Static pressure is an essential component of heating and air conditioning maintenance. It is described as the resistance to airflow in features, such as ductwork. High static pressure is a sign of problems with your HVAC unit. It is essential to recognize this problem early to take appropriate measures to repair or eliminate it. This will ensure that your HVAC system performs better and lasts longer.

What Is Static Pressure?

This is the resistance to airflow in your ductwork. With HVAC units, you want to have the right balance of static pressure as too little or too much can cause issues, such as energy inefficiency and premature system failure.

The simplest way to understand static pressure is to look at a water hose when dispensing water. If you partially put your thumb over the hose’s tip and change the diameter of the opening, pressure increases, speeding up the water.

This is the same case with air. If you reduce the size of the opening in the ducts, it raises air velocity. For instance, you can reduce an eight-inch air duct to six inches with low static pressure. This will elevate the static pressure. To properly maintain your HVAC equipment, the static pressure should be 0.5 inches at the lowest noise. Incorrect static pressure can stress your HVAC system and even break it down. Static pressure can also affect the efficiency of your system, which will impact the amount you incur on energy bills.

High Static Pressure Indicators in HVAC Units

The following are indications of high static pressure in your HVAC system:

Uneven Cooling and Heating

Also known as experiencing cold or hot spots, this is where some areas in the home that are not the same temperature as the others. Often, it occurs because of weak air circulation in one or several parts of the HVAC system where the air is not able to fully circulate into the ductwork. Consequently, some rooms in the house do not receive sufficient heating or cooling.

Increased Energy Bills

If your utility bills suddenly increase, you could be having a problem with your HVAC system. If the static pressure is thrown off, your AC or furnace will work extra hard to circulate air in your house. The more resistance it faces, the harder it works to deliver hot or cool air. That extra strain will increase the amount of energy your system consumes, making you pay more on your utility bills. To determine if your high energy bills are due to high static pressure, contact Thermo Direct to assess your HVAC unit. If your HVAC system strains too long, it could potentially experience system failure and break down.

Noise From the HVAC System

Loud mechanical sounds or the sound of air rushing are other signs of a problem with your HVAC system. We have talked about how your AC or furnace strains with increased resistance. Due to this, you can hear that extra effort. The blower motor working at maximum capacity produces more noise, just as when your car engine roars when you floor the gas pedal. You may also notice the sound of air getting drawn harder into and out of the vents due to more significant force.

It is essential to note that these signs are not exclusive to high static pressure. However, if you notice all three, there is a high chance that it could be the issue.

Causes of High Static Pressure

To determine if the static pressure is high in ductwork, you will need credible electrical, heating, and air conditioning experts, such as Thermo Direct, to take measurements and identify the problem. High static pressure in ductwork can be a result of the following:

Indoor Coil Is Too Small or Dirty

If the coil in your HVAC unit is too small or dirty, it can lead to high static pressure. The coil is in charge of the heat transfer process. During the winter, it provides heat that circulates throughout your home. During the summer, the refrigerant liquid that carries thermal energy out of your home evaporates and goes through the coil. Heat transfers occur in the coil to convert the refrigerant into a liquid state, circulate back into the system, and pull out more hot air. So, it’s obvious that the entire system has a problem if the coil has a problem!

The coil generates air resistance, which is unavoidable. However, the resistance is not significant enough to cause problems. But, if the component is dirty, then you have serious issues. Any debris, dust, or other junk stuck on the coil prevents air from flowing freely as expected. On the other hand, a tiny coil has the same effect as a dirty one, because it is not the proper size.

Undersized Air Returns

Improperly designed or undersized ductwork increases static pressure. However, we will focus on undersized air returns in this section.

These ducts draw air in from a room and circulate it back through the HVAC system. It is an essential and often overlooked element of the air circulation process. If the air returns are undersized, you will have a problem with your HVAC unit.

The situation is like when you breathe through a straw. Although you can do it, you must draw extra hard to get sufficient air through a smaller opening than your nostrils or mouth. Your heating system works the same way when faced with high static pressure. It works harder to draw the quantity of air necessary to keep circulating.

There is another issue to consider. The air conditioning process entails circulating refrigerant in a closed loop throughout the system. With insufficient air, the refrigerant loop is thrown off. Over a prolonged period, this can lead to significant problems, including costly repairs and breakdowns.

Air Filter is Too Restrictive or Clogged

The air filter in your HVAC system is naturally designed to be in contact with the airflow. However, when all other components are working correctly, it does not affect it significantly. And the benefits are more than any pressure loss. An air filter works as a screen to prevent contaminants such as dirt, dust, and allergens from entering the air and ducts. As air goes through the screen, the air filter traps the particles with the screen, adding resistance. Typically, this is not an issue; however, failure to change the filter within a few months allows debris to build up and prevent proper airflow, which ultimately causes resistance.

Certified Electrical, Heating and Air Conditioning Experts

Thermo Direct is a reliable electrical, heating, and air conditioning company in Raleigh, NC. We have been serving The Triangle community since 2000 with quality workmanship and customer service. Despite being primarily known for heating and air conditioning, we also handle several other services to add to homeowners’ comfort in their homes. We provide duct repair and electrical services, weatherization, smart thermostats and indoor air quality solutions. Visit our website for reviews and specials or financing! Our options are customized to your budget, home, and individual needs. So, call us today to your electrical, heating, and air conditioning needs!

company icon