If you have registers and thermostats throughout your house, we'll need to access those-- and possibly relocate furnishings also. http://vietmycorp.vn/index.php?language=vi&nv=news&nvvithemever=d&nv_redirect=aHR0cDovL3BvbGltZW50b3Nyb2JlcnRvLmNvbS5ici8