We chose Core Air to replace our air-conditioning unit because of their relationship with Cosco. The sales person that came to our home to give us the estimate was very professional. He arrived on time and was very thorough in taking measurements to assure us that we were getting the right size unit for our home. The Installers were also prompt and did a great job in making sure that the unit fit in the tight space that we had available and that everything was sealed appropriately. The old unit, apparently, was not sealed properly and we had a lot of air leaking around the supply duct. It is too early for me to evaluate the efficiency of the unit(Lennox) but Core Air appears to have delivered what was promised.