat-absorbing capacity.
Filters are located somewhere along the
return duct s length. Common filter
locations are in walls, ceilings, furnaces, or
in the air conditioner itself.
Some types of filters are reusable; others
must be replaced. They are available in a
variety of types and efficiencies. Clean or
replace your air conditioning system s filter
or filters every month or two during the
cooling season. Filters may need more
frequent attention ifthe air conditioner is
in constant use, is subjected to dusty
conditions, or you have fur-bearing pets
in the house.
Air Conditioner Coils
The air conditioner s evaporator coil and
condenser coil collect dirt over their
months and years of service. A clean filter
prevents the evaporator coil from soiling
quickly. In time, however, the evaporator
coil will still collect dirt. This dirt reduces
air flow and insulates the coil which
Leakage at registers
reduces its ability to absorb heat.
Therefore, your evaporator coil should be
checked every year and cleaned as
necessary.
Outdoor condenser coils can also become
very dirty if the outdoor environment is
dusty or if there is foliage nearby. You can
easily see the condenser coil and notice if
dirt is collecting on its fins.
You should minimize dirt and debris near
the condenser unit. Your dryer vents,
falling leaves, and lawn mower are all
potential sources of dirt and debris.
Cleaning the area around the coil, removing
any debris, and trimming foliage back at
least 2 feet (0.6 meters) allow for adequate
air flow around the condenser.
Coil Fins
The aluminum fins on evaporator and
condenser coils are easily bent and can
block air flow through the coil. Air
conditioning wholesalers sell a tool called
a "fin comb" that will comb these fins
back into nearly original condition.
Sealing and Insulating Air Ducts
An enormous waste of energy occurs
when cooled air escapes from supply
ducts or when hot attic air leaks into
return ducts. Recent studies indicate that
10% to 30% ofthe conditioned air in an
average central air conditioning system
escapes from the ducts.
For central air conditioning to be efficient,
ducts must be airtight. Hiring a competent
professional service technician to detect
and correct duct leaks is a good investment
since leaky ducts may be difficult to find
without experience and test equipment.
Duct Leakage at Seams and Registers
,::
Air from hot attics can leak into the home around registers of the duct system. Air in the ducts
can leak out through holes and seams.
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 4 of 7
Ducts must be sealed with duct "mastic.
The old standby of duct tape is ineffective
for sealing ducts.
Obstructions can impair the efficiency of a
duct system almost as much as leaks. You
should be careful not to obstruct the flow
of air from supply or return registers with
furniture, drapes, or tightly fitted interior
doors. Dirty filters and clogged evaporator
coils can also be major obstructions to air
flow.
The large temperature difference between
attics and ducts makes heat conduction
through ducts almost as big a problem as
air leakage and obstructions. Ducts in
attics should be insulated heavily in
addition to being made airtight.
Using Your Air Conditioner
An air conditioner will cool the air in your home fairly quickly. For economical
operation, turn it on only when your home is occupied. You may consider
installing a programmable thermostat. These aJlow you to set the time when
the air conditioner wiIJ turn on, such as 30 minutes before you arrive home
from work on a hot day. Contact EREC (see Source List) for the fact sheet
Automatic and Programmable Thennostats. During the day, keep the drapes or
blinds closed on windows that face east, south, and west. This will help reduce
solar heat gain into your home.
Buying New Air Conditioners
Today s best air conditioners use 30% to 50%
less energy to produce the same amount
of cooling as air conditioners made in the
mid 1970s. Even if your air conditioner is
only 10 years old, you may save 20% to 40%
of your cooling energy costs by replacing
it with a newer. more efficient model.
Sizing Air Conditioners
Air conditioners are rated by the nurn,ber
of British Thermal Units (Btu) of heat they
can remove per hour. Another common
rating term for air conditioning size is the
ton " which is 12 000 Btu per hour.
How big should your air conditioner be?
The size of an air conditioner depends on:
. how large your home is and how many
windows it has;
. how much shade is on your home
windows. walls, and roof;
. how much insulation is in your home
ceiling and walls;
. how much air leaks into your home
from the outside; and
. how much heat the occupants and
appliances in your home generate.
An air conditioner s efficiency, performance,
durability, and initial cost depend on
matching its size to the above factors.
Make sure you buy the correct size of air
conditioner. Two groups-the Air Condi-
tioning Contractors of America (ACCA)
and the American Society of Heating,
Refrigerating, and Air Conditioning
Engineers (ASHRAE)-publish calculation
procedures for sizing central air condition-
ers. Reputable air conditioning contractors
will use one of these procedures, often
performed with the aid of a computer, to
size your new central air conditioner.
Be aware that a large air conditioner will
not provide the best cooling. Buying an
oversized air conditioner penalizes you in
the following ways.
. It costs more to buy a larger air
conditioner than you need.
. The larger-than-necessary air condi-
tioner cycles on and off more frequently,
reducing its efficiency. Frequent cycling
makes indoor temperatures fluctuate
more and results in a less comfortable
environment. Frequent cycling also
inhibits moisture removal. In humid
climates, removing moisture is essential
for acceptable comfort. In addition, this
cycling wears out the compressor and
electrical parts more rapidly.
. A larger air conditioner uses more
electricity and creates added demands
on electrical generation and delivery
systems.
Air Conditioner Efficiency
Each air conditioner has an energy-
efficiency rating that lists how many Btu
per hour are removed for each watt of
power it draws. For room air conditioners,
this efficiency rating is the Energy
Efficiency Ratio, or EER. For central air
conditioners, it is the Seasonal Energy
Efficiency Ratio, or SEER.. These ratings
are posted on an Energy Guide Label
which must be conspicuously attached to
all new air conditioners. Many air condi-
tioner manufacturers are participants in
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 5 on
. ~, -
The higher
initial cost of
energy-efficient
model will be repaid
to you several times
during its life span.
the voluntary EnergyStarCID labeling
program (see Source List in this publication).
EnergyStar-labeled appliances mean that
they have high EER and SEER ratings.
In general, new air conditioners with
higher EERs or SEERs sport higher price
tags. However, the higher initial cost of an
energy-efficient model will be repaid to
you several times during its life span.
Your utility company may encourage the
purchase of a more efficient air conditioner
by rebating some or all of the price
difference. Buy the most efficient air
conditioner you can afford, especially if
you use (or think you will use) an air
conditioner frequently and/or if your
electricity rates are high.
Room Air Conditioners-EER
Room air conditioners generally range
from 5,500 Btu per hour to 14.000 Btu per
hour. National appliance standards
require room air conditioners built after
January I, 1990, to have an EER of 8.0 or
greater. Select a room air conditioner with
an EER of at least 9.0 if you live in a mild
climate. If you live in a hot climate, select
one with an EER over 10.
The Association of Home Appliance
Manufacturers reports that the average
EER of room air conditioners rose 47%
from 1972 to 1991. If you own a 1970s-
vintage room air conditioner with an
EER of 5 and you replace it with a new
one with an EER of 10, you will cut your
air conditioning energy costs in half.
Central Air Conditioners-SEER
, National minimum standards for central
air conditioners require a SEER of 9.7 and
10., for single-package and split-systems,
respectively. But you do not need to settle
for the minimum standard-there is a wide
selection of units with SEERs reaching
nearly 17.
Before 1979 , the SEERs of central air con-
ditioners ranged from 4.5 to 8.0. Replacing
a 1970s-era central air conditioner with
a SEER of 6 with a new unit having a
SEER of 12 will cut your air conditioning
costs in half.
Hiring Professional Service
When your air conditioner needs more
than the regular maintenance described
previously, hire a professional service
technician. A well-trained technician will
find and fix problems in your air condi-
tioning system. However, not all service
technicians are competent. Incompetent
service technicians forsake proper
diagnosis and perform only minimal stop-
gap measures. Insist that the technician:
. check for correct amount of refrigerant;
. test for refrigerant leaks using a leak
detector;
. capture any refrigerant that must be
, evacuated from the system, instead of
illegally releasing it to the atmosphere;
. check for and seal duct leakage in
central systems;
. measure air flow through the evaporator
coil;
. verify the correct electric control
sequence and make sure that the heating
system and cooling system cannot
operate simultaneously;
. inspect electric terminals, clean and
tighten connections, and apply a non-
conductive coating if necessary;
. oil motors and check belts for tightness
and wear; and
. check the accuracy of the thermostat.
Choosing a Contractor
Choosing a contractor may be the most
important and difficult task in buying a
ne"v central air conditioning system. Ask
prospective contractors for recent references.
If you are replacing your central air
conditioner, tell your contractor what you
liked and did not like about the old
system. If the system failed. ask the
contractor to find out why. The best time
to fix existing problems is when a new
system is being installed.
When designing your new air conditioning
system, the contractor you choose should:
. use a computer program or written
calculation procedure to size the air
conditioner;
. provide a written contract listing the
main points of your installation that
includes the results of the cooling load
calculation;
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 6 of 7
.. ; , .
. give you a written warranty on equip-
ment and workmanship; and
. allow you to hold the final payment
until you are satisfied with the new
system.
Avoid making your decision solely on
the basis of price. The quality of the
installation should be your highest
priority. because quality will determine
energy cost, comfort, and durability.
Installation and Location of
Air Conditioners
If your air conditioner is installed
correctly. or if major installation problems
are found and fixed, it will perform
efficiently for years with only minor
routine maintenance. However, many
air conditioners are not installed correctly.
As an unfortunate result, modern energy-
efficient air conditioners can perform
almost as poorly as older inefficient models.
Be sure that your contractor performs the
following procedures when installing a
new central air conditioning system:
. allows adequate indoor space for the
installation. maintenance. and repair of
the new system. and installs an access
door in the furnace or duct to provide a
way to clean the evaporator coil.
. uses a duct-sizing methodology such as
the Air Conditioning Contractors of
America (ACCA) Manual
. ensures there are enough supply
registers to deliver cool air and enough
return air registers to carry warm house
air back to the air conditioner.
. installs duct work within the conditioned
space. not in the attic, wherever possible.
. seals all ducts with duct mastic and
heavily insulates attic ducts.
. locates the condensing unit where its
noise will not keep you or your
neighbors awake at night, if possible.
. places the condensing unit in a shady
spot, if possible, which can reduce your
air conditioning costs by 1 % to 2%.
. verifies that the newly installed air
conditioner has the exact refrigerant
charge and air flow rate specified by the
manufacturer.
. locates the thermostat away from heat
sources, such as windows, or supply
registers.
Insulating Ducts
All ducts should be insulated when they are
located in attics or crawl spaces.
Sealing Ducts
Reputable contractors seal alljoints in \,)oth
new and existing ducts with duct mastic.
If you are replacing an older or failed split
system. be sure that the evaporator coil is
replaced with a new one that exactly
matches the condenser coil in the new
condensing unit. (The air conditioner
efficiency will likely not improve if the
existing evaporator coil is left in place;
in fact. the old coil could cause the new
compressor to fail prematurely.
If you install a new room air conditioner
try to:
. locate the air conditioner in a window
or wall area near the center of the room
and on the shadiest side of the house.
. minimize air leakage by fitting the room
air conditioner snugly into its opening
and sealing gaps with a foam weather
stripping material.
Paying attention to your air conditioning
system saves you money and reduces
environmental pollution. Notice whether
your existing system is running properly,
and maintain it regularly. Or, if you need
to purchase a new air conditioner, be sure
it is sized and installed correctly and has a
good EER or SEER rating.
ffi
;;:
Attachment B
Case No. IPC-02-
Staff Comments
02/21/03 Page 6 of7
Idaho Power Company
Estimated Costs
Air Conditioner Cycling Pilot Program
Year 2003 2004
Number of Participants 200 300
Thermostat Cost/Unit $195 $195
Installation Cost/Unit $50 $59
Thermostat Cost (2 x (3 + 4))$49,000 $73,500
6 Palm Pilots (Thermostat Data Recorders)380
7 System Implementation & Training $19,000
8 System Hosting 000 000
9 Software Fees 250 $5,700
Communications Costs $5,300 800
Control System Cost (Sum 6 : 10)$33,930 $16,500
Interval Meters Cost/Meter $187 $187
Interval Meter Installation Cost/Meter $7 ' $7
Metering Cost (2 x (12 + 13)$38,716 $58 074
Management/Data Analysis/Eval uation/Recru itm ent $115,000 $115,000
Promotion $100 000 $100 000
Ongoing Maintenance $50,000 $50 000
Customer Incentives $3,000 500
Generai Programs Costs (Sum 15: 18)$2t::Q nnn CI:?7? "nnuu,uuv
...-. -,---
Total Cost per Year (5+11+14+19)$389,646 $420,574
Total Cost for two Years (20B + 20C)$810,220
Idaho Power Company
Case No. IPC-O2-
Attachment C
Case No. IPC-02-
Staff Comments
02/21/03
CERTIFICATE OF SERVICE
HEREBY CERTIFY THAT I HAVE THIS 21ST DAY OF FEBRUARY
2003 , SERVED THE FOREGOING COMMENTS OF THE COMMISSION STAFF, IN
CASE NO. IPC-02-, BY MAILING A COpy THEREOF, POSTAGE PREPAID
TO THE FOLLOWING:
MONICA MOEN
IDAHO POWER COMPANY
PO BOX 70
BOISE ID 83707-0070
PETER P PENGILL Y
IDAHO POWER COMPANY
PO BOX 70
BOISE ID 83707-0070
SECRET A
CERTIFICATE OF SERVICE