Choosing a new air conditioner or furnace can be intimidating. When you're looking to find the best HVAC system for your home, it's natural to look for models with extremely high efficiency ratings.
After all, the most efficient heating and cooling system will provide the most comfort and lowest energy bills, right?
Not necessarily.
High efficiency isn't the only thing that matters when it comes to new air conditioner installation or replacing your 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 has a major impact on humidity control and long-term reliability. The best HVAC system for your home delivers 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 experienced HVAC professionals consider both when helping you choose the best HVAC system for your home.
What Does a High SEER Rating Actually Mean?
A SEER rating, (Seasonal Energy Efficiency Ratio), shows how efficiently a cooling system cools your home over a typical cooling season. A SEER2 rating is the current version of SEER, using testing methods that better represent 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 measured by an AFUE rating, which is for Annual Fuel Utilization Efficiency. Like SEER and SEER2 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.
Even so, high ratings don't by themselves guarantee lower utility bills. Actual heating and air conditioner efficiency depends on more than just efficiency ratings, including the quality of the installation, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, proper HVAC system sizing. Even the most efficient system cannot deliver peak performance if it is too large or undersized for the home.
Why Correct HVAC System Sizing Matters More Than You Probably Think
Many assume a larger air conditioner or furnace will work the best or that they should just replace their old HVAC system with a unit of the same capacity. The truth is, new heating system installation or a new air conditioner should be chosen based on your home's true heating and cooling needs—not just square footage or the size of the previous unit.
That's why reputable companies perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation considers many variables that impact your home's comfort needs, including:
- Total square footage
- Ceiling height
- Window size and orientation
- Insulation
- Air leakage
- Local climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs for enough time to cool your home evenly while eliminating excess humidity. That means steadier temperatures, better indoor comfort and improved humidity control. It also helps the equipment to perform more effciently, reducing unnecessary wear that can reduce its service life or lead to frequent or expensive repairs.
When HVAC equipment is correctly sized, you get improved comfort and more dependable performance.
Problems Caused by Oversized and Undersized HVAC Equipment
It might be tempting to buy the most energy efficient, highest-capacity air conditioner or heating system on the market. In reality, that’s rarely a good investment.
HVAC systems that are too large or too small can create comfort issues, increase utility costs and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may reach the thermostat setting fast, but that doesn't mean it performs efficiently.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing wear and tear.
- High indoor humidity: Oversized air conditioners reach the set temperature too fast to remove enough moisture from the air.
- Inconsistent temperatures: Some rooms feel too cool while others aren’t ever cool enough.
- Additional equipment wear: Even though the system works quickly, those repeated on-and-off 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 desired temperature, which also causes additional wear.
- Difficulty reaching thermostat settings: Your home may never feel as cool as you want during hot weather or feel too cool during winter.
- Greater energy usage: Running almost constantly can increase monthly energy expenses.
- Added strain during extreme weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing equipment wear and the risk of breakdowns.
Finding the Right Balance Between Efficiency and Size
When weighing the pros and cons of a high SEER vs right-sized system, don't forget that you don't necessarily need the top-efficiency model on the market.
In many cases, a properly sized, mid-efficiency heating and cooling system will deliver better performance than an overly large premium system because it runs 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 future plans.
As you think about how to choose a new air conditioner or furnace, think about:
- Energy savings: Higher-efficiency and right-sized systems can reduce electricity use.
- Upfront investment: High-efficiency AC and heating systems often cost more initially than mid-range models but can reduce long-term energy costs.
- Electricity rates: Areas with more expensive electricity may see greater long-term savings from higher-efficiency units.
- Climate: It's important your heating or cooling system has adequate capacity to handle areas with extremely cold winters or very hot summers.
- Time you plan to own the home: If you expect to live in your home for many years, the long-term energy savings of a higher-efficiency unit may offset the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can lower the overall cost of high-efficiency HVAC equipment.
Real-World Comparison: High Seer vs. Right System Size
How does this play out 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 because the contractor only matched the previous unit. At the neighboring home, an HVAC professional installs a right-sized, mid-SEER or AFUE system after completing a Manual J calculation.
While the second system has a lesser efficiency rating on paper, it may deliver lower operating costs, better home comfort, more effective humidity control and last longer because it's properly matched to the home's needs.
Choose the HVAC Professional Who Designs Solutions Tailored to Your Home
HVAC replacent or installation should involve more than selecting the unit with the highest efficiency rating. The right system is one that meets your household heating and cooling requirements.
At MPC Heating & Cooling, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's layout and construction, your household's heating and cooling preferences and recommend equipment that's properly matched for your home—not simply the highest-capacity, latest and greatest unit or the one with the highest AFUE or SEER2 rating.
Our heating and cooling specialists will connect you with any available rebates or tax incentives and provide information about HVAC financing options that make high-efficiency systems more accessible for all budgets.
Schedule an HVAC consultation online with MPC Heating & Cooling now. Our team will evaluate your home, answer your questions and help you choose the right-sized efficient system that keeps your family comfortable for years to come.