Many homeowners strive to select and invest in the best AC systems to serve them well and for longer periods of time. However, this is not one the easiest decisions to make bearing in mind the varieties in models available in the market today. Lots of manufactures have come up with systems that are targeted at both low income and high end homeowners.
Among the most looked at factors include the type of system, the accessory options as well as the efficiency level. However, there is one factor that is often overlooked despite it being very important in the selection of an AC unit; proper sizing of the equipment.
The HVAC industry has a standardized procedure for properly sizing AC equipment. A number of homeowners and contractors use measurements from the previous units, the square footage of the home or worse still a rule of thumb. Improperly sizing of the AC system can effectively lower its efficiency and significantly shorten its lifespan.
Sizing AC Systems
Modern AC systems are more efficient compared to old systems especially those that have more than 10 years in service. During system replacement, caution should be exercised to ensure you pick a correct-sized AC unit that will guarantee you comfort, efficiency, and low operating and maintenance costs in the course of the systems life. According to national surveys conducted on homeowners, it has been discovered that many HVAC contractors do not size AC systems correctly.
One of the most common mistakes made is oversizing. This makes the entire system difficult to install, operate at a less-than-expected level of efficiency and break down more often. Systems that are oversized also create large temperature swings in your indoor environment. Due to the fact that oversized systems do not run long enough to dehumidify air in the indoor environment, the overall result is a clammy feeling coupled with unhealthy mould growth in air conditioned homes.
Why Most Older AC Systems are Oversized
Some time back, homes were not as tightly constructed as they are today; as such it was common to find installed AC units that were two to four times the required capacity. Later on people started adding windows, weather-stripping, caulking and insulation to their homes. This resulted into oversized systems. Such home improvements that allow you to reduce heat loss in summer and heat gain in winter must be matched with the appropriate AC systems. This will assure you comfort as well as less money spent on utility bills.
The Correct Way to Size a System
Other than simply reading the nameplate of the existing AC, you should also consider a number of other factors for correct sizing. Among these factors include: the local climate, insulation levels, air infiltration rates, shape, size and orientation of the house, number and ages of occupants, window location and the type home appliances.
As a homeowner, you must always insist that contractors use a correct sizing calculation before signing the contract. In the United States, Manual J, which is a Residential Load Calculation developed by Air Conditioning Contractors of America (ACCA) is one of the recommended sizing method. The calculation procedure is also further simplified by Sizing Heating & Cooling software.
