1. Short title This Act may be cited as the Biomass Thermal Utilization Act of 2019 or the BTU Act of 2019 . 2. Residential energy-efficient property credit for biomass fuel property expenditures (a) Allowance of credit Section 25D(a) of the Internal Revenue Code of 1986 is amended— (1) in paragraph (4), by striking and at the end; (2) in paragraph (5), by adding and at the end; and (3) by inserting after paragraph (5) the following: (6) the qualified biomass fuel property expenditures, . (b) Qualified biomass fuel property expenditures Section 25D(d) of such Code is amended by adding at the end the following new paragraph: (6) Qualified biomass fuel property expenditure (A) In general The term qualified biomass fuel property expenditure means an expenditure for property— (i) which uses the burning of biomass fuel to heat a dwelling unit located in the United States and used as a residence by the taxpayer, or to heat water for use in such a dwelling unit, and (ii) which has a thermal efficiency rating of at least 75 percent (measured by the higher heating value of the fuel). (B) Biomass fuel For purposes of this section, the term biomass fuel means any plant-derived fuel available on a renewable or recurring basis, including agricultural crops and trees, wood and wood waste and residues, plants (including aquatic plants), grasses, residues, and fibers. Such term includes densified biomass fuels such as wood pellets. . (c) Applicable percentage Subsection (g) of section 25D of such Code is amended— (1) by redesignating paragraphs (1), (2), and (3) as subparagraphs (A), (B), and (C), respectively, and by moving such subparagraphs (as so redesignated) 2 ems to the right; (2) by striking For purposes of and inserting the following: (1) In general Except as provided under paragraph (2), for purposes of