Most people don’t spend enough time getting to know their HVAC systems. It’s actually a little odd that a unit that is so essential to the health, wellness, safety, and comfort of your home is overlooked by most people. In fact, it’s pretty much the norm to never think about your HVAC system until something goes wrong with it!

You might be wondering why it’s worth it to spend time learning about the different parts of your HVAC system when you’ll just be calling a tech to handle anything that goes wrong. Knowing what’s inside your HVAC system is all about being an empowered homeowner. Here are the top reasons to have a basic understanding of common HVAC terms:

  • Knowing common HVAC terms will make it easier for you to describe the problem if you’re on the phone with a technician to request a service visit.
  • Some techs may be able to help you do a quick fix over the phone if you have a basic understanding of the anatomy of your HVAC system.
  • You’ll understand what’s on your HVAC repair bill better! This leads to better trust and peace of mind!
  • Knowing what different parts of your HVAC system do may make you feel more confident about conducting routine cleaning and maintenance that can prolong the life of your HVAC system.

The good news is that it’s very easy to learn the common terms used in the HVAC world. You’ll find that taking just a minute to become familiar with the buzzwords that represent the components that heat and cool your home is worth it the next time you have to describe what’s going on when placing a call for service. Let’s start with an easy one. The term HVAC actually stands for Heating, Ventilation, and Air Conditioning. Take a look at the rest of the common HVAC terms that all homeowners should know!

1. Indoor Air Quality (IAQ)

Let’s start with a “fancy one.” IAQ is so important for the health and safety of your home! HVAC technicians talk about IAQ in relation to filtration for a home’s HVAC unit. In fact, you might want to consider bringing up a filtration system with your HVAC service company if you’ve noticed lingering odors, dust, or debris in your home. This is the key to getting truly fresh air in your home without the need to spray an air freshener to cover up poor IAQ.

2. Seasonal Energy Efficiency Ratio (SEER)

Here’s another one that impacts performance. A SEER rating is the rating that tells you just how efficient your air conditioner actually is based on a national standard. A unit’s SEER rating is calculated by dividing cooling output by electricity input. If your unit is newer, you may remember seeing the SEER rating when you were comparison shopping. However, most homeowners with older SEER ratings have no idea how their units rank. Any SEER rating falling between 13 and 22 is considered good. Getting over 20 means you have a very efficient system! A lower SEER rating could justify an upgrade of your HVAC system because you’ll enjoy a more comfortable house while saving money on energy costs.


This phrase becomes important if you’re shopping around for a new heater or air conditioner. ENERGY STAR is a program developed through the Environmental Protection Agency (EPA) that’s aimed at lowering energy usage through smarter purchasing decisions. ENERGY STAR appliances are designated as appliances that help to save energy. In addition to being great for the planet, these appliances help homeowners to save money by being more efficient. You may also be able to get some federal tax credits for purchasing certain ENERGY STAR appliances and units at various times.

4. Heat Pump

Your heat pump is the lifeblood of your “comfortable” home season after season. A heat pump has the job of moving heat. That means circulating warm air through your home by drawing in warm in during the colder months. During the warm months, the heat pump pushes hot air from inside your home to the outside. Everything comes to a standstill when the heat pump stops working!

5. Compressor

Your air conditioner’s compressor keeps the refrigerant circulating. It’s actually the process of the refrigerant absorbing or releasing heat that keeps your home at your target temperature. Compressors are pivotal parts of both single-stage and two-stage cooling units.

6. Condenser Coil

Condenser coils can either collect or release heat. Refrigerant that begins in a gas form travels from the evaporator coil to the condenser coil to turn into liquid. Next, fans blow over the coil to send heating or cooling throughout your home!

7. Refrigerant

Refrigerant is a coolant chemical that produces a cooling effect when it’s expanding or vaporizing. It’s used in nearly all cooling systems today. Just remember that refrigerant levels should be checked as part of regular maintenance.

8. Thermostat

You might be asked for a reading of your thermostat if you ever place a call for service on your HVAC system. The thermostat is really the “first line of defense” in detecting what’s wrong with a unit. Your unit’s thermostat is a temperature-control device responsible for monitoring and regulating the system’s performance. It’s also the tool you use to set the temperature you want to feel comfortable!

9. Flue

While the word flue has traditionally been associated with fireplaces, you don’t need a chimney at your house to have a flue. Your flue is actually the vent that removes byproducts made during your furnace’s combustion process. Your flue should be cleaned and inspected annually!

10. Load Calculation

This is a pivotal phrase when you’re auditing your HVAC unit’s performance. You’ll also hear it said a lot if you’re in the process of upgrading your home’s heating and cooling system. A load calculation determines how much heating and cooling your home needs. An HVAC tech calculates how much heat is gained and lost to determine the size of the unit needed to keep your home safe, efficient, and comfortable!

11. Tonnage

Have you ever heard a technician refer to tonnage when talking about your air conditioner? Tonnage measures the cooling capacity of an air conditioner. A ton of cooling equals 12,000 BTUs (British Thermal Units) per hour. A BTU refers to how much heat an air conditioner can remove from the air. When shopping for a new unit, doing a BTU-to-BTU comparison between products is helpful for measuring how powerful units are in relation to price and size.

12. MERV

MERV means Minimum Efficiency Reporting Value. It measures the ability to filter particles from the air. MERV ratings go from 1 to 20. You’re generally in very good standing if you have a MERV rating of 16 because this is where you get to hospital-quality filtering power.

13. Heat Exchanger

You’ll only hear this term if you have a gas furnace! The heat exchanger is the area where combustion happens in a gas furnace. Your unit’s heat exchanger pulls air into the unit to warm it up using transferred heat. Next, the blower motor moves the air throughout your house using your ductwork. A broken heat exchanger means that your gas furnace can’t actually get the temperature to the right level for distributing warm, toasty air on cold days.

14. Whole-Home Zoning

Whole-home zoning is a setup that allows you to heat and cool areas of your home independently. While it’s common in new homes, zone heating can be added to existing homes. Here’s a look at the benefits:

  • You can save money by turning down heating or cooling in areas of the house you don’t use.
  • Your system won’t have to struggle to correct the temperature to account for differences in every single room of your house. In addition to saving you money on energy costs, this can also extend the life of your HVA system.
  • You can make the areas of your home where you spend the most time more comfortable without feeling wasteful.
  • Members of your household can select their own preferred temperature settings.

When you call Delaware Heating and Air for service, you can count on impeccable responsiveness and customer care regardless of how many HVAC phrases you know. However, we encourage you to become more familiar with your HVAC system as part of a commitment to making your home more comfortable, more efficient, and safer. Reach out to us today for all of your maintenance and repair needs!