sorry but you have no idea what you are talking about. The fucking water heater tank is designed to AVOID heat transfer/loss.

The BS about plumbing supply houses having "better quality" fixtures is just so much bullshit too. There is no way manufacturers can afford to run separate lines/sign separate contracts with Chinese manufacturers to "support their plumbers" etc

That said, you are right that efficiency is king. Unfortunately efficiency is gained through complexity which is the enemy of reliability.

"Brands" make nearly zero difference to reliability [they are all made by the same lowest cost factory in China/Vietnam etc]. What does make a difference? Competent install