How Long Should You Set Your Heating and Cooling Cycles to Last?

Setting HVAC cycles accurately helps ensure that your A/C or furnace provides maximum efficiency, lowest costs and optimum cooling or heating performance. "Cycling" simply refers to how many times the unit turns on and off every hour. The duration of on and off cycles is an important metric to evaluate how efficiently an HVAC system is operating. Here are some reasons why:

• Consequences of cycles that are either too short or overly long include excessive wear and tear on critical components such as the air compressor or furnace heat exchanger.

• Poor performance is another common result: The indoor environment and overall comfort may be impacted by a variety of symptoms, including erratic temperature swings, excess indoor humidity, and overly hot or cold rooms.

• Noisy system operation as the unit cycles on and off frequently — or, conversely, runs almost constantly — is also annoying.

• Excess energy consumption and higher operating costs are another factor.

Generally speaking, a central A/C or furnace should cycle on for about 15 to 20 minutes before cycling off again. In other words, about three to four cycles per hour. Both short-cycling and overly long cycles can be indications that something is amiss. Here are some examples of potential issues related to setting HVAC cycles:

• Short-cycling may indicate that the BTU capacity of the air conditioner or furnace is too large for the size of your home. The unit produces too much cooling or heating when it cycles on. Therefore, it shuts off too rapidly. This can degrade indoor comfort and also put excessive wear and tear on critical system components, leading to premature failure.

• Long cycles can result from problems such as insufficient airflow—most commonly caused by a clogged air filter or ductwork issues such as excessive leakage. Also, if the unit is undersized, i.e., the BTU capacity of the furnace or air conditioner is too small for the size of the house, it may run almost nonstop to achieve the thermostat setting. Another common cause of long-cycling specific to air conditioners is a refrigerant leak.

For qualified professional service to diagnose issues relating to setting HVAC cycles, contact Air Assurance.

Why You Shouldn’t Use Registers for Temperature Control

Even though you may read online articles about controlling the indoor temperature in a room by adjusting the register, it’s not a good idea in most situations. Doing so can harm your HVAC system, which will eventually cause a problem requiring professional attention.

What It Does

When you close off the vent in a room, the amount of air pressure in the ductwork increases. Ductwork is designed to carry a certain amount of air pressure and closing even one register, especially if it’s not far from the air handler, raises it beyond its capacity. Over time, the extra pressure will weaken the seams and joints in the ductwork, creating leaks.Leaking ductwork drives up energy bills because conditioned air is lost before it reaches your rooms. The leaks pull in dust from the areas through which they run. In homes with vented gas appliances like water heaters and furnaces, the leaks create backdrafts that can pull carbon monoxide into your rooms.It may seem like a contradiction, but the higher airflow pressure inside the ductwork will reduce the amount of air going through air handler, which stresses the heating and cooling components inside the air handler. In the summer, lower airflow contributes to a frozen evaporator coil that may contribute to compressor failure, the system’s most expensive part. In the winter, reduced airflow causes the furnace to run hotter, which harms all its parts.

Better Options

The best way to control the indoor temperature in a room is by using a zoning system, which uses automatic dampers in the ducts to control the airflow. Each zone has its own thermostat and when it needs conditioned air, it sends a signal to a control panel. This part turns the HVAC system on, opens the damper and the air flows to that zone.In lieu of zoning your home to control the indoor temperature, it’s a good idea to leave the registers open. In the long run, the energy costs will be lower than the repairs. For more information, contact Air Assurance, providing HVAC services for Broken Arrow homeowners.

Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, call us at 918-217-8273.

HVAC During Mild Weather

Setting the thermostat for fall, when the weather is still mild, can be rather perplexing. Since it may be still a bit too warm in the daytime to turn off the air conditioner altogether, or not yet chilly enough at night to turn on the heating, you may have to do some adjusting with your fall HVAC settings.

Let the Fresh Air In

If the weather allows, by all means, turn the system off in fall and fling open the windows so you can enjoy some fresh air before winter arrives. Be sure you turn the system to "off" so that it doesn't come on while the windows are open.

Setting the Thermostat

If you've created an energy-efficient schedule with your air conditioner by raising or lowering the thermostat for periods throughout the day depending on when people are home, sleeping or inactive, you will probably need to adjust the schedule as the weather cools, and for time changes.For the fall, it may be you will want to change that schedule to turn the air conditioner on for just a couple of brief periods each day, and leave it off for the rest of the day so you can open windows. Or, as the season advances and it gets chillier, you will want to turn on the heating just for brief times in the morning, when people are getting ready for work, and in the evening, when you're dining or getting ready for bed.To save money, you can use ceiling fans, portable fans and even an occasional space heater to cool off or warm up those who aren't comfortable with your thermostat settings. If they are chilly, they can add layers of clothing or an extra blanket at night. That way, you may even be able to turn the system off altogether at night.

Obviously, the chances for a serious cold front to make its way into our region will mount as fall advances, so be ready to reset the thermostat as needed.Need more advice on fall HVAC settings? Contact Air Assurance of Broken Arrow.

Our goal is to help educate our customers in the Tulsa and Broken Arrow, Oklahoma area about energy and home comfort issues (specific to HVAC systems). For more information about other HVAC topics, call us at 918-217-8273.