Choosing a new air conditioning system or furnace can be intimidating. If you're trying to find the best HVAC system for your home, it's understandable to focus on models with the highest efficiency ratings.
Surely the most efficient heating and cooling system will provide the most comfort and lowest energy bills, right?
Not necessarily.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or installing a new furnace. While many homeowners focus only on efficiency ratings, proper HVAC system sizing is equally, if not more important for your home's comfort and your power bills.
Proper sizing directly impacts humidity control and lasting performance. The best HVAC system for your home combines energy efficiency and proper sizing.
In this article, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why correct HVAC size is so important and why trusted HVAC experts consider both when helping you select the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how effectively an air conditioner cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using test procedures that better simulate real-world operating conditions. Most new air conditioners have a SEER2 rating, simply because that is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by something called AFUE, which is short for Annual Fuel Utilization Efficiency. Like SEER and SEER2, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to achieve indoor comfort than lower-rated systems under standardized laboratory testing.
That said, high ratings don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on several key factors, including the way the system is installed, the state of your ductwork, insulation levels, thermostat settings and, most importantly, HVAC system sizing. Even the highest-efficiency system cannot perform as intended if it is bigger than necessary or undersized for the home.
Why Correct HVAC System Sizing Matters More Than Most Homeowners Realize
Many assume a larger air conditioner or furnace will make their home the most comfortable or that they should just replace their old HVAC system with a unit of the same capacity. In reality, new heating system installation or AC replacement should be sized based on your home's actual heating and cooling needs—not just square footage or the size of your existing equipment.
That's why reputable technicians conduct an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation analyzes many details that impact your home's heating and cooling requirements, including:
- Home square footage
- Room height
- Window size and direction
- Home insultation levels
- Drafts and air leakage
- Regional climate
- Number of occupants
- Heat produced from appliances and lighting
- Air duct condition
A properly sized air conditioner runs for enough time to cool your home evenly while removing excess humidity. That means more consistent temperatures, better indoor comfort and improved indoor humidity management. It also helps the equipment to run more effciently, reducing excessive wear and tear that can reduce its service life or lead to more repairs and higher repair costs.
When your heating or cooling system is properly sized, you get improved comfort and more dependable performance.
Problems Caused by Oversized and Undersized Systems
You may be tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. However, that's usually not a great idea.
HVAC systems that are bigger than your home needs or too small can create indoor comfort challenges, increase operating costs 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 turns on and off frequently, reducing efficiency and increasing wear and tear.
- High indoor humidity: Oversized air conditioners finish cooling cycles too soon to remove indoor humidity from the air.
- Inconsistent temperatures: Some rooms become too cold while others never feel comfortable.
- More wear and tear: Even though the system works quickly, those constant cycles can cause avoidable breakdowns due to the strain.
Cons Associated with Undersized HVAC Systems
An undersized HVAC system has a different set of problems:
- 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 never feel as cool as you want during hot weather or always feel chilly in the winter.
- Greater energy usage: Running almost constantly can increase energy costs.
- Extra stress during severe weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing component strain and the likelihood of repairs.
Balancing Efficiency and Size
When trying to decide between a high SEER vs right-sized system, remember that you don't necessarily need the top-efficiency model on the market.
More often than not, a correctly sized, mid-efficiency HVAC system will deliver better performance than an overly large premium system because it runs the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's properly sized for your home, your budget, your climate and your long-term goals.
When deciding how to choose a new air conditioner or furnace, keep these factors in mind:
- Lower energy costs: Higher-efficiency and right-sized systems can lower electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can help reduce long-term energy costs.
- Local utility costs: Areas with higher utility costs may see better long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's crucial your heating or cooling system has adequate capacity to handle areas with harsh winter weather or very hot summers.
- How long you'll own the home: If you plan to stay in your home for many years, the long-term energy savings of a higher-efficiency unit may be worth the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of qualifying equipment.
Real-World Comparison: High Seer vs. Right System Size
What does this look like in a real world example?
Imagine two neighboring homes.
In one, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor replaced it with the same size system as the previous unit. The other homeowner installs a right-sized, mid-efficiency system after completing a Manual J calculation.
Even though the second system has a lesser efficiency rating on paper, it may provide lower operating costs, better home comfort, improved humidity control and have a longer lifespan because it's appropriately sized to the home's needs.
Work With an HVAC Professional Who Designs Solutions Tailored to Your Home
An HVAC replacement should involve more than selecting a model with the highest efficiency rating. An ideal system is one that meets your home’s heating and cooling requirements.
At Kelly Heating & Air Conditioning, our skilled HVAC experts perform an HVAC load calculation. We'll evaluate your home's design, your household's comfort needs and recommend equipment that's designed specifically for your home—not simply the biggest, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will connect you with any available tax rebates and provide information about HVAC financing options that make efficient heating and cooling systems more accessible for all budgets.
Schedule an HVAC consultation online with Kelly Heating & Air Conditioning now. We'll evaluate your home, answer any questions and help you choose the right-sized high-efficiency system that keeps your family comfortable for the long haul.
