I have allergies to gas and had to disable my heating system. Can I deduct the cost of operating a pellet (biomass) system?

There’s no clear answer, and you may have to argue your position for this deduction if your return is questioned. On the one hand, the Tax Court allowed a deduction for the extra cost of organic food compared with the cost of regular (chemically treated) food where a doctor prescribed the diet to treat a specific condition such as allergies (see, e.g., Theron G. Randolph, 67 TC 481 (1976); Leona Von Kalb, TC Memo 1978-366). And a district court allowed a deduction for the cost of constructing a concrete home for an allergy sufferer (Lawrence S. Zipkin, D Minn, 2002-2 USTC ¶50,863).

However, the Tax Court denied a deduction for the cost of ripping up carpeting and installing a wood floor by a person with allergies (Ilija Mitic, TC Memo 2000-144).