‘‘(2) CREDIT
AMOUNT.—The credit amount 
with respect to a highly energy-efficient principal 
residence is— 
‘‘(A) $2,000 in the case of a percentage re-
duction of 50 percent as determined under sub-
section (b)(1)(C), and 
‘‘(B) $4,000 times the percentage reduc-
tion in the case of a percentage reduction of 
less than 50 percent as determined under sub-
section (b)(1)(C). 
‘‘(b) HIGHLY ENERGY-EFFICIENT PRINCIPAL RESI-
DENCE.— 
‘‘(1) IN GENERAL.—Property is a highly en-
ergy-efficient principal residence if— 
‘‘(A) such property is located in the United 
States, 
‘‘(B) the property is used as a principal 
residence, and 
‘‘(C) the projected heating and cooling en-
ergy usage of such property, measured in terms 
of average annual energy cost to taxpayer, is 
reduced by a percentage certified according to 
paragraph (3) in comparison to the energy cost 
of such property if expenditures made by the
taxpayer with respect to energy efficient im-
provements to such property were not made. 
‘‘(2) PRINCIPAL RESIDENCE.— 
‘‘(A) IN
GENERAL.—The term ‘principal 
residence’ has the same meaning as when used 
in section 121, except that— 
‘‘(i) no ownership requirement shall 
be imposed, and 
‘‘(ii) the period for which a building is 
treated as used as a principal residence 
shall also include the 60-day period ending 
on the 1st day on which it would (but for 
this paragraph) first be treated as used as 
a principal residence. 
‘‘(B) 
MANUFACTURED
HOUSING.—The 
term ‘residence’ shall include a dwelling unit 
which is a manufactured home conforming to 
Federal Manufactured Home Construction and 
Safety Standards (24 C.F.R. 3280). 
‘‘(3) CERTIFICATION PROCEDURES.— 
‘‘(A) IN GENERAL.—For purposes of para-
graph (1)(C), energy usage shall be dem-
onstrated by performance-based compliance. 
‘‘(B) 
PERFORMANCE-BASED
COMPLI-
ANCE.—Performance-based compliance shall be
100 
demonstrated if the percent energy cost savings 
for heating and cooling is met with respect to 
a dwelling unit when compared to the original 
condition of the dwelling unit. 
‘‘(C) COMPUTER
SOFTWARE.—Computer 
software shall be used in support of perform-
ance-based compliance under subparagraph (B) 
and such software shall meet all of the proce-
dures and methods for calculating energy sav-
ings reductions which are promulgated by the 
Secretary of Energy. Such regulations on the 
specifications for software and verification pro-
tocols shall be based on the 2005 California 
Residential Alternative Calculation Method Ap-
proval Manual. 
‘‘(D) CALCULATION
REQUIREMENTS.—In 
calculating tradeoffs and energy performance, 
the regulations shall prescribe the costs per unit 
of energy and power, such as kilowatt hour, kil-
owatt, gallon of fuel oil, and cubic foot or Btu 
of natural gas, which may be dependent on time 
of usage. If a State has developed annual en-
ergy usage and cost calculation procedures 
based on time of usage costs for use in the per-
formance standards of the State’s building en-
101 
ergy code before the effective date of this sec-
tion, the State may use those annual energy 
usage and cost calculation procedures in lieu of 
those adopted by the Secretary. 
‘‘(E) APPROVAL
OF
SOFTWARE
SUBMIS-
SIONS.—The Secretary shall approve software 
submissions which comply with the calculation 
requirements of subparagraph (C). 
‘‘(F) PROCEDURES FOR INSPECTION AND 
TESTING OF DWELLING UNITS.—The Secretary 
shall ensure that procedures for the inspection 
and testing for compliance comply with the cal-
culation requirements under subparagraph (C) 
and subsection (c)(2). 
‘‘(c) SPECIAL RULES.—For purposes of this sec-
tion— 
‘‘(1) DETERMINATIONS
OF
COMPLIANCE.—A 
determination of compliance made for the purposes 
of this section shall be filed with the Secretary with-
in 1 year of the date of such determination and shall 
include the TIN of the certifier, the address of the 
building in compliance, and the identity of the per-
son for whom such determination was performed. 
Determinations of compliance filed with the Sec-
102 
retary shall be available for inspection by the Sec-
retary of Energy. 
‘‘(2) COMPLIANCE.— 
‘‘(A) IN GENERAL.—The Secretary, after 
consultation with the Secretary of Energy shall 
establish requirements for certification and 
compliance procedures after examining the re-
quirements for energy consultants and home en-
ergy ratings providers specified by the Mort-
gage Industry National Home Energy Rating 
Standards. 
‘‘(B) INDIVIDUALS QUALIFIED TO DETER-
MINE
COMPLIANCE.—The 
determination 
of 
compliance may be provided by a local building 
regulatory authority, a utility, a manufactured 
home production inspection primary inspection 
agency (IPIA), a home inspector, or an accred-
ited home energy rating system provider. All 
providers shall be accredited, or otherwise au-
thorized to use approved energy performance 
measurement methods, by the Residential En-
ergy Services Network (RESNET). 
‘‘(3) DOLLAR AMOUNTS IN CASE OF JOINT OC-
CUPANCY.—In the case of any dwelling unit which if 
jointly occupied and used during any calendar year