How can you avoid wasting heat when using the cook-top of the ranges?

To avoid wasting heat when using a cooktop, ensure that the pot or pan matches the size of the burner to minimize heat loss. Use flat-bottomed cookware for better contact with the heating surface, which enhances efficiency. Additionally, keep lids on pots while cooking to retain heat, and turn off the burner a few minutes before the food is done to take advantage of residual heat.