Consent to Let and the Reverse Situation
Most people are familiar with the concept of consent to let — the permission a residential mortgage lender grants to allow a borrower to let their property when they need to move out temporarily. The equivalent process in reverse — notifying a buy-to-let lender that you intend to occupy the property yourself — does not have a standard name, but the underlying principle is similar: you need the lender's agreement to change the use of the property from the basis on which the mortgage was granted.
Buy-to-let mortgages are assessed and priced on the assumption that the property will be let to tenants and that rental income will service the mortgage. When you move into the property yourself and it is no longer generating rental income, the basis of the lending fundamentally changes. The lender needs to reassess affordability based on your personal income rather than rental income, and the product terms may change as a result — including the interest rate, which is often different between residential and buy-to-let products.
The first step when planning to move into a buy-to-let property is to contact your lender and explain your situation. Many lenders will confirm in writing that they are aware of the change and will provide guidance on the process for converting to a residential product. Some may grant a short period of temporary occupancy while you arrange the full conversion, though this is at the lender's discretion and should not be assumed.
If you are currently in a fixed rate period on the buy-to-let mortgage, there may be an early repayment charge payable if you need to exit the product early in order to switch to a residential mortgage. The cost of any ERC needs to be weighed against the cost of remaining on the BTL product. Some lenders will allow an internal product transfer to a residential deal without triggering the ERC, but this varies by lender and product. Your broker can help you assess the options and costs.
Affordability Assessment: From Rental Income to Personal Income
The biggest practical difference between a buy-to-let and a residential mortgage assessment is how affordability is measured. Buy-to-let mortgage affordability is primarily assessed against rental income — the lender checks that the rental income covers the mortgage payment by a sufficient margin, typically 125% to 145% at a stressed interest rate. The borrower's personal income is of secondary or no relevance for many buy-to-let products.
Residential mortgage affordability is assessed against the borrower's personal income — their salary, self-employment income, pension, or other earnings. The standard income multiple approach applies, with lenders typically lending 4 to 4.5 times gross annual income for most borrowers, and up to 5 to 5.5 times for higher earners or those in strong professions. There is no rental income to offset the borrowing — the full mortgage payment must be supported by personal income.
This shift can work either favourably or unfavourably depending on your personal income and the mortgage balance outstanding. If you have a strong personal income and the property has significant equity — meaning the outstanding mortgage balance is relatively low — the affordability assessment on a residential basis will be straightforward. If the property carries a high mortgage balance relative to the rental income it generated, and your personal income is modest, there may be affordability challenges in switching to a residential product.
Where affordability is tight, it is worth exploring whether any additional income — such as a second earner, rental income from another property, or a lower mortgage balance achieved by making overpayments — can improve the position. A whole-of-market broker will run the numbers across multiple lenders to find the most favourable affordability assessment for your circumstances.
