The Residential Tenancies Act is the legislation that governs landlords and tenants in Ontario.
Under this law there isn’t a notice the landlord can serve the tenant when the house is put up for sale. The landlord can only serve the form N12 once an Agreement of Purchase and Sale is signed, if there are 3 or fewer residential units and the purchaser is planning to live in the house. The landlord is not responsible to pay the tenants any difference in rent in these circumstances, as long as there are grounds to terminate the tenancy.
As of July 21, 2020 the landlord is required to give the tenant one month’s compensation, or offer the tenant another unit that is acceptable to them, if pursuing the N12 notice on behalf of the purchaser. The compensation must be given before the termination date on the notice.