Frequently Asked Questions about Heating and Cooling

1) Can frost, ice, dirt or other debris keep the outdoor unit of my cooling system from operating effectively?

It is normal for a heat pump system to develop frost, and even ice, during winter operation. Heat pumps have defrost controls to address ice buildup and help ensure efficient operation. Dirt and debris can affect system performance and efficiency. Most manufacturers recommend that, at the beginning of each heating and cooling season, the system should be serviced by a qualified HVAC professional. While this service generally includes a check of all major system components and equipment operation, it allows the technician to identify and address any concerns, should they exist, thereby helping to prevent more costly repairs, should those concerns be left uncorrected.

2) What is two-stage heating and cooling?

Two-stage heating means the furnace has two levels of heat output: high for cold winter days and low for milder days. The same is true for two-stage cooling on an air conditioner or a heat pump compressor: high for hot summer days and low for milder days. Since the low setting is adequate to meet household heating demands 80% of the time, a two-stage unit runs for longer periods and provides more even temperatures or heat distribution.

3) What do all those air conditioner and heat pump ratings mean?

SEER (Seasonal Energy Efficiency Ratio) is a system for rating the efficiency of cooling equipment. The higher the SEER rating, the more efficiently your system will operate. Minimum SEER is 14. Max is slightly above 25.

HSPF is Heating Seasonal Performance Factor. Minimum is 8.2. Max is slightly above 12.

AFUE is Annual Fuel Utilization Efficiency for a gas furnace. Minimum is 78%. Maximum is 97%.

4) How often should I change my filters?

One (1) Inch filters should be changed at the minimum of once every 90 Days, 2”, 3″, 4″ and 5″ filter thickness, should be changed every six (6) months to a year, but check with the filter manufacturer to see what their recommendations are for their filters. A dirty or clogged filter can cause the system to freeze or overheat depending on the time of year, as well as lost efficiency or restricted airflow to your home.

5) What Is MERV?

MERV stands for Minimum Efficiency Reporting Value. Or in regular people talk, “how effective is your air filter?” MERV ratings range from 1-16. The higher the MERV rating on a filter, the fewer dust particles and other contaminants can pass through it. The American Society of Heating, Refrigerating and Air-Conditioning Engineers designed the MERV scale to represent a filter’s worst possible performance at removing particles .3 to 10 microns in size (about the thickness of a human hair).

Some of the common particles that filters are tested for include pollen, dust mites, textile and carpet fibers, mold spores, dust, pet dander, bacteria and tobacco smoke. Most residential systems can adequately remove airborne contaminants with a filter rated MERV 7-12.

We recommend no more than a MERV 11 for residential use.

5A) Why Not MERV 12?

You might think that a higher MERV rating would automatically be better, but it’s not. The higher the MERV rating, the smaller the pores are for air to flow through a filter. This can create more resistance in airflow than a system is designed to manage, thus making it inefficient. Reducing the airflow in your system can worsen the air quality in your home and put a damaging amount of pressure on the fan of your furnace or AC system.