Overview

One of the terms an HVAC contractor is likely to bring up during an installation is efficiency. It’s certainly one that Greg's Comfort Control Systems pays close attention to when servicing heating and cooling systems. Efficiency reflects how much energy your system needs to produce the comfort you expect, and that can change as problems develop and standards and technologies evolve. In this blog post, we look at what causes HVAC systems to lose efficiency and when declining performance may factor into replacement.

Introduction

Efficiency and environmental impact are such important qualities that equipment is subject to federal standards. This can sound like a concern that belongs exclusively to equipment manufacturers and regulators, far removed from your day-to-day experience. In reality, efficiency has a direct bearing on your comfort and what you’re spending to sustain it.

Efficiency is also worth protecting, because a high-rated system doesn’t guarantee high-efficiency operation forever. As problems develop, the system can require more energy to accomplish the same job, sometimes well before anything stops working altogether. A proactive approach to maintenance and help from your technicians can go a long way toward preserving your comfort.

How Is HVAC Efficiency Measured?

There are actually multiple ways to measure HVAC efficiency. SEER2 tends to be the most recognizable because it’s commonly used when comparing central air conditioners and heat pumps. However, it’s not the only one that matters and it’s worth understanding a few of the other rating systems.

The following are all the ways efficiency is normally measured:

SEER2 (Seasonal Energy Efficiency Ratio 2): Measures how efficiently an air conditioner or heat pump provides cooling over an entire cooling season. A higher rating indicates greater efficiency.
EER2 (Energy Efficiency Ratio 2): Measures cooling efficiency under specific testing conditions, at peak load. A higher EER2 indicates more efficient operation under those conditions.
HSPF2 (Heating Seasonal Performance Factor 2): Measures how efficiently a heat pump provides heating over the course of a season. Higher ratings indicate greater heating efficiency.
AFUE (Annual Fuel Utilization Efficiency): Measures how efficiently a furnace converts fuel into usable heat. It’s expressed as a percentage, so a 95% AFUE furnace converts approximately 95% of the fuel’s energy into heat.

Another rating is BTU or BTU/h, which measures heating or cooling capacity, not efficiency. The difference, in simple terms, is that efficiency tells you how effectively the system uses energy, while BTU/h tells you how much heating or cooling it can actually produce. So, a higher-capacity system isn’t necessarily a more efficient one. It still makes sense to consider, along with the other metrics, though.

Why Does HVAC Efficiency Rating Matter?

A more efficient HVAC system sounds like a no-brainer. If two systems can keep your property comfortable, why wouldn’t you want the one that can do the job using less energy?

That difference has practical consequences once the equipment is running on your property. Greater efficiency means more of the energy you’re paying for goes toward useful heating or cooling instead of being lost in the process. Over years of operation, the resulting energy savings are where those efficiency ratings begin to have real financial value. Plus, newer, more efficient systems often come with benefits such as better humidity control during cooling, and less noticeable temperature fluctuation.

Identifying Heating and Cooling Efficiency Problems

Maintaining efficiency means recognizing that your system may not always operate at the level that the rating suggests. Problems can develop that interfere with heating and cooling performance, so identifying them early helps you avoid losing efficiency unnecessarily. Remember, ratings are also established under standardized testing. In actual use, the conditions aren’t always one-to-one.

Below are some of the most common problems that hurt efficiency.

Dirty HVAC Filters Restrict Airflow

Your HVAC filter collects airborne particles as return air passes through it. Over time, those particles build up across the filter material, leaving less open space for air to pass through. The longer a loaded filter stays in place, the more resistance it can create within the airflow path.

That resistance makes the system work harder to move the air needed for heating or cooling, increasing the energy required to do the same job. The simplest way to avoid that loss is to replace the filter at the appropriate interval instead of waiting until airflow has already suffered. If you do this yourself, make sure the replacement matches the size and filter specifications recommended for your system. You can also just have your technician replace it during routine maintenance.

Dirty Evaporator and Condenser Coils Reduce Heat Transfer

Your evaporator and condenser coils handle the transfer of heat that makes air conditioning possible. The indoor evaporator coil can collect dust and other particles carried through the system, especially when, as discussed above, filtration is poor. Outside, the condenser coil is exposed