Beating the Heat: Windows or AC?
By Erin Carlson Mast
Last August, we published a post that discussed historical, passive methods of cooling the Cottage. The desire is to use these methods of cooling the Cottage, the methods the Lincolns themselves would have used, to enhance the visitor experience and appreciation for the authentic structure.
While historical methods of cooling are preferred, during the design phase, we did decide to introduce a high-velocity ventilation and air conditioning system in the Cottage for days when the Cottage may be overwhelmingly uncomfortable if not dangerous for any of our visitors. The system is zoned so that we can control ventilation and cooling in three separate areas of the Cottage, giving us the ability to use air conditioning on the second floor (unsurprisingly hotter than the first floor) while maintaining comfort with outside breezes or ventilation on the first floor.
So when do we use the AC and when do we use the windows? The windows, the vast majority of which are original to the house, offer an enormous amount of versatility in cooling the Cottage. Most of the windows are double-hung sash windows, allowing us to open them from the top (to allow hot air to roll out) or bottom allowing cool breezes to provide wonderful cross-ventilation. The windows also have exterior louvered shutters, and nearly all of their original interior wood panel shutters, allowing us to cut down on the amount of heat-generating sunlight (from partial to black-out) that reaches the interior.
Several types of weather conditions in the spring-fall months make it necessary to close up the Cottage and run the AC for the comfort and safety of our visitors: 85 degrees coupled with high humidity; any day designated “Code Red” for unhealthy air quality in DC; severe storms or heavy rain; and high pollen counts (the brown porch can become so covered in a single day it looks lime green) are three such events that make it prudent to shut windows and shutters to protect our visitors–and the Cottage–and run the ventilation or AC to keep the Cottage comfortable.