Interest-only mortgages involve paying only the mortgage interest each month until you have repaid the entire mortgage. You will still have to refund the original amount you borrowed at the end of the mortgage. If you are planning on selling the property, interest-only payments could be an ideal option as you will pay smaller monthly figures, although you should expect some additional conditions.
However, be aware that if the housing market crashes, you may be at risk of making a loss on your property and be required to pay the initial amount you borrowed. Therefore, lenders will ask you to provide details on how you will pay the mortgage back.
Repayment mortgages are higher every month because you pay a proportion of the original amount and additional interest. However, your debt will have been completely paid off at the end of the mortgage period.