HVAC Acronyms

Common HVAC Acronyms

Common HVAC Acronyms

HVAC AcronymsIf you’re looking for a new HVAC unit or thinking of upgrading, you may be confused by the hundreds of acronyms.  Below is a list of 12 of the most common HVAC acronyms.

1. ACH

Air changes per hour, or ACH, is the rate air enters and exits a room in one hour. How do you measure ACH?   Take the air volume added to or removed from a space and divide by the volume of the space.  A higher number means the room is better ventilated.

2. BTU

The BTU or British Thermal Unit is the amount of heat needed to raise one pound of water by one degree fahrenheit.   Knowing a facilities’ BTU requirements makes it easier to help you choose the right HVAC system.

3. BTU/H

British Thermal Units per hour measures the amount of heat your air conditioner removes in one hour.

4. CAV

Constant air volume, or CAV, is a type of HVAC system. The system always puts out the same amount of air, but raises and lowers the air temperature, keeping the room temperature consistent.  This type of system is usually found in smaller commercial buildings.

5. FCU

A fan coil unit, or FCU, uses a coil and fan to heat or cool a room without any ductwork.  They are available in a variety of designs including ceiling, floor-mounted and freestanding models.

6. FAF

Fresh Air Fraction, or FAF, is the ratio of the outdoor air intake and the total airflow supply rate.


Heating seasonal performance factor, or HSPF, rates the efficiency of a heat pump during a heating season. To calculate the rating, take the total heat output and divide it by the total electric output during the period of time.  A higher rating indicates that the unit is more energy efficient.

8. MAU

A makeup air unit, or MAU provides buildings with conditioned heated and cooled fresh air. MAUs are used in buildings that need high indoor air quality (IAQ).

9. RTU

A rooftop unit, or RTU, is a type of HVAC system often found in large commercial locations.  Also referred to as a package unit, it conditions air without taking up any indoor space. These units are usually found in restaurants, stores, warehouses, and shopping centers.

10. SEER

The seasonal energy efficiency ratio, or SEER, rates the efficiency of an air conditioner.  The SEER rating takes the cooling output and divides it by the total electricity during a typical cooling season.

11. CFM

This acronym refers to cubic feet per minute. It measures how many cubic feet of air passes a specific point in one minute. This measurement is one factor in determining the size of AC unit you need.

12. FPM

FPM or feet per minute refers to the speed of airflow. While CFM measures how much air is moved in a minute, FPM measures how fast the air is moving. FPM is also a factor in determining the size of your system.

Understanding the main acronyms for HVAC terms can help when you are choosing a new system or an upgrade.

Why Choose A Service From High Mark Service Group

When you need service, you need it fixed fast and fixed properly. Highmark offers quick, affordable service as soon as possible. We are here for you!

  • Our technicians are the most experienced available
  • We offer a methodical approach so you do not have unneeded repairs
  • Fully stocked trucks
  • We do residential, commercial, and industrial asbestos service
  • Your satisfaction is our goal

We Are Here For You

If you have any questions call the professionals at Highmark Plumbing and we will be happy to answer them for you. For any heating, electrical, or home repair issues visit our sister websites Highmark Heating,  Highmark Electrical or Highmark Construction


Plumbing Diagnostics

Recent Posts







The information contained in https://highmarkplumbing.com  is for general information purposes only. The information is provided by https://highmarkplumbing.com  and while we endeavor to keep the information up to date and correct, we make no representations or warranties of any kind, express or implied, about the completeness, accuracy, reliability, suitability or availability with respect to https://highmarkplumbing.com   or the information, products, services, or related graphics contained on https://highmarkplumbing.com   for any purpose. Any reliance you place on such information is therefore strictly at your own risk.

In no event will we be liable for any loss or damage including without limitation, indirect or consequential loss or damage, or any loss or damage whatsoever arising from loss of data or profits arising out of, or in connection with, the use of https://highmarkplumbing.com.