The CMHC Mortgage Loan Insurance premium is calculated as a percentage of the loan and is based on the size of your down payment. The higher the percentage of the total house price/value that you borrow, the higher percentage you will pay in insurance premiums.
Remember: without mortgage insurance you may avoid the insurance premium but you’ll typically pay much higher interest rates and additional administrative fees. At the end of the day, for the vast majority of borrowers, the cost of CMHC Mortgage Loan Insurance is more than fully offset by the savings achieved. Source
CMHC Insurance Premiums are not Subject to HST