Do cold candles burn out faster than room temperature candles?
It is counter-intuitive, but you did the experiment and clearly it’s true – cold candles burn faster. You can’t argue with the data! The question is – why? The cold candle burns the wax faster. This could be because it has a bigger flame, a hotter flame, better air flow to the flame, or something else. Burn the 2 candles side by side and see if you can spot a difference. Measuring the size of the flame should be easy. You could measure the temperature with a thermometer with the bulb held a few cm away, or use a thermocouple in the flame itself. To look at the airflow, use some smoke from a lighted taper. My guess is that in the cold wax the flame digs a deeper, narrower pool of molten wax, which flows faster into the wick for some reason. Without more information it’s just speculation though.