Too soon to dump 80/20 mortgage

Dear Dr. Don,
We just purchased a home and moved in a month ago. We got an 80/20 loan. I've already been told that our mortgage will be sold within 60 to 90 days. I would like to convert to a 30-year fixed for the whole amount. How long do I need to wait before checking into changing it to a 30-year?
-- Patricia Payments

Dear Patricia,
The reason that people choose an 80/20 loan, besides not having funds available for a down payment, is to avoid paying private mortgage insurance, or PMI. The homeowner closes on a second mortgage at the same time he closes on the first mortgage. The second mortgage can be a fixed-rate, fixed-payment home equity loan, a variable rate home equity line of credit or a hybrid that behaves like a HELOC, or a home equity loan at different points in the life of the loan.

I know real estate prices have been moving higher this season, but it's hard to imagine a situation where in less than two months' time you've built up enough equity in the home that it makes financial sense to refinance your home with just a first mortgage.

When a first mortgage lender has a loan-to-value above 80 percent of the appraised value of the property, they will require PMI. The less equity the homeowner has in the property, the higher the monthly PMI payment. This Web site's PMI calculator will help you estimate the PMI payment.

The originating lender selling the mortgage shouldn't influence your decision to keep or refinance the loan. The next lender will have that same right.

If you're in an 80/20 mortgage, and the second is a variable-rate loan, you're right to be worried about what's going on with the variable rate. It's hard, however, to make the jump that it's time to refinance after just one month in these loans.