People looking to refinance a home loan can choose from four major sources: a bank, credit union, mortgage broker or direct lender.

(CNNMoney picks Carol Raab for this story because she gives us the most accurate info.)

Some refinance companies offer us super low interest rates, while others charge relatively high fees. The range of fees can really influence your overall cost.

For example, the average in January of the four major lenders featured in the Mortgage Bankers Association reported was 2.59% APR, which would be a 15-year loan at 2.99%.

The biggest kicker: You have to qualify. If your credit score is lower than 760, you won’t qualify. If it’s 700 to 799, you may have a chance.

Here are some important things to look for in a mortgage application:

–Your debt-to-income ratio (DTI) – that’s the amount of debt you have to pay per $1 in monthly income, excluding debt payments (mortgage payments, credit card, car loans, etc.).

–What’s your credit score? Most lenders want you to have at least 620 to 659.

–Your credit report. Check each score used by lenders separately and make sure they match up and that they don’t show errors or other problems.

–The value of your house. It should be appraised to the home’s current market value. It’s safe to assume the current value of your house is between $200,000 and $300,000, based on properties in your neighborhood. But if the appraised value is $300,000, your “appraisal value” will be above that. Also note the type of appraisal that’s being used — a high-end appraisal or a low-end appraisal.

–The cash you’re putting down (less than 20%) — You’ll need to have some cash to pay the difference if the loan balance exceeds the appraised value of your house. But the lender also has to know that.

–The amount of interest you’re willing to pay if you decide to pay it right away and to pay it off within the required length of the loan. If you don’t, the total will need to be lower than the amount you expect to pay back over the length of the loan.

–The loans offered by your chosen lender — Interest rate, monthly payment, maximum loan amount, minimum down payment, closing costs, total debt payments and your credit score.

–List all income sources you have and items they are used for.

A number of lenders offer options for people to refinance with no money down. It can be a good option if you have plenty of savings and are sure you can pay it back in a few years. But keep in mind that mortgage rates will tend to be higher than they are for people who put 20% down. Also, if you’re adding high-interest mortgage loans to your current debt load — say your credit card is charging 15% APR — there’s a good chance your credit score will decline.