Replacement of Air Conditioning and Heating Systems. Replacing a unit is a major home improvement decision. Overall cost, utility rebates, manufacturer’s difference, overall efficiency, and more will come into account. These have the ability to become extremely confusing, however with Mechanical Heating & Air, this process will be slightly easier. As our expert technicians will assist you in deciding whether it is necessary to replace or maintain your recent unit. If it comes down to replacing your furnace or air conditioning unit, we are able to provide you with many different options to choose from.