Weekly survey of mortgage lenders with the lowest rates: Rates bubble higher

Mortgage rates took a fractional turn higher this week. The Yahoo Finance weekly survey ranks lenders by the lowest annual percentage rate (APR), which includes lender fees. Read on to see the 10 lenders with the lowest rates this week.

Read more: See our top picks for mortgage lenders for first-time home buyers.

Here are the 10 mortgage lenders with the best interest rates this week, as determined by our survey of the lowest mortgage rates on 30-year, fixed-rate conventional loans. The following numbers are each lender's annual percentage rate (APR).

Two national credit unions again top our list this week of mortgage lenders with the lowest rates. Navy Federal and PenFed Credit Union have home loan rates that are only fractionally apart; however, their advertised fees differ significantly. You can see the points charged in the table below.

It's an important lesson, because higher fees don't always mean lower rates. Rocket Mortgage is at the bottom of our list with a survey-high 7.039% APR, and charges nearly 2 discount points. There are several lenders offering better rates and lower fees.

Of the 16 national lenders surveyed on July 13, Third Federal, Rate, Bank of America, Fifth Third Bank, PNC Bank, and Rocket Mortgage did not rank among the top 10 lenders sorted by annual percentage rates. An APR difference of 0.897 percentage point separated the top lender, Navy Federal, from the bottom-ranked Rocket Mortgage. That's further proof that shopping multiple lenders can lead to significant savings.

These are sample mortgage rates found on lender websites and are based on generic assumptions. Lenders advertise 30-year mortgage rates based on varying credit scores, down payments, and other credit qualifications. Even where you live affects your mortgage rate.

If a mortgage lender required additional borrower information to provide a sample rate, we supplied a median home value and credit score, with a 20% down payment based on a home located in the Midwest.

The key to securing the lowest mortgage rate is shopping around, which could save borrowers up to an average of $44,000 over the life of a 30-year loan, according to analysis by Realtor.com.

We're also looking for details that you will want to consider. Often, borrowers focus on the offered interest rate, as that's what lenders typically highlight. However, the mortgage annual percentage rate, or APR, is the most important number.

APR includes both the interest rate and lender fees (for example, the mortgage origination fee ), so it is the most accurate measure of your annual borrowing costs.

Lenders often include mortgage discount points to lower the interest rate they offer. That's where things can get confusing.

First off, discount points are prepaid interest — an up-front fee paid at closing that reduces your interest rate. Although lenders often include discount points in their advertised rates online, buying points is optional.

Each point represents 1% of your loan amount and generally lowers your interest rate by about 0.25%. For example, one point on a $400,000 mortgage would cost $4,000 and reduce a 6.25% home loan to 6%.

Just remember, no matter what the lender puts in an advertised rate or in a loan offer, when you get a Loan Estimate , and you see discount points under the lender fees section, you can say "no" and have them removed. But your rate will be higher.

If possible, when shopping with three or more lenders, have each of them provide a quote for a mortgage rate with zero discount points. Then, focus on the APR for an accurate side-by-side comparison of rates and fees.

See the table below to understand the Yahoo Finance methodology for determining which mortgage lenders have the best rates this week. Remember, we are sorting by APR, which includes both the interest rates and mortgage lender fees, including points.