If you are renting out your home or a portion of it and claiming Rental Income from it, you may be able to deduct some expenses for your new furnace and basement renovations. When claiming rental expenses, you first will need to determine whether they are capital or current expenses. A new furnace and renovation are usually considered to be capital expenses.
You can refer to the criteria given by CRA (Canada Revenue Agency) to determine if the expenses are capital or current expenses in this link: Current or Capital expenses
For more information, please visit the CRA (Canada Revenue Agency): Capital Cost Allowance
TurboTax: Rental Property Expenses: Current or Capital?