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BTU Calculator

Estimate a simplified heating load from area, temperature difference, and heat-loss factor.

BTU Calculator Inputs

Results computed instantly — your data never leaves your device.

BTU Calculator Results

Real-Time

Estimated heat load

8750.00 BTU/hr

100% Client-SidePrivate & Secure

How to Use the BTU Calculator

  1. 1

    Enter conditioned floor area.

  2. 2

    Enter the indoor/outdoor temperature difference.

  3. 3

    Enter a project heat-loss factor.

  4. 4

    Review the simplified hourly BTU estimate and obtain a professional sizing calculation for installation.

Formula & Mathematical Basis

Estimated heat load = area × temperature difference × heat-loss factor.

Variable Key

A

Area in square feet

ΔT

Temperature difference in °F

F

User-entered heat-loss factor in BTU/hr/ft²/°F

📝 This screening model omits windows, infiltration, solar gain, duct losses, occupancy, and local design temperatures.

Step-by-Step Examples

1

Screening estimate

Scenario: 1000 ft², 30°F difference, factor 0.5.

  1. 1.Multiply 1000 by 30.
  2. 2.Multiply by 0.5 BTU/hr/ft²/°F.
  3. 3.Review the hourly estimate.
  4. 4.Compare with a Manual J or equivalent professional assessment.
✅ The simplified estimate is 15,000 BTU/hr.

Practical Use Cases

  • Early comparison of heating-load assumptions.
  • Explain how area and temperature difference affect a screening estimate.

Common Pitfalls

  • Using this to buy equipment without a load study.
  • Confusing BTU/hr with total seasonal energy.
  • Using a heat-loss factor outside its intended context.

Frequently Asked Questions

Is this an HVAC sizing calculation?

No; it is a simplified educational estimate.

Does it include cooling load?

No; this route models a heating-style screening load.

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