Often, we see where additional sections of batt insulation have been laid where there is no insulation in the attic, in hopes this will fix the problem with hot and cold spots. However, it really is not offering any relief for the homeowners. Fiberglass is only effective when enclosed on all sides. And with too little insulation throughout the attic, heat is radiating down in the summer with little resistance and escaping from the rooms below in the winter.
There are hundreds of holes allowing conditioned air in your living space to escape, and the ductwork connections are just one of them. Top plates, utility penetrations, and fixture housings also create gaps for conditioned air to rush out of your home to be replaced with unconditioned air at the bottom of the house. It leaves you with uncomfortable rooms and your HVAC running all the time trying to get the house to the right temperature.
Too little insulation means little resistance to the temperatures in the attic. In the summer, the attic is hotter than the outside temperature. It heats up the ceiling, and that heat radiates into the rooms below making them hot, uncomfortable, and hard to cool down. In the winter, the attic is the same temperature as outside, making the ceiling cold. As heat rises through the home, it meets the cold ceiling, is cooled down, and falls. This cycle, called convective looping, continues leaving the home feeling cold and drafty, and difficult to warm up.
In many homes, we find that there is ductwork in the attic, it is a logical spot to put the equipment. However, it is left subject to the extreme conditions of the environment. In the summer, the duct lines and the air in them heats up to the same sweltering temperature of the attic. When cold air is pumped through to try and cool the home, it is heated up by the duct lines and the hot air in them, making it more difficult to cool the home down. The reverse is true in the winter when the attic is the same temperature as it is outside.
Attics are a huge source of energy loss in homes. They naturally have hundreds of holes allowing conditioned air to escape from the living space and are subject to the extreme temperatures of summer and winter.