Throughout the last summer season, you came to a grave realization: your central air conditioner isn't providing the same amount of cool air to your home as it once did. For this reason, you're now in the market for a new unit. However, before you spend a large sum of money on a new unit, hire an HVAC contractor to help you sort through these three issues. Otherwise, you may find that your new unit still doesn't meet your expectations.

Appliance Performance Ratings

Although the cooling power (or BTU output) of an air conditioner is an important statistic to keep in mind, it shouldn't be the only specification to which you pay attention while shopping for a replacement unit.

In addition to BTU output, your replacement air conditioner needs to be more energy-efficient than your current unit. The efficiency of your new unit will be rated in either EER (energy efficiency ratio) or SEER (seasonal energy efficiency ratio). The minimum EER or SEER rating of modern air conditioners is controlled by the government and changes nearly every year. To ensure that your replacement unit is in compliance with federal law, make sure your unit meets or exceeds the minimum requirement.

Cooling Requirements

Every home is different—especially when it comes to air conditioning. For this reason, it's necessary to carefully calculate the cooling requirements of your specific home. In addition to the specifications of your new unit, several factors will determine how well your replacement unit will be able to cool your home. By adding these factors into your equation for your home's cooling requirements, you'll be able to select a new unit or modify your HVAC infrastructure to improve your system's cooling efficiency.

Square footage, wall insulation, windows, and even sunlight penetration will affect the cooling requirements of your home. Additionally, structural issues, such as air leaks, will further affect your home's cooling requirements.

Unless you've learned about HVAC systems and calculations in a formal setting, chances are you won't be able to make an accurate calculation of your home's cooling requirements by yourself. For this reason, you should make sure the HVAC technician that installs your new air conditioning unit performs thorough calculations of your home's cooling needs and informs you of the external factors that affect their choice of unit and system modifications.

If your new unit doesn't meet your home's cooling requirements, or if the cooling requirement calculations are performed incorrectly, then your HVAC system's cooling ability won't improve with the installation of your new unit. If you underestimated your home's cooling requirements, then your new unit can even perform far worse than your current one.

Duct Sizing

Your air ducts are the unsung heroes of your HVAC system. Responsible for handling both the heat produced by your furnace and the cool air produced by your air conditioner, your air ducts must remain in good condition in order for your heating and cooling appliances to keep your home comfortable.

However, when you replace your air conditioner with a unit of varying BTU output, your air ducts can become problematic.

When your existing ductwork was installed, its size was determined by the CFM (cubic feet per minute) of your blower motor and the output of your appliances. If your new air conditioner has different output levels than your current one, or if your blower will be replaced along with your air conditioner, then your air ducts may end up being either too small or large to serve as ideal ventilation shafts. As a result, air will travel inefficiently throughout your ducts and into your home.

If you haven't already factored these issues into your replacement process, then don't continue shopping or installing your new unit until you hire a professional HVAC technician to handle them. Ignoring these issues and continuing to blindly replace your air conditioner will have you calling for an HVAC inspection upon the arrival of the next summer season. For more information or assistance, contact a local air conditioning installation company.