Mortgage rates fell this week to the lowest level on record, giving consumers added incentive to lock in low payments for home purchases and refinanced loans.

The average rate for 30-year fixed loans sank to 4.69 percent, from 4.75 percent last week, mortgage company Freddie Mac said Thursday.

That's the lowest point since Freddie Mac began tracking rates in 1971. The previous record of 4.71 percent was set in December. Rates for 15-year and five-year mortgages also hit lows.

The Obama administration has launched programs to help borrowers refinance if they owe up to 25 percent more than their home's value and have loans owned or guaranteed by mortgage giants Freddie Mac or Fannie Mae.

About 291,000 homeowners have participated as of March.

Given the costs of refinancing, some mortgage experts say a refinancing can be worthwhile if you can shave at least 0.75 percentage point from an existing rate. Others suggest waiting until you can lower your rate by at least a point.

Despite some lenders' ads, refinancing is never free. A fee normally goes to the mortgage broker or lender. There are also fees for title insurance, a new appraisal, document processing and other charges. Often, mortgage brokers or lenders create the appearance of a "no fee" mortgage by adding the costs to a total loan amount or by charging a higher interest rate.

People considering refinancing should factor in such fees. They should also calculate how many months it would take to recover them. For those who expect to stay in their home for two years or less, the fees might outweigh the savings from a lower rate.

Rates on 15-year fixed-rate mortgages fell to an average of 4.13 percent. That was the lowest on records dating to September 1991. It was down from 4.2 percent a week earlier.

The rates do not include add-on fees known as points. One point is equal to 1 percent of the total loan amount.

The nationwide fee for loans in Freddie Mac's survey averaged 0.7 a point for 30-year loans. The average fee for 15-year loans was 0.6 of a point.