I’ve heard that over and over for years so I looked into it when I was looking at faucets and toilets for redoing my kitchen and bathroom.

I was told for years the “Home Depot version” is inferior, and that’s (mostly) wrong. Home Depot does have cheap(er) Koehler products but they have different part/product numbers. If the part/product numbers are the same, it’s the same product. So if you call a supply house and get a number then go online and find the same number, it’s the exact same product.

So when the plumber tried to tell me the $580 K-22973-VS faucet I found at Home Depot was lesser quality than the $820 K-22973-VS he was going to get from the supply house, I asked him for the product number and he balked. I told him I talked to Koehler and all the sudden he lowered his prices to Home Depot/Lowe’s prices. That’s when I told him to fuck off and I’d supply all the hardware and just pay him hourly.

I don’t know about rinnai specifically, but now I assume any reference to “the supply house” is a way to pad the bill for extra profit.