Years ago, I had a roommate. He had a bedroom and bathroom dedicated completely for his private use in a separate area of my rather small home, but he constantly stayed in the front room and dining room with me. I couldn’t understand it. Was he just a friendly, social guy? A couple of years later I found a new roommate and had the exact same experience. Why? This guy seemed like a pretty private person, why wouldn’t he stay in his part of the home? By the time I found a third roommate, I found out what the problem was and realized a change was needed, and it wasn’t my roommate.
That small third bedroom in my home never cooled down. You could freeze to death in the rest of my home, but that little room never felt cool enough. I could feel the cool air blowing from the vent, the room was relatively small, but the air never felt cool. I splurged to make that roommate happy and bought a window air conditioner to help cool his room. But why was that necessary?
I contacted my A/C service company and had them come take a look. I found out about heat load and heat sources. In this case it was very simple; this relatively small room had a very large window. While the rest of the home is surrounding by large shade trees which significantly reduced the temperatures, this small bedroom was on the westerly exposed side of the house with no shade trees. Combined with the large low efficiency window, it was too much for this space. It doesn’t take much.
Your builder or A/C company should look at things such as this. Internal sources of heat can be just as troublesome. The number of people typically occupying a room, the direction the room faces and the exposure to the sun, the proximity to appliances such as washers and dryers and kitchen appliances, the height of the ceilings and other factors that contribute to the heat load need to be taken into account by a design professional to calculate how much air is required to cool or heat the space. They can calculate the CFM breakdown, or Cubic Foot of air per Minute. This information is used to properly design the duct system for the unit. It’s not something you should do yourself. If it’s properly done, you will think nothing of it. If it’s not, it will drive you crazy and you’ll never be able to find a comfortable solution. It’s that important.
I never really appreciated the difficulty my roommates were having all those years ago, but once I became informed I made the changes necessary. I could have saved myself a lot of trouble and called a professional at the first sign of trouble. Do yourself a favor if you find yourself in a similar situation.