We have our shop in our converted but separate garage and we run an embroidery machine (not always on), a
DTG (always on), a heat press (not always on), 2 computers (on 12 hrs a day), and 2 window air conditioner units (on about 12 hrs a day) and our bill wet up approx $10 a month. We did factor this into our pricing because it is a business expense that we wouldn't have if we weren't in business.
The heat press in particular causes us to need 2 air conditioners until we put in a heat pump. The other expenses we have that are business realted are insurance and phone.
We love what we do but are not working for free so we add it all into our pricing. If you do enough volume a month it adds very little to the cost of your products.