A remortgage is when a borrower switches their mortgage to a new lender. This could be for a number of reasons, such as wanting to get a better deal on their interest rate, or wanting to borrowing more money against their property. For example, if you took out a mortgage three years ago and rates have since fallen, you may be able to remortgage to get a better deal. Or, if your property has increased in value, you may be able to remortgage to borrow more money against it. There are a few costs associated with remortgaging, such as arrangement fees and valuation fees. However, it's important to compare the overall cost of the mortgage, rather than just the upfront costs. Remortgaging can be a great way to save money on your mortgage, but it's important to compare deals carefully and be aware of the risks before you switch.