No. This is a myth. In fact, heat is harmful to the diaper’s waterproof outer shell.
Most of our diaper pockets and all of our covers have an outer layer of thermoplastic polyurethane (TPU) fabric. TPU is a biodegradable waterproof fabric that is made via heat lamination instead of chemical bonding. TPU cannot withstand hot water or high heat.
The maximum washing temperature for our diaper pockets and covers is 95 degrees F or 35 degrees C. Higher temperatures can damage the elastic as well as the waterproofing.
We recommend that you wash your diapers in cold water. The colder the water, the softer the diapers will become.
DO NOT wash diapers in hot water or tumble dry on high heat. Doing so will void your warranty and cause tiny cracks in the laminate.