The amount of BTU (British Thermal Units) that is left unused when cooking on a gas stove can vary depending on several factors, such as the efficiency of the stove, the size and type of cookware, and the cooking techniques used. Additionally, individual cooking practices can also influence the amount of wasted heat.
It's challenging to provide an exact or average value for the amount of BTUs left unused, as it can differ from one cooking session to another. However, some studies and estimates suggest that traditional gas stoves might have an efficiency rate of around 40% to 55%. This means that about 45% to 60% of the BTUs generated by the gas are not effectively utilized for cooking and are wasted.
The wasted heat can result from factors such as improper pot size (using a pot that is too small for the burner), using cookware with uneven bottoms, not using lids on pots and pans, and having flames that extend beyond the sides of the cookware. Inefficient cooking techniques or leaving burners on at excessively high settings when lower settings would suffice can also contribute to BTU waste.
To improve energy efficiency and reduce wasted BTUs while cooking on a gas stove, consider using appropriately sized cookware, matching pot size to burner size, using lids to trap heat, and adjusting the flame to the necessary level for the cooking task. These practices can help optimize the use of BTUs and conserve energy during cooking.