Many homeowners have been sold a forced air heating system because they believed it was the only system that would also give them air conditioning. As a result, they get a forced air system that isn't comfortable or efficient at either heating or cooling. For maximum comfort and efficiency heating should come from the floor and cooling should come from the inside walls near the ceiling.

For summer cooling in buildings with radiant floor heating a separate air conditioning system is installed with the ducts entering the room at ceiling level along the inside walls. This type of installation is the most comfortable, the most efficient and requires minimal duct work. The installation really isn't all that expensive. The more you think about separate heating and cooling systems the more sense it makes. Heating and cooling demands for various rooms are generally the opposite. As a result it is virtually impossible to design a forced air system that ill give you satisfactory comfort levels during the winter heating season and the summer cooling season.

For example, a kitchen area, with a normal cooking load, will have a low demand for heat in the winter. In summer, the same kitchen would have a higher demand for air conditioning. If we want our bedrooms cooler for sleeping a forced air system would have to deliver less warm air in the winter and deliver more cold air in the summer. Bathrooms have the opposite problem. Offices with extra heat being generated from computers and photocopiers also create a problem. For optimum comfort and efficiency a forced air system would hve to deliver less warm air in the winter and more cool air in the summer. Because of the differences in heating and cooling demands it is virtually impossible to design one system that is efficient at both heating and cooling.

With separate heating and cooling systems both systems can be designed to optimize comfort and efficiency. It is the only way you can achieve the ideal heating curve summer and winter. In a recent retrofitting contract, radiant floor heating was installed in a home which had a forced air heating system. During initial discussions the homeowners asked if a larger air conditioning unit should be installed because it had not kept up to cooling demands on hot days. The original air conditioning unit was left in place but the ducts were moved to the inside walls near the ceiling. While a scientific energy study was not conducted the homeowner reported improved comfort levels with the original air conditioning unit running about half the time it had run with the old duct system blowing air our from the floor.

As we've said before, for maximum comfort and efficiency, heating should come from the entire floor and in the summer, air conditioning should come from the inside walls near the ceiling.