First built in?
As a Brit I feel on shaky territory, but surely amongst the very first built ins in a mainstream domestic situation would be dishwashers - chiefly, I suppose, in the form of the "electric sink" but its strikes me that the earliest dishwashers (pre WW2) were built in in some form or another.
dj-gabriele makes an interesting point about what actually defines a built in unit - is it a unit that could only be built in or is a freestanding unit that has been built in? For example the vast majority of dishwashers sold here would look like portables to US/Canadian readers, even though they are designed to be built in, even with doors on the front so that from, the outside they cannot be distinguished from the rest of the kitchen.
I was going to say that here in the UK, the first built-ins would have been ovens and hobs until 1970s but then I realised that was incorrect in that the English Rose company (which has been discussed here before) produced fully built in fridge and (chest) freezer long with a range (what US would describe as apartment size) back in the 1950s. I can also think of a couple of situations where a Hoover single tub washer (like a Hoovermatic wash tub) was installed as part of a sink unit along with a wringer. And there was the "Sink a matic" from the 1960s which was basically a stainless steel sink with an impellor in the side to wash both clothes and dishes with a mechanical power take off to drive a mixer.
But apart from those exceptions it was oven and cook tops until the 1970s, although things designed for free standing use could still be built in, even to cabinet runs. The first departure would have been fridges and freezers, designed to co ordinate with built in ovens and followed by dishwashers, washers and driers designed to take a panel in the front to match the cabinets. Later then they came with doors to make then "disappear" - do you even have those in the US?
In my consideration of this question my mind turned to my favourite 1940s American kitchen - that of Rita Phipps in letter to three wives, where both styles are illustrated, the dishwasher behind Thelma Ritter in the first picture, and the fridge beside Ann Southern and Kirk Douglas in the second
Al
