It is therefore worth reviewing the mortgage as a whole to see if switching to a better rate with a different lender could tackle the shortfall issue and reduce the amount you pay each month.
Martin Lewis, of the consumer website MoneySavingExpert.com, said many people could save money by switching to one of the fixed-rate deals currently on offer.
Switching gears, the loan market default rate inched up to 1.4% in January from 1.3% at yearend, though remains well inside the historical average of 3.3%.
Health insurers and pharmacy-benefit makers are already seizing on the money-saving opportunity that switching patients from Lipitor to a cut-rate Zocor would provide.
By keeping the federal funds rate close to zero for three more years, and switching from shorter to longer-term securities, the Fed hopes to spur investment and growth.