A buy-to-let mortgage is a type of mortgage sold specifically to people who view their property as an investment, rather than a home. If you plan to purchase a property, then rent it to a tenant in order to generate an income – most lenders would require you to apply for a buy-to-let mortgage; not a residential one.
Buy-to-let mortgages are typically more expensive than an average mortgage that a home mover would need. Deposits for BTL can range from a minimum of 25%, up to 40%.