@ThomasM125 But as I understand all those pro-rated (by sq ft) deductions are specifically for the functionality of the "whole home" rather than the just the space used for business. For example, the water bill is a common documented example of one that can be deducted for home office. Hardly any home offices actively install a sink and use water inside their home office, but it's part of the home's general utilities so it uses the prorated deductible formula.
I would think all mechanical systems / utilities fall in the same bucket here, not differtiated by if a specific utility happens to be used within the confines of the business space .
Does the IRS specifically differentiate what it means by "whole home" when the homestead has two structures on the property separated by a breezeway?
