Standard Efficiency Furnace & AC System Selector
Easy System Selector Tool
Use this tool to guide you to the best heating and cooling solution for your home.
Furnace BTU (Select One)
Please select a furnace BTU to continue.
AC Tonnage (Select One)
Please select an AC tonnage to continue.
Please select an airflow orientation to continue.
How to Determine the Right BTU or Tonnage for Your HVAC System
Use the guide and tools below to find the right system size for your space.
STEP 1: LOCATE YOUR CURRENT SYSTEM'S INFO
You can usually find the BTU listed on your furnace's data sticker, often located inside the cabinet door or on the inner or outer wall of the cabinet. On an air conditioner, the data sticker is typically found on the outer panel of the outdoor condenser unit, often near the electrical disconnect box.
Look for terms like M/N, Prod, Mod No, or Model Number to identify your system. These numbers can also help you find a replacement if needed and the product manual (if you need to look up the BTU/Tonnage).
STEP 2: CALCULATING BTU AND TONNAGE
You can also use the model number to determine BTUs. You'll find an even number within the model number string. Multiply this number by 10,000 to calculate the unit's BTU.
From there, tonnage is typically calculated by dividing BTUs by 12,000 (since 1 ton = 12,000 BTUs).
If you don't have product data available, you can also use our sizing calculator to use square feet to determine your needs.
Furnace Data Sticker
Model Number: DGAT070BDF
BTU: 70,000
AC (Heat Pump) Data Sticker
Model Number: ACIQ-24-HP
BTU: 24,000 TONNAGE: 2.0
| MODEL # | BTU | TON |
|---|---|---|
| 18 | 18,000 | 1.5 |
| 24 | 24,000 | 2.0 |
| 30 | 30,000 | 2.5 |
| 36 | 36,000 | 3.0 |
| 42 | 42,000 | 3.5 |
| 48 | 48,000 | 4.0 |
| 60 | 60,000 | 5.0 |
Furnace orientation matters because it determines how air moves through the system, ensuring proper performance, efficiency, and compatibility with your home's ductwork.
Using the wrong orientation can cause poor airflow, inefficiency, or equipment damage.
Tonnage in heat pumps refers to the unit's heating or cooling capacity, where 1 ton equals the ability to remove 12,000 BTUs of heat per hour.
BTUs in furnaces measure the heating capacity, indicating how much heat the unit can produce per hour.
