Shopping for a new AC or furnace can be stressful. 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 equipment should deliver the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
Efficiency ratings aren’t the only thing you should consider 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 often even 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 delivers efficiency and proper sizing.
In this blog, 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 qualified HVAC contractors 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), measures how effectively a cooling system cools your home over a typical cooling season. A SEER2 rating is the updated version of SEER, using testing methods that better reflect real-world operating conditions. Most new air conditioners have a SEER2 efficiency rating, simply because that is the new rating system for cooling equipment.
Fuel-burning heating system efficiency is rated by AFUE, which stands for Annual Fuel Utilization Efficiency. Similar to 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. Real-world heating and air conditioner efficiency depends on several key factors, including the quality of the installation, the condition of your ductwork, your home's insulation, thermostat settings and, most importantly, system sizing. Even the most efficient system cannot deliver peak performance if it is oversized 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. Actually, new heating system installation or a new air conditioner should be sized 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 technicians perform an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many variables that affect your home's comfort needs, including:
- Overall square footage
- Ceiling height
- Window size and direction
- Home insultation levels
- Air leakage
- Local climate
- Household 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 even temperatures, better indoor comfort and improved moisture control. This also allows the equipment to perform more effciently, reducing strain that can reduce its service life or lead to frequent or expensive repairs.
When a furnace or AC is the right size for your home, you get improved comfort and more reliable operation.
Problems Caused by Oversized and Undersized HVAC Equipment
Many homeowners are tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. However, that’s rarely a smart choice.
heating and cooling systems that are too large or undersized can create comfort issues, 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 heat or cool rapidly, 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.
- Reduced humidity control: Oversized air conditioners cool your home too quickly to remove indoor humidity from the air.
- Hot and cold spots: Some rooms feel too cool while others aren’t ever cool enough.
- Increased wear and tear: Even though the system works quickly, those constant 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 desired temperature, which also causes unnecessary wear and tear.
- Difficulty maintaining the desired temperature: Your home may feel cool enough during hot weather or always feel chilly in the winter.
- Increased energy consumption: Running for extended periods can increase utility bills.
- Added strain during extreme weather: HVAC systems that are too small can run extremely hard in extreme temperatures, increasing component strain and the likelihood of repairs.
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 always need the most efficient model on the market.
In many cases, a correctly sized, mid-efficiency heating and cooling system will deliver better performance than an overly large premium system because it functions the way it was designed to.
Theideal choice is an energy-efficient HVAC system that's properly 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, keep these factors in mind:
- Efficiency savings: Higher-efficiency and right-sized systems can decrease 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.
- Energy prices: Areas with more expensive electricity may see greater long-term savings from higher-efficiency units.
- Seasonal weather conditions: It's important your heating or cooling system has the right capacity to handle areas with harsh winter weather 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 offset the investment.
- Available rebates or tax incentives: Manufacturer promotions, {utility|equipment rebates and tax credits can reduce the overall cost of high-efficiency HVAC equipment.
Real-World Example: High Seer vs. Right System Size
What does this look like in a real world example?
Imagine two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system that's too big because the contractor simply matched the previous unit. Next door, the second homeowner installs a properly sized, mid-efficiency system after completing a Manual J calculation.
While the second system has a lower efficiency rating on paper, it may provide lower operating costs, better home comfort, more effective humidity control and have a longer lifespan because it's correctly matched 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 highest efficiency rating. The best system is one that meets your home’s heating and cooling requirements.
At Walter's-Eaton's Electric, Plumbing, Heating & AC, our experienced professionals perform an HVAC load calculation. Our team will evaluate your home's layout and construction, your household's comfort needs and recommend equipment that's properly matched for your home—not simply the biggest, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts will let you know about any available rebates or tax incentives 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 Walter's-Eaton's Electric, Plumbing, Heating & AC now. We'll gladly 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.
