Usually, things like furnaces & ac units would be considered personal use items. You would only be able to claim these things if you could prove that you bought them for your business.

It is my understanding that you can claim furnace/water heater/utilities etc. repairs and maintenance as part of a business expense for a use-of-home self-employed business.  Does having to replace the furnace (or water tank etc.) not qualify as a repair if the thing has completely conked out?  I can have clients coming to a cold house in the winter.

As per the Canada Revenue Agency (CRA): You can deduct part of your maintenance costs such as heating, home insurance, electricity, and cleaning materials. You can also deduct part of your property taxes, mortgage interest and capital cost allowance (CCA). 

For clarification please call the CRA at 1-800-959-8281.

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