European Origins of a Pennsylvania German House
The Flurküchenhaus (Corridor-Kitchen House)

Image: Adapted from: Gerald L. Foster, American Houses - A Field Guide to the Architecture of the Home

 Above: A corridor-like kitchen and a three-room floorplan define a typical Pennsylvania German Flurküchenhaus. The floorplan sometimes includes a fourth room, as in Lancaster County’s 1719 Herr House. The Stube (living room / dining room) is heated by a stove. The Anglo / British houses were usually heated with fireplaces, rather than with stoves.

 Evolution of a Flurküchenhaus in Europe
into a Pennsylvania Geman House:

 Above: Lancaster’s 1719 Herr House is a four-room example of a Flurküchenhaus / corridor-kitchen house. German-language image adapted from Siegfried Heim, "Wohnen in Wolfurt", Heimat Wolfurt, Heft 21, 1998, Link, Link.

 Evolution of a House Fire Pit into a Germanic Stove:

 Above: Siedlungsentwicklung und Baugeschichte in Oberstdorf und Umgebung (Settlement, Development, and Building History), 1988, by Mathias Kappeler and Franz Vogler, Complete text online.

 The Pennsylvania Flurküchenhaus (Corridor-Kitchen House),
Their Prototypes in European Housebarns:

Image above: Revised after Genlex.de. and Altes Bauernhaus.

European prototypes of the Pennsylania Flurküchenhaus (corridor-kitchen house) can be found in Europe as farmhouses attached to barns (housebarns). Housebarns in Germany and Switzerland have various names, including Einhaus (single-house), Eindachhof (one-roof-house) or Wohnstallhaus (residential barn house).
American historian have often been unable to locate European prototypes for the Pennsylvania Flurküchenhaus. But early examples of these corridor-kitchen houses survive in the Rhineland. These houses in Europe are often camouflaged by being attached to a barn. And these early European houses are often hidden by later additions. But our vernacular Germanic houses trace their roots back to those farmhouses.

European Comparison to the Herr House:
A German Housebarn with Attached Flurküchenhaus.
It’s a farmhouse at Siedelsbrunn, Hesse, Germany:

Above: Das Bauernhaus des Odenwaldes und des südwestlichen Deutschlands, Henkelmann, 1908, (color added).

 Above: The Siedelsbrunn Farmhouse
Below: The Herr Farmhouse

 The Siedelsbrunn Farmhouse and its Attached Barn:

Images above: Das Bauernhaus des Odenwaldes und des südwestlichen Deutschlands, Henkelmann, 1908, Complete text online.

Emigrants from Siedelsbrunn to North America in the 1700s...
Brought their architectural traditions with them:

Above: The village of Siedelsbrunne in Hesse, Germany.
Image: Wikipedia

The German-language Wikipedia article for the village of Siedelsbrunne explains why this community saw much emigration to Pennsylvania in the early 1700s. 
Translation to English: "At the end of the Thirty Year's War (1648) the place [Siedelsbrunn] was almost deserted. After the devastating war, electoral Palatinate pursued a
resettlement policy on its territory characterized by religious tolerance. But the wars that erupted in the troubled following period, such as the War of the Palatine Succession (1688–1697) and the War of the Spanish Succession(1701–1714), destroyed many of the efforts and tens of thousands of Palatines emigrated to North America and Prussia, among others.
"
These emigrants brought their cultural heritage with them, including their architecture.

 More Historic Housebarns in Germany
With Flurküchenhaus Floorplans
Illustrated in a 1906 Book about Farmhouses:

Farmhouse at Herbholzheim in Baden-Württemberg:

Above: Farmhouse at Herbholzheim in Baden-Württemberg Image: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer, 1906. (English translation and color added)

Farmhouse at Binau in Baden-​Württemberg:

Above: Farmhouse at Binau in Baden-Württemberg Image: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer, 1906. (Color added)

Farmhouse at Neukenroth in Oberfranken, Bayern:

 Above: Farmhouse at Neukenroth at Oberfranken, Bayern. Image: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer, 1906. (Color added)

Farmhouse at Brombach in Hesse:

 Above: Farmhouse at Brombach in Hesse. Image: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer,, 1906. (Color added)

 Another European Comparison to the Herr House:
A German Flurküchenhaus
It’s a farmhouse at Blankenloch, Germany:

Image above left: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer,, 1906.

Image above left: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer,, 1906. (Color added)

Image above left: Das Bauernhaus im deutschen Reiche…, Prof. Dr. Dietrich Schäfer,, 1906. (Color added)

Similar Flurküchenhaüser in Switzerland
Illustrated in the 1908 Meyers Lexikon:

  Above: The floorplan of a Swiss farmhouse from the 1908 Meyers Lexicon (color and translation added.) The floorplan reveals a three-room, corridor-kitchen farmhouse which is an iconic form of early Pennsyvlania German houses.
The floorplan shows an Eckbank (corner bench) and dining table in the Stube / living room. Corner benches and tables were typical of the Rhineland. These benches also were typical of Germanic houses here in Pennsylvania, such as the 1719 Herr House. The floorplan shows that the living room and bedroom were both heated by a stove. The complete text for this Meyers Lexikon is online.