Key legal question
Whether the cost of installing a wood stove qualifies as an energy-saving expense deductible for cantonal/state tax.
Extracted holding
No. Installing an additional wood stove in an apartment already heated by an oil central heating system does not produce meaningful energy savings and is not a deductible energy-saving measure.
Extracted reasoning
Under the cantonal rule, deductible energy measures must save non-renewable energy in an existing building. Because the oil heating was not replaced, but only supplemented, the measure did not actually reduce energy consumption; any substitution effect was at most minimal and dependent on user behavior.