[Highland Park] Energy Audit and Garden Center Recommendation

Hi: I am looking into doing an energy audit and was wondering if anyone has had that done, who they used and whether they would recommend the company.  I'm also looking for an extensive garden center. The ones I have visited so far have a small selection of both type and size of plant. I know some of you have lived in the DC area and might be familiar with Benke's or American Plant Food. I am looking for something along those lines. Thanks in advance.Teri