Choosing a new air conditioner or furnace can be stressful. When you're looking to find the best HVAC system for your home, it's understandable to look for models with extremely high efficiency ratings.
Surely the most efficient heating and cooling system provides the most comfort and lowest energy bills, right?
Actually, that’s not always the case.
High efficiency isn't the only thing to think about when it comes to new air conditioner installation or replacing your furnace. Although many people focus only on energy efficiency, proper HVAC system sizing is equally, if not more important for your home's comfort and your energy bills.
Proper sizing directly impacts humidity control and long-term reliability. The best HVAC system for your home balances 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 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 effectively a cooling system cools your home over a typical cooling season. A SEER2 rating is the newer version of SEER, using evaluation methods that better reflect real-world operating conditions. Most new air conditioners have a SEER2 efficiency rating, simply because this rating is the current rating system for cooling equipment.
Fuel-burning heating system efficiency is measured by something called AFUE, which stands for Annual Fuel Utilization Efficiency. As with SEER and SEER2 ratings, higher AFUE ratings indicate a high-efficiency HVAC system that uses less electricity to heat your home than lower-rated systems under standardized laboratory testing.
However, high numbers don't necessarily guarantee lower utility bills. Real-world heating and air conditioner efficiency depends on more than just efficiency ratings, including the way the system is installed, the quality of your ductwork, your home's insulation, thermostat settings and, most importantly, HVAC system sizing. Even the highest-efficiency system cannot perform as intended if it is bigger than necessary or smaller than needed for the home.
Why HVAC System Size Matters More Than You Think
Many assume a larger air conditioner or furnace will work the best or that they should simply replace their old HVAC system with a same-sized replacement. The truth is, 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 capacity of the old system.
That's why reputable contractors conduct an HVAC load calculation, also called a Manual J calculation, before selecting replacement equipment. A Manual J calculation analyzes many variables that impact your home's heating and cooling requirements, including:
- Overall square footage
- Room height
- Window size and placement
- Insulation
- Air leakage
- Local climate
- Household occupants
- Heat produced from appliances and lighting
- Ductwork condition
A properly sized air conditioner runs through longer cooling cycles to cool your home evenly while removing excess humidity. That means more consistent temperatures, better indoor comfort and improved humidity control. Proper sizing also helps the equipment to run more effciently, reducing excessive wear and tear that can shorten its lifespan or lead to frequent or expensive repairs.
When HVAC equipment is correctly sized, you get greater comfort and long-lasting performance.
Problems with Oversized and Undersized Heating and Cooling Systems
You may be tempted to buy the most energy efficient, biggest air conditioner or heating system on the market. The truth is, that's usually not a great idea.
HVAC systems that are too large or too small can create comfort issues, increase operating costs and reduce efficiency regardless of their SEER rating.
Common Problems With Oversized HVAC Systems
An oversized air conditioner or heating system may work quickly, but that doesn't mean it works well.
- Short cycling: An oversized HVAC system turns on and off frequently, reducing efficiency and increasing equipment strain.
- Humidity problems: Oversized air conditioners reach the set temperature too fast to remove indoor humidity from the air.
- Hot and cold spots: Some rooms get too cold while others aren’t ever cool enough.
- 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 has a different set of problems:
- Continuous operation: The system runs for long periods trying to reach the desired temperature, which also causes unnecessary wear and tear.
- Trouble reaching the thermostat setting: Your home may never feel as cool as you want during hot weather or always feel chilly in the winter.
- Greater energy usage: Running for extended periods can increase utility bills.
- Extra stress during severe weather: HVAC systems that are too small can run extremely hard 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, remember 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 oversized premium system because it functions the way it was designed to.
Thebest choice is an energy-efficient HVAC system that's matched 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 decrease electricity use.
- Initial cost: 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.
- Climate: It's important your heating or cooling system has the right capacity to handle areas with very cold winters or extremely 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 be worth the investment.
- Rebates and tax credits: Manufacturer promotions, {utility|equipment rebates and tax credits can offset the overall cost of higher-efficiency systems.
Real-World Example: High Seer vs. Right System Size
How does this play out in a real world scenario?
Suppose there are two neighboring homes.
In the first, the homeowner chooses a premium high-efficiency HVAC system has far more capacity than the home needs because the contractor simply matched the previous unit. The other homeowner installs a right-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, improved humidity control and last longer because it's appropriately sized to the home's needs.
Work With an HVAC Professional Who Designs the Right Solution
HVAC replacent or installation should involve more than selecting the unit with the top efficiency rating. The right system is one that meets your home’s heating and cooling requirements.
At Watts Electric & AC, our knowledgeable technicians perform an HVAC load calculation. Our team will evaluate your home's design, your household's comfort goals and recommend equipment that's right for your home—not simply the highest-capacity, fanciest unit or the one with the highest AFUE or SEER2 rating.
Our HVAC experts 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 Watts Electric & AC to get started. Our team will evaluate your home, answer any questions and help you choose the right-sized energy-efficient system that keeps your family comfortable for years to come.