About - SEER Calculator

SEER Calculator is a free online tool designed to help homeowners, HVAC professionals, and anyone researching air conditioning efficiency make informed decisions about cooling systems. Our calculators use industry-standard formulas to estimate energy consumption, operating costs, and potential savings.

What This Calculator Does

Our calculator suite includes four specialized tools, each designed to answer specific questions about air conditioner efficiency and operating costs:

Savings Calculator

The Savings Calculator estimates how much money you could save annually by upgrading from an older, less efficient air conditioner to a newer, higher-SEER unit. You input your current SEER rating, the new SEER rating you're considering, your AC unit size in tons, annual cooling hours based on your climate zone, and your local electricity rate. The calculator then shows your projected annual savings in dollars, monthly savings, 10-year cumulative savings, kilowatt-hours saved, percentage reduction in energy use, and payback period if you enter the upgrade cost. Visual comparison bars help you see the difference in energy consumption between your current and potential new system.

Compare Calculator

The Compare Calculator lets you evaluate two different SEER ratings side-by-side to see exactly how their operating costs differ. This is useful when you're choosing between two AC units at different price points and efficiency levels. Enter any two SEER ratings along with unit size, cooling hours, and electricity rate to see the annual cost for each option and the dollar difference between them.

EER to SEER Converter

The EER-SEER Converter translates between these two common efficiency ratings. EER (Energy Efficiency Ratio) measures efficiency at a single test condition (95°F outdoor temperature), while SEER (Seasonal Energy Efficiency Ratio) represents average efficiency across a range of seasonal temperatures. Both ratings are tested and certified through the Air-Conditioning, Heating, and Refrigeration Institute (AHRI). Some manufacturers list only one rating, so this converter helps you compare units that use different metrics.

Cost Calculator

The Cost Calculator estimates your annual cooling costs based on your specific usage patterns. Rather than using annual cooling hours, this calculator lets you input hours of AC operation per day and months of cooling season, making it easier to estimate if you know your daily usage but not your total annual hours. It also compares your system's cost to a baseline 14 SEER unit (the current federal minimum in most regions).

The Science Behind It

SEER stands for Seasonal Energy Efficiency Ratio, a metric established by the U.S. Department of Energy and used throughout the HVAC industry. It represents the total cooling output (measured in BTUs) divided by the total electrical energy input (measured in watt-hours) over a typical cooling season.

The fundamental principle is straightforward: a higher SEER rating means more cooling per unit of electricity consumed. A 20 SEER air conditioner produces the same amount of cooling as a 10 SEER unit while using half the electricity. Upgrading to a high-efficiency unit may also qualify for ENERGY STAR certification, which signals top-tier energy performance.

Core Formula

Our calculators use the standard formula for estimating annual energy consumption of an air conditioning system:

Annual kWh = (BTU/hour × Annual Cooling Hours) ÷ (SEER × 1,000)

Where:

BTU/hour is the cooling capacity (1 ton = 12,000 BTU/hour)
Annual Cooling Hours varies by climate (typically 600-2,500 hours)
SEER is the efficiency rating of the unit
1,000 converts watt-hours to kilowatt-hours

Annual cost is then calculated by multiplying the kWh by your electricity rate ($/kWh).

EER-SEER Conversion

For converting between EER and SEER, we use the widely-accepted approximation established by AHRI:

SEER ≈ EER × 1.12

This relationship exists because SEER testing includes periods of lower outdoor temperatures where the system operates more efficiently, resulting in a higher seasonal average than the single-point EER measurement at 95°F.

Who This Is For

SEER Calculator serves several audiences:

Homeowners considering AC replacement who want to understand whether a higher-efficiency unit justifies its higher price tag
Home buyers evaluating properties with different HVAC systems and wanting to estimate operating costs
HVAC professionals who need quick calculations to help customers compare options
Energy auditors estimating potential savings from equipment upgrades
Renters trying to estimate cooling costs in a new apartment
Students and researchers learning about HVAC efficiency metrics

Whether you're making a major purchase decision or simply curious about how much your AC costs to run, these tools provide quick, easy-to-understand estimates.

Our Methodology

The calculations used in SEER Calculator are based on standard HVAC industry formulas that reflect how air conditioning efficiency is measured and reported.

Climate Zone Data

We provide four climate zone presets based on typical annual cooling hours for different U.S. regions:

Hot climates (Arizona, Texas, Florida): ~2,500 cooling hours/year
Warm climates (Georgia, North Carolina, Tennessee): ~1,800 cooling hours/year
Moderate climates (Illinois, Ohio, Pennsylvania): ~1,200 cooling hours/year
Mild climates (Washington, Oregon, coastal California): ~600 cooling hours/year

These figures represent typical residential cooling loads and are consistent with data used by energy efficiency programs and utilities. You can always override these defaults with your own estimate based on local conditions and personal usage patterns.

Electricity Rate Default

We default to $0.15 per kWh, which approximates the U.S. national average residential electricity rate. However, rates vary significantly by region (from under $0.10 in some areas to over $0.30 in others), so we strongly recommend entering your actual rate from a recent utility bill for accurate results.

Payback Calculation

The payback period is calculated using simple payback: upgrade cost divided by annual savings. This straightforward method doesn't account for factors like inflation, rising electricity rates, or the time value of money, but it provides a useful baseline for comparison.

Our Data Sources

Transparency is important to us. Here is where the data and standards behind our calculator come from:

Climate zone data is based on ASHRAE climate zones and DOE regional data, which define typical cooling loads for different parts of the United States.
Electricity rates use the national average residential rate published by the U.S. Energy Information Administration (EIA) as our default value.
SEER testing standards follow AHRI Standard 210/240, which defines how air conditioner efficiency is measured and rated across the industry.
Minimum efficiency requirements are based on federal regulations set by the U.S. Department of Energy (DOE), which establishes SEER minimums by region.
Tax credit information is based on provisions from the Inflation Reduction Act (IRA) and DOE guidance. See Clean Energy Tax Credits for Consumers for current details.

Methodology Transparency

The following table summarizes the key default values used in our calculators and their sources:

Input	Default Value	Source
Electricity Rate	$0.15/kWh	EIA national average
Hot Climate Hours	2,500 hrs	DOE regional data
Warm Climate Hours	1,800 hrs	DOE regional data
Moderate Climate Hours	1,200 hrs	DOE regional data
Mild Climate Hours	600 hrs	DOE regional data
BTU per Ton	12,000	Industry standard
EER to SEER factor	1.12	AHRI approximation

All default values can be overridden with your own data for more accurate, personalized results. For a deeper understanding of how these values are used, see our Savings Calculator Guide, SEER Rating Chart, and HVAC Efficiency Calculator Guide.

Limitations & Disclaimer

These calculators provide estimates only. Actual energy consumption and savings depend on many factors not captured in these simplified calculations:

Installation quality: Improper installation can reduce actual efficiency by 20% or more
Duct system condition: Leaky or poorly insulated ducts significantly increase energy use
Home characteristics: Insulation levels, window efficiency, air sealing, and home orientation all affect cooling loads
Thermostat settings: Temperature setpoints and programming patterns impact runtime
Maintenance: Dirty filters, low refrigerant, and other issues reduce efficiency over time
Actual weather: Year-to-year temperature variations affect cooling needs
System sizing: Oversized or undersized equipment operates less efficiently

This tool is not a substitute for professional advice. For major HVAC decisions, we recommend:

Getting multiple quotes from licensed HVAC contractors
Having a professional perform a load calculation (Manual J) for proper sizing
Considering a home energy audit to identify the most cost-effective improvements
Checking with your utility for rebates and incentive programs

The information provided by SEER Calculator is for educational and estimation purposes only. We make no warranties about the accuracy of results for any specific situation.

How to Use the Calculator

Savings Calculator - Step by Step

Select your current SEER rating from the dropdown. If you don't know it, check the yellow EnergyGuide label on your outdoor unit, or estimate based on age (pre-2006 units are typically 10 SEER or less).
Select the new SEER rating you're considering.
Choose your AC unit size in tons. Common residential sizes are 2-5 tons. If unsure, a 3-ton unit is typical for a 1,500-2,000 sq ft home.
Select your climate zone to auto-fill typical cooling hours, or enter custom hours if you know your usage.
Enter your electricity rate from your utility bill (look for $/kWh).
Optionally enter the upgrade cost to see your payback period.
Click Calculate Savings to see results.

Compare Calculator - Step by Step

Enter the two SEER ratings you want to compare (e.g., 14 and 20).
Select your unit size and enter cooling hours.
Enter your electricity rate.
Click Compare SEER Ratings to see annual costs for each and the difference.

EER-SEER Converter - Step by Step

Select whether you're converting EER to SEER or SEER to EER.
Enter the value you want to convert.
Click Convert to see the equivalent rating.

Cost Calculator - Step by Step

Enter the SEER rating of your system.
Select your unit size.
Enter hours per day your AC typically runs during cooling season.
Enter the number of months you use air conditioning.
Enter your electricity rate.
Click Calculate Cost to see annual and monthly cooling costs.

Why We Built This

We created SEER Calculator to provide a genuinely useful, no-nonsense tool for understanding air conditioning efficiency. Here's what makes it different:

Completely free: No paywalls, no premium features, no limits on calculations.
No signup required: Use the calculator immediately without creating an account or providing an email address.
Privacy-focused: All calculations happen entirely in your browser using JavaScript. We don't send your inputs to any server, don't store your data, and don't track your calculations.
No ads or affiliate links: We don't promote specific brands or earn commissions on HVAC equipment.
Mobile-friendly: Works on phones, tablets, and desktops.
Open methodology: We explain exactly how the calculations work so you can verify them yourself.

Understanding SEER ratings and energy costs shouldn't require wading through sales pitches or handing over personal information. This calculator exists to give you straightforward answers to straightforward questions about AC efficiency.

Trusted Industry Resources

We recommend these authoritative sources for further research on HVAC efficiency, energy savings, and available incentives:

DOE Energy Saver - The U.S. Department of Energy's guide to saving energy at home, including detailed information on central air conditioning and efficiency standards.
ENERGY STAR - The EPA and DOE joint program for identifying energy-efficient products, including certified HVAC equipment.
AHRI Directory - The Air-Conditioning, Heating, and Refrigeration Institute's directory for looking up certified equipment ratings and performance data.
ACCA - The Air Conditioning Contractors of America, offering resources for finding qualified contractors and understanding proper installation practices.
DSIRE - The Database of State Incentives for Renewables and Efficiency, a comprehensive source for finding rebates, tax credits, and incentive programs in your area.
EIA Electricity Data - The U.S. Energy Information Administration's monthly electricity reports, including average rates by state and region.

Questions or Feedback

If you have questions about the calculator, suggestions for improvements, or notice any issues, please contact us. We appreciate feedback that helps make this tool more useful.

For in-depth guides on SEER ratings, efficiency comparisons, and HVAC topics, visit our guides section.

Popular starting points: SEER Rating Chart for a complete efficiency reference, Savings Calculator Guide to understand how upgrade savings are calculated, or our HVAC Efficiency Calculator Guide for a comprehensive overview of all our tools.

Explore Our Guides

Dive deeper into HVAC efficiency with our comprehensive guide collection:

Reference

About SEER Calculator