103 
as a principal residence by 2 or more individuals the 
following rules shall apply: 
‘‘(A) The amount of the credit allowable 
under subsection (a) by reason of expenditures 
made during such calendar year by any of such 
individuals with respect to such dwelling unit 
shall be determined by treating all of such indi-
viduals as 1 taxpayer whose taxable year is 
such calendar year. 
‘‘(B) There shall be allowable with respect 
to such expenditures to each of such individ-
uals, a credit under subsection (a) for the tax-
able year in which such calendar year ends in 
an amount which bears the same ratio to the 
amount determined under subparagraph (A) as 
the amount of such expenditures made by such 
individual during such calendar year bears to 
the aggregate of such expenditures made by all 
of such individuals during such calendar year. 
‘‘(4) TENANT-STOCKHOLDER IN COOPERATIVE 
HOUSING CORPORATION.—In the case of an indi-
vidual who is a tenant-stockholder (as defined in sec-
tion 216) in a cooperative housing corporation (as 
defined in such section), such individual shall be 
treated as having made his tenant-stockholder’s pro-
104 
portionate share (as defined in section 216(b)(3)) of 
any expenditures of such corporation and such credit 
shall be allocated pro rata to such individual. 
‘‘(5) CONDOMINIUMS.— 
‘‘(A) IN GENERAL.—In the case of an indi-
vidual who is a member of a condominium man-
agement association with respect to a condo-
minium which he owns, such individual shall be 
treated as having made his proportionate share 
of any expenditures of such association and any 
credit shall be allocated appropriately. 
‘‘(B) CONDOMINIUM
MANAGEMENT
ASSO-
CIATION.—For purposes of this paragraph, the 
term ‘condominium management association’ 
means an organization which meets the require-
ments of paragraph (1) of section 528(c) (other 
than subparagraph (E) thereof) with respect to 
a condominium project substantially all of the 
units of which are used as principal residences. 
‘‘(6) JOINT OWNERSHIP OF ENERGY ITEMS.— 
‘‘(A) IN GENERAL.—Any expenditure oth-
erwise qualifying as an expenditure under this 
section shall not be treated as failing to so 
qualify merely because such expenditure was 
made with respect to 2 or more dwelling units.
105 
‘‘(B) LIMITS
APPLIED
SEPARATELY.—In 
the case of any expenditure described in sub-
paragraph (A), the amount of the credit allow-
able under subsection (a) shall (subject to para-
graph (1)) be computed separately with respect 
to the amount of the expenditure made for each 
dwelling unit. 
‘‘(7) ALLOCATION IN CERTAIN CASES.—If less 
than 80 percent of the use of an item is for nonbusi-
ness purposes, only that portion of the expenditures 
for such item which is properly allocable to use for 
nonbusiness purposes shall be taken into account. 
‘‘(8) COORDINATION WITH OTHER CREDITS.— 
Property which would, but for this paragraph, be eli-
gible for credit under more than one provision of 
this section shall be eligible only under one such pro-
vision, the provision specified by the taxpayer. 
‘‘(9) YEAR
CREDIT
ALLOWED.—The credit 
under subsection (a)(2) shall be allowed in the tax-
able year in which the percentage reduction with re-
spect to the principal residence is certified. 
‘‘(10) WHEN EXPENDITURE MADE; AMOUNT OF 
EXPENDITURE.— 
‘‘(A) IN GENERAL.—Except as provided in 
subparagraph (B), an expenditure with respect
106 
to an item shall be treated as made when the 
original installation of the item is completed. 
‘‘(B) EXPENDITURES PART OF BUILDING 
CONSTRUCTION.—In the case of an expenditure 
in connection with the construction of a struc-
ture, such expenditure shall be treated as made 
when the original use of the constructed struc-
ture by the taxpayer begins. 
‘‘(11) PROPERTY
FINANCED
BY
SUBSIDIZED 
ENERGY FINANCING.— 
‘‘(A) REDUCTION OF EXPENDITURES.— 
‘‘(i) IN
GENERAL.—Except as pro-
vided in subparagraph (C), for purposes of 
determining the amount of expenditures 
made by any individual with respect to any 
dwelling unit, there shall not be taken into 
account expenditures which are made from 
subsidized energy financing. 
‘‘(ii) SUBSIDIZED
ENERGY
FINANC-
ING.—For purposes of clause (i), the term 
‘subsidized energy financing’ has the same 
meaning given such term in section 
48(a)(4)(C). 
‘‘(B) DOLLAR LIMITS REDUCED.—The dol-
lar amounts in the table contained in subsection
107 
(b)(3) with respect to each property purchased 
for such dwelling unit for any taxable year of 
such taxpayer shall be reduced proportionately 
by an amount equal to the sum of— 
‘‘(i) the amount of the expenditures 
made by the taxpayer during such taxable 
year with respect to such dwelling unit and 
not taken into account by reason of sub-
paragraph (A), and 
‘‘(ii) the amount of any Federal, 
State, or local grant received by the tax-
payer during such taxable year which is 
used to make residential energy property 
expenditures with respect to the dwelling 
unit and is not included in the gross in-
come of such taxpayer. 
‘‘(C) EXCEPTION FOR STATE PROGRAMS.— 
Subparagraphs (A) and (B) shall not apply to 
expenditures made with respect to property for 
which the taxpayer has received a loan, State 
tax credit, or grant under any State energy pro-
gram. 
‘‘(d) BASIS ADJUSTMENTS.—For purposes of this 
subtitle, if a credit is allowed under this section for any 
expenditure with respect to any property, the increase in