Ask MetaFilter | Community Weblog: "Without knowing your exact figures it is hard to say.

You may want to consider the fees associated with refinancing- Lenders policy, Title search, origination, underwriting, tax service, recording, etc. (These can add up quick.) If you paid your principal down by what it will cost to refinance, you may have the 20%.

Depending on how long you have had your current loan and what property values are doing in your area, it may be better to just get a new appraisal reflecting 20% equity. If the 'comps' in your area have gone up since your last appraisal or if the appraiser can find some better comps then you may have the equity you need. One of the best ways to make your appraisal go up is by adding heated and cooled square footage to your house. You can close in a garage or porch or sun room for more living space and add the value you need."