All of these layers are black in colour and are excellent at absorbing ambient heat from their surroundings. (educationbusinessuk.net)
For instance, try setting the starter atop your water heater, refrigerator, or another appliance that might generate ambient heat. (kingarthurflour.com)
In simple terms, this means that thaw from below (ambient heat held by the earth) can be very slow to reach the base of your carpet. (educationbusinessuk.net)