Choosing a new AC or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's common to look for models with the highest efficiency ratings.
After all, the most efficient equipment will provide the most comfort and lowest energy bills, right?
It’s not quite that simple.
Efficiency ratings aren’t the only thing you should consider when it comes to new air conditioner installation or installing a new furnace. Even though many focus only on efficiency ratings, proper HVAC system sizing is just as, if not more important for your home's comfort and your energy bills.
Proper sizing directly impacts humidity control and system longevity. The best HVAC system for your home combines efficiency and proper sizing.
In this article, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system sizing is so important and why experienced HVAC professionals consider both when recommending the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), measures how efficiently an AC cools your home over a normal cooling season. A SEER2 rating is the newer version of SEER, using test procedures that better represent real-world operating conditions. Today’s new air conditioners have a SEER2 rating, simply because this rating is the updated rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by something called AFUE, which is short for Annual Fuel Utilization Efficiency. As with cooling efficiency ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to keep you comfortable than lower-rated systems under standardized laboratory testing.
That said, high numbers don't necessarily guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on many factors, including the installation quality, the state of your ductwork, your home's insulation, thermostat settings and, most importantly, system sizing. Even the most efficient system cannot operate at its best if it is oversized or undersized for the home.
Why Proper HVAC Sizing Matters More Than Most Homeowners Realize
Many assume a larger air conditioner or furnace will work the best or that they should simply replace their old HVAC system with a unit of the same capacity. In reality, new heating system installation or air conditioner replacement should be chosen based on your home's actual heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable contractors perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation considers many variables that affect your home's heating and cooling requirements, including:
- Home square footage
- Room height
- Window size and placement
- Insulation
- Drafts and air leakage
- Local climate
- Household occupants
- Heat generated by appliances and lighting
- Air duct condition
A properly sized air conditioner runs long enough to cool your home evenly while eliminating excess humidity. That means steadier temperatures, better indoor comfort and improved humidity control. Proper sizing also helps the equipment to run more effciently, reducing strain that can shorten its lifespan or lead to costly breakdowns.
When HVAC equipment is the right size for your home, you get greater comfort and more dependable performance.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
It might be tempting to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that often isn't a smart choice.
HVAC systems that are too large or undersized can create comfort problems, increase energy expenses and reduce efficiency regardless of their SEER rating.
Issues Created by Oversized HVAC Systems
An oversized air conditioner or heating system may reach the thermostat setting fast, but that doesn't mean it works well.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing equipment strain.
- Poor humidity removal: Oversized air conditioners finish cooling cycles too soon to remove indoor humidity from the air.
- Inconsistent temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Increased wear and tear: Even though the system works quickly, those repeated on-and-off cycles can cause avoidable breakdowns due to the strain.
Issues Created by Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Long run times: The system stays on for extended periods trying to reach the set temperature, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may not feel comfortable during hot weather or feel too cool during winter.
- Higher energy use: Running nonstop can increase energy costs.
- Greater strain on very hot or cold days: HVAC systems that are too small can work harder in extreme temperatures, increasing equipment wear and the chance of failure.
Finding the Right Balance Between Efficiency and Size
When trying to decide between a high SEER vs right-sized system, don't forget that you don't necessarily need the highest-efficiency model on the market.
More often than not, a correctly sized, mid-efficiency HVAC system will outperform an overly large premium system because it operates the way it was designed to.
Thesmartest choice is an energy-efficient HVAC system that's correctly sized for your home, your budget, your climate and your future plans.
As you consider how to choose a new air conditioner or furnace, think about:
- Lower energy costs: Higher-efficiency and right-sized systems can reduce electricity use.
- Upfront investment: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can lower long-term energy costs.
- Local utility costs: Areas with higher utility costs may see more significant long-term savings from higher-efficiency units.
- Climate: It's crucial your heating or cooling system has enough capacity to handle areas with very cold winters or very hot summers.
- Length of home ownership: If you plan to stay in your home for many years, the long-term energy savings of a higher-efficiency unit may justify the investment.
- Financial incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of high-efficiency HVAC equipment.
Real-World Situation: High Seer vs. Right System Size
How does this play out in a real world example?
Suppose there are two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor replaced it with the same size system as the previous unit. Next door, the second homeowner installs a right-sized, moderate-efficiency system after completing a Manual J calculation.
Although the second system has a more modest efficiency rating on paper, it may deliver lower operating costs, better home comfort, improved humidity control and last longer because it's correctly matched to the home's needs.
Work With an HVAC Professional Who Designs Solutions Tailored to Your Home
HVAC replacent or installation should involve much more than selecting a model with the top efficiency rating. The right system is one that meets your household heating and cooling requirements.
At ACE Solutions, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's design, your household's heating and cooling preferences and recommend equipment that's right for your home—not simply the largest, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will let you know about any available tax rebates and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with ACE Solutions now. We'll gladly evaluate your home, answer any questions and help you choose the properly sized energy-efficient system that keeps your family comfortable for many years.