🔹 Value Explanations

1. 3600
   → The number of seconds in one hour.
   This converts your stopwatch measurement (in seconds) into an hourly rate.

2. Revolutions
   → How many full turns of the gas meter dial you timed.
   Example: If the ½ ft³ dial spins 3 times while you’re timing, then revolutions = 3.

3. Seconds
   → The total stopwatch time for those revolutions.
   Example: If 3 turns took 90 seconds, then seconds = 90.

4. Dial Size (ft³ per revolution)
   → How many cubic feet of gas each turn of the dial represents.
   Common values:

   • ¼ ft³ = 0.25

   • ½ ft³ = 0.50

   • 1 ft³ = 1.0

   • 2 ft³ = 2.0

5. Heat Content (BTU/ft³)
   → The energy content of the gas, often shown on the gas bill. There are three ways to enter it:

   • Therm Factor × 1000 (e.g., 1.066 × 1000 = 1066 BTU/ft³)

   • Direct BTU/ft³ value (e.g., 1025 BTU/ft³)

   • MJ/m³ × 26.84 (conversion from metric units)

6. BTU/hr
   → The calculated input rate of the appliance in BTUs per hour.

🔹 Optional Values

7. Rated Input (BTU/hr)
   → The manufacturer’s nameplate value for how much gas the appliance is supposed to use.
   Example: Furnace rated input = 100,000 BTU/hr.

8. Tolerance (%)
   → Allowed deviation when comparing measured vs. rated input.
   Typical: ±5–10% (tight spec is ±5%).

9. Comparison Result
   → After calculation, the script compares the measured BTU/hr with the rated input:

   • ✅ Within tolerance

   • ⚠️ Overfiring (burning too much gas)

   • ⚠️ Underfiring (not burning enough gas)