Work Space in the Home Expenses

Question about the "Expenses which you incurred for the entire home." If I work from home for my employer and want to claim some things like electricity, heat, & water I'm having a little confusion understanding the turbo tax form you do this on. It has electricity, heat and water and then three boxes, GST Taxable, HST Taxable and Zero Rated and Exempt.

I'm in Alberta so HST isn't applicable. So if the combined total for those three services is $3100 and the GST on that is $100 would I put $100 under GST Taxable and then $3000 under Zero Rated & Exempt? I am aware I need a T2200 from my employer in order to claim these expenses.