In general

The term “housing cost amount” means an amount equal to the excess of—

(A) the housing expenses of an individual for the taxable year to the extent such expenses do not exceed the amount determined under paragraph (2), over

(B) an amount equal to the product of— (i) 16 percent of the amount (computed on a daily basis) in effect under subsection (b)(2)(D) for the calendar year in which such taxable year begins, multiplied by (ii) the number of days of such taxable year within the applicable period described in subparagraph (A) or (B) of subsection (d)(1).