Seasonal changes for your home HVAC


Summer is waning and fall is approaching. As temperatures cool and the days shorten, the cooling load on your HVAC system will drop and, days will be moderate enough that you will not need heating. This is the perfect time to maintain and service your HVAC system. Here are five steps that you can take to keep your HVAC system running at its peak efficiency and extend its life:

Check Your Thermostat(s)

While the comfort zone for most people is 68 to 72 degrees Fahrenheit, this is not necessarily the most efficient temperature for your thermostat. The Department of Energy recommends setting your thermostat at 78 degrees Fahrenheit during the summer and 68 degrees Fahrenheit during the winter. As summer transitions to fall, it may be time to review your thermostat setting to make sure it is set at the most energy efficient temperature for the season.

If you have a programmable controller, fall may also be the time to review the program settings. Many people alter their schedule during the winter as the sun rises later and sets earlier. Make sure you review the owner's manual for your heating and cooling system since the winter settings for different systems may differ. For example, conventional natural gas or heating oil furnaces run more efficiently when the thermostat is set lower when you are not at home and are programmed to heat up again when you return. Ductless heat pump systems, on the other hand, run less efficiently when the inside and outside temperatures are closer to one another. Therefore, the most energy efficient setting for a furnace thermostat may be different from the most energy efficient setting for a ductless heat pump system.

Check Your Zone Settings

Your heating needs during the winter are different from your cooling needs during the summer. Rooms with large, south and west facing windows may need more cooling during the summer but little or no heating in the winter due to the solar heating. Conversely, rooms with no windows or north and east facing windows may require less cooling during the summer, but more heating during the winter. Fall may be an ideal time to check the zone settings for your ductless heat pump's wall units to make sure they are set for comfort and efficiency during the heating season.

Clean or Replace Air Filters

For many people, summer is allergy season. HVAC filters, and particularly ductless heat pump air filters, capture a lot of dust, pollen, pet fur, and debris. Cleaning or replacing air filters after summer will reduce the risk of allergy attacks from summer allergies later in the year.

Moreover, HVAC systems operate at maximum efficiency when air filters are cleaned or changed at least every three months. Dirty or clogged air filters force the air handlers work harder than needed and reduce the efficiency of the heat exchanger that cools hot air in the summer or heats cold air in the winter.

Clear Debris Around the Compressor

The outdoor unit of an air conditioner system or reversible ductless heat pump includes a compressor to pressurize refrigerant. During the heating season, compressing refrigerant in a ductless heat pump system puts energy into the refrigerant, heating it up. This heat is carried inside, where the refrigerant condenses, giving up heat to the inside air. The cooled refrigerant is transported outside where it absorbs heat, causing the refrigerant to evaporate.

When the compressor unit is dirty, the heat exchanger transferring heat from the ambient air to the refrigerant becomes inefficient because airflow to the evaporator is obstructed. Moreover, debris can clog the compressor motor causing it to seize or overheat.

Tune Up

While it may not necessarily be required every year, fall provides an opportunity to schedule a tune up or repair of an HVAC system. If downtime is required, fall weather usually means that you can survive without experiencing extreme temperatures while the HVAC system is worked on.

Tune ups usually consist of inspecting the mechanical parts, such as motors, fans, compressors, and pumps, for wear and cleaning heat exchangers. Refrigerant lines may be inspected for leaks and the refrigerant level may be checked and recharged, if necessary. The technician may also test electrical components, such as controllers and thermostats.

Bill Hoelzer