The state is not offering the loan, banks are through the utility companies. If you are a customer of the participating utility, you are paying an assessment on your bill for the MassSave program. Through that program -- that is, through the funds you've already contributed -- you can get a free energy assessment, funding to help you insulate, and interest free loans for certain projects. If you don't have NG in your area, you can get loans for other projects that will save you money. Check it out.
I have already passed on the "free" energy assessment. I don't want anyone associated in any little way with the government on my property. I kind of doubt that any energy improvements will pay off in my lifetime.