Look it up, feel confident
HVAC Dictionary
A plain‑English guide to common heating, cooling, and ventilation terms
HVAC has a language of its own. One technician says “AFUE,” another says “air handler,” and suddenly you’re trying to make a comfort decision with a head full of acronyms.
We built this HVAC Dictionary to make the jargon feel simple. Use it when you’re comparing equipment, reading an estimate, researching efficiency, or just trying to understand what’s going on in your home or business.
We’ve been servicing the Reno–Sparks and surrounding areas since 1991, and we specialize in residential and light commercial heating, air conditioning, and ventilation—everything from building from the ground up and retrofits to repairs, service, and preventative maintenance of all HVAC equipment. When you understand the words, it’s easier to understand your options.
How to use this dictionary (and why it helps)
If you’re here to “just look up a term,” you’re in the right place. But this page can do more than definitions.
- For repairs: Knowing basic parts and measurements helps you describe symptoms clearly.
- For efficiency/green decisions: Understanding ratings and energy terms helps you compare systems apples-to-apples.
- For maintenance: Many comfort issues start with airflow, filtration, or simple components—terms you’ll see in checklists and recommendations.
If you can’t find a term you heard (or you want a plain explanation of what it means for your specific system), contact us and tell us the word you’re stuck on. We’re happy to translate.
Common words, explained
HVAC terms & definitions
Below are common HVAC terms you’ll see when researching heating and cooling. We’ll keep adding to this resource over time.
AFUE (Annual Fuel Utilization Efficiency)
Indicated as a percentage, your furnace's AFUE tells you how much energy is being converted to heat.
For example, an AFUE of 90 means that 90% of the fuel is being used to warm your home, while the other 10% escapes as exhaust with the combustion gases.
Why it matters: AFUE helps you compare heating efficiency. Higher percentages generally mean more of what you pay for becomes usable heat.
Advanced Reciprocating Compressor
Type of compressor that uses a more efficient process for compressing refrigerant for better cooling efficiency.
Why it matters: The compressor is a major player in cooling performance and energy use. Compressor design can affect efficiency and comfort.
Air Cleaner
A device that removes allergens, pollutants and other undesirable particles from air that is heated or cooled.
Why it matters: Air cleaning is about more than dust. It can improve how your home feels and how clean your system stays over time.
Air Handler
The portion of your air conditioner or heating system that forces air through your home's ductwork.
Why it matters: Even with great equipment, comfort suffers if air isn’t moved properly. Air handlers are central to airflow and distribution.
BTU (British Thermal Unit)
British Thermal Unit.
Used for both heating and cooling, BTU is a measure of the heat given off when fuel is combusted.
Why it matters: BTUs come up when talking about system capacity. Understanding the term helps you follow conversations about sizing and output.
Ratings that actually matter
Efficiency terms: what to pay attention to
A lot of “green” HVAC talk boils down to two questions:
- How efficiently does the system turn energy into comfort? (That’s where ratings like AFUE come in.)
- How well does the comfort actually get delivered through the home or building? (That’s where airflow terms like air handler—and the condition of the system overall—matter.)
Efficiency isn’t just a number on paper. Real-world comfort depends on the full system working together.
When a definition isn’t enough
Sometimes the word isn’t the real problem—the real problem is what it implies. If you’re reading a diagnosis or researching an upgrade, you may be wondering:
- “Is this part a big deal or a simple fix?”
- “Does this term affect efficiency, comfort, or both?”
- “Is this about air quality, airflow, or equipment performance?”
If you want help connecting the dots, we can walk through what you’re seeing and what it typically means for repairs, service, or preventative maintenance.
Want help from a local HVAC team?
If you’re in the Reno–Sparks area or nearby and you’d like a professional opinion, reach out to Weakland’s Heating & Air Conditioning, Inc. We specialize in residential and light commercial heating, air conditioning, and ventilation—new builds, retrofits, repairs, service, and preventative maintenance.
Bring us the term you found here (or the one you can’t find). We’ll help you turn HVAC language into a clear next step.