Why does my air conditioning system cost so much to run when it still doesn’t keep me comfortable?
In the heating and air conditioning industry, we are beginning to understand the cause-and-effect relationships between inefficient building practices and wasting energy and money through energy losses.
New studies demonstrate that indoor air quality is degraded and biological allergy-causing agents are introduced into our homes by leaks in walls, ceilings, windows and air conditioning systems.
All over the country heating and cooling systems are running excessively never achieving acceptable levels of comfort or efficiency because houses are leaky and so are air conditioning duct systems.
Discomfort is rampant as high humidity takes over in homes built with new techniques and new materials but the air conditioning systems are not designed properly for these new homes. As the energy “footprint” decreases in a home, the size of heating and cooling systems should decrease proportionately. Ask the average HVAC contractor how many square feet can be cooled by a ton of air conditioning and he may very well tell you 500 square feet per ton is the standard.
A Simple Example
My house, for example, was built in 1977. If you were to calculate the amount of cooling capacity it would take to cool that home as built with R-19 rock wool insulation in the attic, R-13 fiberglass batts in the walls and vintage double pane aluminum windows, you would find that 500 square feet of that home could be cooled by one ton of air conditioning.
If however you took the same size house and built it today achieving the minimum requirements of today’ more efficient building codes, you would find that the more efficient building structure would allow you to decrease the amount of cooling need so that the square feet per ton ratio would be close to 750 square feet of living space per ton of cooling equipment. This is common sense rule of thumb reasoning.
To illustrate the point, imagine two glasses of iced tea on your kitchen table. One is a 16 ounce glass mason jar mug the other is a stainless steel vacuum insulated travel mug with a screw top lid. It doesn’t take a degree in rocket engineering to figure out which container will keep the iced tea cooler longer. To put it another way, which mug will have more ice left in it after one hour? You guessed it! The travel mug wins. So it is with your super insulated house; it is easier to cool with less cooling power. So this is a more with less equation. If you build a house with more insulation and more efficient windows, you can cool the same size house with less air conditioning plain and simple.