PEX Radiant Floor Heating Calculator

Heat Output Formula:

\[ Q = A \times BTU/ft^2 \times F_f \]

Heat Output (Q): BTU/h

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1. What is a PEX Radiant Floor Heating Calculator?

Definition: This calculator estimates the heat output (in BTU/h) for PEX radiant floor heating systems based on floor area, BTU per square foot, and adjustment factors.

Purpose: It helps HVAC professionals and homeowners determine the heating capacity needed for radiant floor systems.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ Q = A \times BTU/ft^2 \times F_f \]

Where:

\( Q \) — Heat output (BTU/h)
\( A \) — Floor area (ft²)
\( BTU/ft^2 \) — Heat output per square foot (BTU/h·ft²)
\( F_f \) — Adjustment factor (typically 1.0 for standard systems)

Explanation: The floor area is multiplied by the desired heat output per square foot, then adjusted by system-specific factors.

3. Importance of Heat Output Calculation

Details: Proper heat output estimation ensures comfortable indoor temperatures, energy efficiency, and correct system sizing.

4. Using the Calculator

Tips: Enter the floor area in square feet, BTU per square foot (default 25 BTU/h·ft²), and adjustment factor (default 1.0). All values must be > 0.

5. Frequently Asked Questions (FAQ)

Q1: What's a typical BTU/ft² value?
A: Most residential systems use 20-30 BTU/h·ft², depending on climate and insulation.

Q2: When would I change the factor (F_f)?
A: Adjust for high ceilings (1.1-1.3), poor insulation (1.2-1.5), or commercial spaces (1.5-2.0).

Q3: How do I measure floor area?
A: Multiply length by width of each room, then sum all areas to be heated.

Q4: Does this include heat loss?
A: No, this calculates output needs. Heat loss calculations should be done separately.

Q5: How does this relate to boiler sizing?
A: Total BTU/h output helps determine appropriate boiler capacity (typically 1.25x calculated load).