Choosing a new AC or furnace can be stressful. 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.
After all, the most efficient heating and cooling system will provide the most comfort and lowest energy bills, right?
It’s not quite that simple.
Energy efficiency isn't the only thing that matters when it comes to new air conditioner installation or furnace replacement. Even though many focus only on energy efficiency, proper HVAC system sizing is often even more important for your home's comfort and your utility bills.
Proper sizing directly impacts humidity control and long-term reliability. The best HVAC system for your home delivers energy efficiency and correct sizing.
In this article, we'll explain what an air conditioner's SEER rating or SEER2 rating actually measures, why proper HVAC system size is so important and why experienced HVAC professionals consider both when recommending the best HVAC system for your home.
High Seer Ratings: What Do They Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), indicates how efficiently a cooling system cools your home over a standard cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better simulate real-world operating conditions. Nearly all new air conditioners have a SEER2 rating, simply because this is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by an AFUE rating, which stands for Annual Fuel Utilization Efficiency. As with cooling efficiency ratings, 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 numbers don't automatically guarantee lower utility bills. Everyday heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the quality of your ductwork, insulation levels, thermostat settings and, most importantly, system sizing. Even the highest-rated system cannot perform as intended if it is too large or smaller than needed for the home.
Why HVAC System Size Matters More Than You Probably Think
Many assume a higher-capacity air conditioner or furnace will heat or cool a home better or that they should just replace their old HVAC system with a new one the same size. In reality, new heating system installation or a new air conditioner should be chosen 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 companies perform an HVAC load calculation, also called a Manual J calculation, before recommending replacement equipment. A Manual J calculation considers many details that affect your home's heating and cooling requirements, including:
- Overall square footage
- Ceiling height
- Window size and orientation
- Insulation
- Air infiltration
- Area climate
- Number of occupants
- Heat generated by appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home consistently while pulling out excess humidity. That means more even temperatures, better indoor comfort and improved moisture control. It also helps the equipment to perform more effciently, reducing strain that can cause it to wear it out sooner or lead to more repairs and higher repair costs.
When your heating or cooling system is the right size for your home, you get improved comfort and long-lasting performance.
Problems Caused by Oversized and Undersized Heating and Cooling Systems
You may be tempted to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. The truth is, that’s rarely a great idea.
heating and cooling systems that are too large or too small can create comfort problems, increase energy expenses and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may heat or cool rapidly, but that doesn't mean it delivers the best comfort.
- Short cycling: An oversized HVAC system cycles repeatedly, reducing efficiency and increasing wear.
- Poor humidity removal: Oversized air conditioners reach the set temperature too fast to remove excess moisture from the air.
- Inconsistent temperatures: Some rooms get too cold while others stay too warm.
- More wear and tear: Even though the system heats or cools your home fast, those constant cycles can cause avoidable breakdowns due to the strain.
Drawbacks of Undersized HVAC Systems
An undersized HVAC system can have the opposite problem:
- Continuous operation: The system stays on for extended periods trying to reach the set temperature, which also causes additional wear.
- Difficulty maintaining the desired temperature: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Higher energy use: Running for extended periods can increase utility bills.
- Extra stress during severe weather: HVAC systems that are too small can struggle in extreme temperatures, increasing equipment wear and the chance of failure.
Why You Should Balance HVAC System Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, remember that you don't automatically need the most efficient model on the market.
In many cases, a professionally sized, mid-efficiency heating and cooling system will provide better results than an overly large premium system because it operates the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's correctly sized for your home, your budget, your climate and your long-term goals.
As you think about how to choose a new air conditioner or furnace, consider:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease electricity use.
- Purchase price: High-efficiency AC and heating systems often require a larger upfront investment than mid-range models but can help reduce long-term energy costs.
- Electricity rates: Areas with higher electricity rates may see better long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's crucial your heating or cooling system has the right capacity to handle areas with very cold winters or extremely hot summers.
- Time you plan to own the home: If you intend to remain in your home for many years, the long-term energy savings of a higher-efficiency unit may justify the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of qualifying equipment.
Real-World Example: High Seer vs. Right System Size
How does this work in a real world example?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big for the house because the contractor only matched the previous unit. The other homeowner installs a properly sized, mid-SEER or AFUE system after completing a Manual J calculation.
While the second system has a more modest efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's appropriately sized to the home's needs.
Choose the HVAC Professional Who Designs the Right Solution
An HVAC replacement should involve more than selecting a system with the top efficiency rating. The right system is one that meets your household heating and cooling requirements.
At Jack's Heating, Cooling, Stoves & Fireplaces, our skilled HVAC experts perform an HVAC load calculation. Our team will evaluate your home's size and layout, your household's heating and cooling preferences and recommend equipment that's properly matched for your home—not simply the highest-capacity, most expensive unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will help you identify 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 Jack's Heating, Cooling, Stoves & Fireplaces to get started. Our team will evaluate your home, answer your questions and help you choose the right-sized high-efficiency system that keeps your family comfortable for the long haul.