A/C Units & Historic Homes

Old homes and modern air conditioning seem to contrast, but there are options. You can achieve summer comfort in the most humid climates using central air, with tradeoffs between price, payback, and aesthetics.

It could prove to be very difficult to stay within budget when you need to add an AC unit to an old home. Let's say your heating's fine—you have radiators or a radiant floor system; however, to condition a house built before central air, you'll have to find a home for the bulky compressor or air handler. Do you shove the trunks aside in the attic? Take up basement space? Ducts to deliver cool air to all the rooms can chop up the building's historic fabric. Are you willing to sacrifice closet space?  Obviously, there is a lot to consider with this particular project.

Cooling capacity should be determined by a contractor and be based on a load analysis using the Air Conditioning Contractors of America Manual J. The contractor might also use a computer program that accounts for the building's particular construction, such as surface areas of exterior walls, insulation levels, window glazing, and air infiltration. At best, old houses have some attic insulation, but the walls are rarely insulated. By today's standards, the windows are loose. That's why there's no off-the-shelf answer or square-foot solution to home air conditioning.  Once you know just about how much cooling you need for your home, you may begin this project.

Any SEET air conditioner with more than 12 will provide reasonable utility bills; however, our vintage buildings with their loose windows, doors, and gaps around baseboards and moldings, tend to have high levels of infiltration. In humid climates, infiltration brings in higher levels of moisture. The goal of installing central air is to lower the ambient temperature, but even more, to control humidity. Lower humidity may allow you to be comfortable at a higher thermostat setting, which means the compressor won't run as often.

With all the important choices you would need to make within this project, make sure you hire the help of a licensed contractor that has knowledge and experience with historic homes to make sure you do not run into any unforeseen issues in the long run.

If you are looking to buy, sell, or have any questions regarding Miami Historic Homes, call 305-986-7041 or fill out the contact form. We would love to connect with you regarding your interest in Historic homes and we specialize in renovating, researching, purchasing or selling Historic Homes in South Florida.