Offsetting rent payment due to "loss of revenue"

[Joseph F.]

My boiler went down over the weekend.  I immediately called my HVAC contractor and they came out the same day.  The boiler needed a specialized part, not something found at the local Lowes or HD.   Given that it was Sunday the part was not available.

On Monday, the commercial tenant claims to have experienced a loss of revenue because the space was too cold to receive (scheduled) clients.

The tenant offset the rent by the amount of revenue alleged to have been lost that Monday.  Rent withheld represents 38% of monthly rent amount.

What does NY state law say?