5 Reasons to Replace that Old AC Unit

The old adage, “Out of sight; out of mind,” too often describes the attitude the average home or business owner in Chicago takes toward their HVAC systems. Even well-maintained AC units do age out of effectiveness. Here are five reasons commercial businesses as well as single family homeowners should consider replacing their aging AC units.


In Chicago the air temperatures climb to their peak in July, averaging a high of 84.2F. The humidity often rises with the heat averaging 68.5% in the same month. Combining the temperature and relative humidity, Chicago residents can expect the air to feel closer to 90F. A failure of an AC unit in the Chicago summer months proves uncomfortable at the least, and competing for service with others whose systems have also failed can spell long days of discomfort or present a serious health risk.

An HVAC system, given proper maintenance, can perform well for an average of 15 years. However, units that saw poor to no maintenance could fail in as little as five years. According to ENERGY STAR, the Environmental Protection Agency’s (EPA) arm rating product effectiveness and efficiency, owners should consider replacing their HVAC units when the units exceed 10 years of age.

Though an older air conditioning system continues to operate, it may no longer cool the space evenly. More humidity in a home or an office also adds discomfort and is a sign the AC system is no longer running efficiently.


As HVAC systems age, they often need more frequent repairs. One common issue occurs when the AC unit leaks refrigerant, the odorless gas used to cool and condition the indoor air. To keep the AC working effectively, leaky units need a recharge. As of January 1, 2020, the EPA completed its phase out of R-22, the refrigerant used in older HVAC units. To recharge their aging systems, the homeowners must pay the higher price to obtain the diminishing supplies of recycled or stockpiled R-22. Systems using this refrigerant may need to be retrofitted or replaced to use the new environmentally-friendly replacements, R-410A or R-421A.


As an AC unit ages, it also becomes less efficient, prompting a rise in monthly utility bills. ENERGY STAR includes the Seasonal Energy Efficiency Ratio (SEER) in its ratings of HVAC products. SEER measures the efficiency of an air conditioner, showing how efficiently the cooling system operates over a season. The higher the SEER rating, the more efficient the system.


Modern air conditioners have SEER ratings from 13 to 21; older models may rate 6 to 10 SEER. Replacing an older AC unit with a new higher-rated product saves electricity, reducing utility bills. The availability of new “Two-Stage” technology, replacing the older “Single Stage” unit, allows a newer air conditioning system to automatically adapt to the cooling needs and provides more effective humidity removal.



Older HVAC systems are much less environmentally-friendly than their newer counterparts. As noted earlier, older units used R-22 (“Freon”) as the refrigerant. The EPA rates R-22, also known as HCFC-22, as a Class II ozone-depleting substance (ODS), and completely phased out the use of R-22 in new air conditioners, which now use refrigerants less damaging to the ozone. (Consult the EPA,, to access a list of acceptable substitutes for residential and light commercial AC.)

The most energy greedy part in an AC unit is the compressor. Newer air conditioning systems offer “Two-Stage” compressor technology as noted above. This configuration uses two compressors (or a single two-speed compressor) to remove the heated vapors, allowing the refrigerant to cool. The “Two-Stage” system saves energy by automatically reducing the work load on the compressor on cooler days.

Combining a programmable thermostat with a new AC unit is a simple way to make a system environmentally-friendly. The thermostat can automatically turn off an AC unit or raise the temperature when no one is home saving energy without sacrificing comfort.


An older AC unit originally sized for the space may no longer fit the need, particularly if the owner has expanded the square footage of the home or office. For maximum efficiency, the size of an air conditioning unit must fit the space need.

On average a 1,500 square foot house needs a system supporting 24,000 BTUs. If the system is too small, it will not adequately cool the space; an overly large system wastes energy. Plans to expand living or work space should include a consultation with an HVAC professional to determine the right size HVAC unit for the added square footage.

Air Quality

Old, poorly functioning air conditioning units can degrade indoor air quality. Pollutants such as dust and dirt build up in air ducts; conditioned air passing through the ducts introduces these pollutants to the interior of the home. These substances cause irritation to the eyes, nose, and throat, and threaten to exacerbate respiratory problems such as asthma. Homeowners should change filters often or the buildup of dirt on these filters ruins their effectiveness.

The presence of humidity in the air ducts also contributes to mold growth. Older air conditioning units, less efficient and possibly undersized, prove less effective in dehumidifying the air passing through these ducts, introducing moisture and creating a breeding ground for mold. Individuals with mold allergies may have serious reactions when exposed to mold spores.

When should a business or home owner replace an aging air conditioning unit? If the current unit no longer provides comfort and good air quality, if it requires more repair and costs more to run, or if the aging system is not eco-friendly, it’s time to replace it with a modern unit. There are five reasons – comfort, cost, compatibility, conservation, and air quality – to call an HVAC professional to assess the need and recommend the right-sized, energy efficient unit for the home or office.

Ravinia Plumbing is always happy to assess individual needs and determine the best course of action to ensure safe, functional operation. Those looking for electrical contractors in Chicago are encouraged to contact the company at 847-579-5565 or online at

Show More


Leave a Reply

Your email address will not be published.

Related Articles

Back to top button