? actual difference between hot water heaters from supplyhouses and big box stores

The label!

On ocassion I have found a handful of different labels in the bottom of the box. Assembly must have been confused as to which brand they were supposed to be packaging that day.

The tanks with longer warranties are the same as the 5 or 7 year. They are just playing the insurance game with the extra $$.

Some brands and models still use brass drain valves, upsell models may have two anode rods, nicer nipples for connection.

Sometimes they will remove or cheapen some features to meet a specification and use a unique model number for the batches sold to large distributors/retailers.

the different labels are probably so when different marketing operations sell different "brands" whoever they hire to do the actual work can slap the label that matches the "brand" that they sold on it.

you should put them all on or leave them in the envelope with the instructions.

i looked at a home depot commercial catalog that had like key cards and soaps and things like that with all the different brandings of some motel chain.

If i'm going to spend more on the tank itself i'm going to go with stainless or plastic.

i know what the utility tells me they are and they are slightly above what the manufacturer specifies. different manufacturers have different specs, not sure if it is different alloys or different interpretations of the risk or maybe a little of both.

I've seen guys returning hotwater heaters at HomeDepot. States NonReturnable in big letters. So who ends up with that returned item?

The dumpster.

Generally, the consumer stores specify a cheaper price from the manufacturer. The manufacturer often cuts back here and there to grant that price. You'll see an exclusive "HD" model number and maybe a plastic drain valve, a single anode, perhaps a less costly control.

Most obvious of this were Delta faucets. The Home Depot line was Chinese junk: Plastic spigots, plastic handles. The supply houses carried a higher line that was US-made plated brass at three times the price. Now it seems they are all pot-metal or plastic Chinese junk.

We agree with Intplm that Bradford White is our go-to for water heaters. They're also pretty costly. The gas ones we install usually see 12-15 years, but that's with very good water quality. We only buy from local supply houses. We call and the tank is usually delivered in an hour.

that was why i didn't succeed the first time i tried to install a faucet when i was like 12 with the peerless install your own faucet. the box had been opened and was missing the instructions and some parts but i didn't know that. i think it was worse with chain stores like meijer in the 80's when that happened. there used to always be that one box that was beat up and taped back together on the shelf. now they usually either send it back and sell it as refurbished or throw it out.

note that peerless used to be the branding of the cheaper delta/masco stuff, plastic body, plastic ball

I can tell you for a fact that the Lowe's version of the Honeywell TH8110 thermostat has (or at least had, I haven't checked since I originally noticed) a different casting of the case, made with different plastic, than the supply house version. Who knows what other changes have been made.

I have found that in some cases they do dial it down. Heck, they have even created a line of cordless power tools. Remember the first Ridgid cordless power tools? I went through that orange tool set within a year. The things fell apart. They were not and or are not the Ridgid quality product that many of us have come to know.