My company pays 100% of my personal apartment rent, and I receive an additional W2 for the percentage of non-office space as personally taxable income. This means that 100% of the money paid is a corporate tax deduction, and the parts paid for my office never hit my personal income.
I recently learned that because my flat is a 2 bathroom, one of those bathrooms can be included in the "office space" calculation as well, as offices require bathrooms.
Standard disclaimer: I am not an accountant or a lawyer, so this is layperson advice. Consult with a professional.
As mentioned above, make sure it has a door, and close it. Train your housemates/family/partner/SO/whatever to leave you alone while you're "at work".