Using Home As an Office Advice on claiming expenses when your home is your working space. Last updated: 30 November 2020 According to the tax authorities, if you set aside an identifiable part of your home and use it solely for business (e.g. if you use a room or part of one only as an office) then a proportion of running costs, such as insurance, heat and light and mortgage interest, is allowable. If the part of the property used for business purposes is also used for some other purpose at the same time, then no deduction may be due. If the part of the property used for business is used exclusively for this purpose, for only part of the time, you can claim part of the running costs, apportioned by reference to the time it is so used. It is important to note that if you use part of your home exclusively for business, you may be liable for Capital Gains Tax when you come to sell it. There are different views on this.