I live in northeast Ohio and need to replace a number of Pella windows on my home. I have had Pella quote me for the windows but they use contract installers and the first installer gave me a quote for $3600 to install 7 replacement windows. three of the windows are double casements, one is a double casement with a half circle transom, two are standard double hungs and one is a fixed picture window. The cost amounts to average of $600 per window and that seems excessively high to me. Are the installers factoring in the tax credit that homeowners can get qand upping their cost accordingly. What shoult the cost be for this installation?