All air conditioning units have a SEER rating.  That stands for Seasonal Energy Efficiency Ratio.  This number represents the ratio of the cooling output over the season divided by the energy consumed in watt hours.  It is a measure of air conditioner and heat pump cooling efficiency.  The measurement is taken over the course of a typical cooling season.  The higher the number, the more efficient the unit. 

The minimum standard for a SEER rating is 14.  A maximum rating can range between 21 and 25.  Most newer air conditioning units will fall somewhere in this range.  The SEER rating is a maximum rating but doesn’t mean the unit always performs at that level.  Older air units may only have a SEER rating around 8 or 9.  This means those units are not very energy efficient.  The SEER rating is labeled on the yellow “Energy Guide” sticker found on the air conditioning unit.

When replacing an old AC unit, you’ll want to choose one that has a SEER rating of 13 or higher.  That upgrade will significantly reduce the cooling costs for the homeowner.  Today’s air conditioning units are 20-40% more efficient than models that are 10 years old.

AC units with a low SEER rating usually run on one speed.  These older units turn off and on more frequently.  They also tend to cool unevenly, leaving hot and cold spots in the house.  Units with a higher SEER rating generally have a variable speed compressor.  They provide greater indoor comfort and remove more humidity (moisture) from the air.

When getting ready to purchase a new unit, how high a SEER rating is high enough?  The answer varies and will depend on several factors including:

• How many hours on average will the system run each day?
• At what temperature will the thermostat be set?
• How much insulation does the home have?
• Are the windows good quality, or do they leak?
• How often will the filters be changed?
• How regularly will the system receive routine maintenance?

The Energy Star website has an energy savings calculator that can help homeowners decide what SEER rating to consider for their new unit.  Your HVAC contractor should also provide clear information and work with you to determine what best meets your needs.

Air filters are designed to protect the blower fan and the evaporator coil in your furnace or heat pump fan-coil by removing particulates from the air as it is passes through the system. These filters are made of porous membranes that allow air to pass through but trap particles of dust, dirt, pollen, pet dander, and other pollutants. The accumulation of these particles on the filter or evaporator coil reduces air flow and decreases the efficiency of the HVAC system. Changing filters regularly improves indoor air quality, extends the life of the system and reduces energy cost.

In the average family home, filters should be monitored at least every 90 days. Filters in homes with pets should be monitored more frequently. Most service companies have maintenance programs that call for two visits a year. Technicians should make the customer aware of how often filters should be changed and instruct the homeowner how to do it themselves, if it is necessary to the proper operation of their systems.

Filters are rated using the “minimum efficiency reporting value” or MERV rating system.  There are several different types of filters:

Fiberglass/synthetic filters – These flat panel disposable filters are the most common type and are the least efficient. They are inexpensive and catch only larger particles moving through the system. They do not remove harmful contaminates or improve air quality. Their MERV rating is very low, usually in the low single digits.

Polyester and pleated filters – These filters are a slight bit more expensive that fiberglass filters but are better quality and longer lasting. Pleats increase surface area, which catches more airborne particles. The polyester material is also less porous and is a better choice for people with allergies or asthma. MERV rating for these devices generally touch on the lower double digits.

Electrostatic filters – This type of filter has self-charging fibers that attract and trap particles from the air. Two types are available – disposable and a type that is washable. Disposable ones should be changed regularly, just like the previously mentioned filters, about every 6 months. Washable ones should be cleaned regularly and dried completely before reinstalling. The washable ones can last between 1 and 4 years with proper maintenance. MERV rating for these devices range into the mid double digits.

HEPA filters –  Most residential systems cannot accommodate HEPA filters. They are more commonly used in hospitals and commercial systems. They are very high efficient, trapping the most harmful particles. These devices do, however, decrease the efficiency of the central systems to which they are attached. MERV ratings for these devices are at the top the scale.

Before you’ll need to run the air conditioning full time during the summer, schedule a tune-up for the HVAC system.  Spring is the perfect time to prepare the system for warm weather.  Keeping the HVAC system properly maintained can save homeowners time and money in the long run by extending the life of the system.  A qualified technician should inspect and clean the unit.  It’s generally easier to book an appointment with an HVAC company during the spring, before the weather gets too hot.  Here are some seasonal maintenance items that should be performed.

Change filters- Filters that have been used all winter are dirty and should be discarded.  Clogged filters reduce air flow and cause the system to run longer than necessary.  Clean filters improve air quality in the home by removing dust and allergens from the air.  Organic material that accumulates in the unit can cause mold to grow.  HEPA filters may be appropriate if family members have allergies or respiratory problems.

Check air unit– The air conditioning unit hasn’t been used all winter, so a technician will ensure the unit is cooling properly.  The condensation lines and drains should be inspected and cleaned.  Moving parts should be lubricated.  The thermostat should be examined to ensure it is properly calibrated.

Inspect outdoor unit– The outdoor unit should be inspected and cleaned.  Debris should be removed from the coils.  The outdoor fan should run smoothly.  The refrigerant lines should be inspected, and the coolant level evaluated.

Adjust humidifier– If the home has a furnace mounted humidifier, it should be turned all the way down or off.  Spring is a good time to clean and make repairs to the humidifier so that it will be in proper working order next winter.

Properly maintaining your HVAC system in the spring can help homeowners avoid costly repairs.

Many people ask me about the difference in the cost of heating and cooling their homes with gas heating and electric cooling as opposed to heating and cooling with a heat pump. The following are some thoughts to help you make such a decision.
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