BTU Calculator for Home Heating

Calculate the BTUs needed to properly heat your home based on square footage and climate zone.

Calculate Required BTUs

Zone 5 - Cold (50 BTU/sq ft) Zone 4 - Cool (45 BTU/sq ft) Zone 3 - Moderate (40 BTU/sq ft) Zone 2 - Warm (35 BTU/sq ft) Zone 1 - Hot (30 BTU/sq ft)

Reference: US Climate Zone Map

How to Calculate BTUs for Home Heating

Calculating the BTUs (British Thermal Units) needed to heat your home is essential for selecting the right furnace size. This calculation takes into account your home's square footage and climate zone to determine the appropriate heating capacity.

Formula and Components

The basic formula for calculating required BTUs is:

\[BTUs = Square Footage \times BTUs\;per\;Square\;Foot\]

Where:

  • BTUs (British Thermal Units): The amount of heat required to raise one pound of water by one degree Fahrenheit
  • Square Footage: The total heated area of your home in square feet
  • BTUs per Square Foot: A climate-based factor that varies by region (typically 30-60 BTUs per square foot)

Calculation Steps

  1. Measure your home's total heated square footage
  2. Determine your climate zone's BTU factor
  3. Multiply square footage by BTU factor
  4. Consider additional factors like insulation and ceiling height

Example Calculation

Let's calculate the BTUs needed for a 2,000 square foot home in a moderate climate zone:

  1. Square Footage = 2,000 sq ft
  2. Climate Zone Factor = 40 BTUs per sq ft
  3. Calculate total BTUs:
    \[2,000\;sq\;ft \times 40\;BTUs/sq\;ft = 80,000\;BTUs\]

Therefore, this home would require an 80,000 BTU furnace for adequate heating.

Visual Representation

Square Footage BTUs

This diagram shows how BTUs distribute throughout a home's square footage. The red arrows represent heat distribution, with the size of the house directly affecting the total BTUs required for heating.

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