Yes, you do. A valuation is required when you refinance your home loan to determine how much risk you pose. A valuation protects the lender by ensuring that you’re not borrowing more than your property is worth.
The lenders will rely on the valuation to confirm whether or not your application meets their lending criteria. The valuation will determine your current LVR and:
Your interest rate (as rates are tiered to your LVR)
If the security (home) is acceptable
If you have enough equity available (if you’re refinancing to access equity, cash-out, debt consolidation, etc)
Between the time you bought the property and the time you decide to refinance, significant changes to the value of your home may occur. Since you are taking out a new home loan during a refinance, your lender will need updated information regarding your financial situation.