North Carolina History Digital Textbook Project

A technological tour of the Biltmore Estate

By Sue Clark McKendree

LEARN NC was a program of the University of North Carolina at Chapel Hill School of Education from 1997 – 2013. It provided lesson plans, professional development, and innovative web resources to support teachers, build community, and improve K-12 education in North Carolina. Learn NC is no longer supported by the School of Education – this is a historical archive of their website.

Interpreting central heating systems

Central heating was first developed by the Romans and was reintroduced in England by the 1790s. By 1890 nearly all English country homes had central heating of some kind. However, cast iron stoves continued to be in such demand in the U.S. that they were still featured at the 1915 Panama-American Exposition. Unlike the vast majority of turn-of-the-century rural residences that relied on fireplaces and coal stoves, Biltmore House was centrally heated. Situated on a ridge overlooking a river valley, the house was exposed to cold winter mountain winds. To warm such a massive structure proved to be a particular challenge to architect Richard Morris Hunt and his contractors.

To design a workable system, Hunt contracted the services of New York City engineer John D. Clarke. Hunt and Clarke had worked together on many other buildings, but the vastness of Biltmore House demanded both innovation and machinery of unprecedented size and performance. Guests would never see the heating apparatus, but they would certainly enjoy the comfort of warm rooms in which to read, eat, and sleep.

Interpreting the boilers and heating system

These three boilers were manufactured by the Kewanee Boiler Corporation of Kewanee, Illinois.

The Kewanee Boiler Corporation advertised itself to be a “Division of American Radiator & Standard Sanitary Corporation” and manufactured “Steel Heating Boilers, Water Heaters, Tanks, Garbage Burners, [and] Power Boilers… Main Office and Factory, Kewanee, Illinois.” In addition to building the three massive steam boilers for Biltmore House, they also supplied the Tabasco water heater.1

The boilers originally burned wood and soft lump coal. The coal was shoveled out of the coal bins into coal carts, and out of the carts into the firebox. It would have taken a crew of firemen working around the clock to keep the boilers fired. The Boiler Room was dark, hot, dirty, and noisy, but vital to the functioning of the House during cold weather.

In 1896, [Mr.] Davis and [Mr.] Abernathy, two of the engineers who formerly worked on the construction railroad, were “now running the furnaces at the house.”2 Henry Clark is mentioned as having been a “colored fireman” in turn-of-the-century correspondence.3 A 1903 – 1904 “Budget for the Electrical Department” included an expense of $547.00 for the salary of the Night Fireman.4 Frank Cody, who retired several years ago, was employed as a fireman as late as the 1970s.

  • The system for heating the water was known as the “Horizontal Tubular Return System.”
  • The boilers consisted of two parts: a firebox and a tank of water which had to be heated to boiling point to produce steam; the capacity of the three boilers was approximately 20,000 gallons of water.
  • Air heated by the firebox not only circulated around the tank of water but also through it. A chimney in the backs of the boilers allowed the hot air to circulate through and around the tank. The air in the horizontal tubes running from one end of the tank to the other (hence the name of the system) heated the water more efficiently.
  • The ashes and cinders were shoveled out of the bottoms of the boilers into the ash and cinder cart that was metal–lined so that it would not catch fire. The cart was then wheeled to the right and around the corner to a hand-operated elevator to be cranked up to the ground level. The ashes and cinders were used to maintain roads on the Estate.
  • The boilers were insured by the “Hartford Steam Boiler Inspection & Insurance Co., of Hartford, Conn.,” who inspected the boilers on December 1st and 3rd, 1898.5
  • The large metal ball on top of Boiler #1 is attached to an arm with a hook. It appears to be some kind of weight that would have activated a valve that was part of the system.
  • The water level in the boiler could be monitored by means of a “sight glass” (now broken) at the upper left of boiler #1. To maintain the proper level, water was added to the boiler by manually opening and closing the valves. When boilers #2 and #3 were modified, equipment was added which maintained the water level automatically, although the level could still be visually monitored using the sight glass.
  • The steam pressure was maintained at about 5–7 pounds psi (per square inch). This was considered to be a low-pressure system.
  • Boiler #1 appears as it did at the turn of the century.
  • Boiler #2 was converted from burning lump coal to hotter-burning stoker coal in the 1920s. The coal was shoveled into a feeder that regulated its flow into the boiler. It was much safer as well as being much more efficient, since the coal was no longer being shoveled directly into the open fire. It also required much less labor. The mechanism for regulating the rate at which the coal was fed into the firebox is mounted opposite on the wall.
  • Boiler #3 was converted to oil in the 1970s.

Interpreting the heat distribution system

Steam was piped from the boilers to the radiators in the Basement and to radiators mounted inside the numerous air shafts throughout the House. The Basement level of the House is heated by direct radiation with the radiators clearly visible in the rooms. Cast iron radiators were still very new, and only became available in the 1890s.6 Most of the upper floor areas were heated by indirect radiation.

  • Radiators were mounted inside airshafts that ran inside the walls from the Basement and Sub-Basement levels to the registers that can be seen in the walls on the upper floors of Biltmore House. They were mounted horizontally so that the cool air had to pass through them in order to be heated.
  • Fresh air was vented into the airshafts below the radiators from the chases or tunnels that run beneath the Sub-Basement.
  • This delivery system needed no fans or blowers. The lighter hot air rose through the shafts from the radiators and continuously pulled fresh outside air into the system. This is called natural convection. Mention that you will talk about the heat circulation system in more detail later in the tour.
  • The black wooden box on the wall to the let of the pipes and sink was the speaking tube to the Butler’s Pantry and Main Kitchen. Perhaps this was how the firemen were called to meals. Or, perhaps, this is how the cook requested more coal for the stove. It also might have been used by to communicate with the Dynamo Room staff when power needs changed.

Interpreting the fireplaces and the supplemental heating system

The supplemental heating system at Biltmore House consisted of 65 fireplaces. The fireplace was thought to be the visual focal point in a room, even after the availability of central heat. All of the public rooms, as well as all of the guest and family rooms, and even some for the servants’ rooms, feature fireplaces.

Herman Muthesius wrote in The English House at the turn of the century that “To the Englishman the idea of a room without a fireplace is quite simply unthinkable. All ideas of domestic comfort, or family happiness, of inward-looking personal life, of spiritual well-being center round the fireplace…to remove the fireplace from the home would be like removing the soul from the body… It is the rallying-point in which the whole essence of the room is concentrated [and] the soul of the decoration of the room… What luxury to sit before an open fire!”7

“By 1890 nearly all English country homes had central heating of some kind, with the radiators—concertinaed pipe looking like giant intestines - discreetly hidden behind carved or wickerwork panels, usually under bench seats in the window embrasures. The question was no longer whether they were provided but how effectively they worked. At best, they took the chill off a room, the screens diminishing still further the modest amount of heat given off by the radiators. In no pre-First World War home was the architect rash enough to rely on central heating alone. All rooms had open fires, which had to be stoked, cleaned and emptied of ash.”8

  • The larger fireplaces on the First Floor burned firewood, while the smaller, shallower ones on the upper floors may have burned coal [see information below on coal suppliers].

Firewood was supplied from the Estate. The Landscaping Department reported on March of 1895 that it had “hauled and shipped over 150 cords of wood — cut from road lines and Deer Park — to Biltmore, for sale, and use at the brick works.”9 Frank Owens (whose brother Sylvester worked for Chauncey Beadle as chauffeur, houseman, and garden assistant) was a firewood cutter on the Estate.10

  • The 65 fireplace flues fed into 16 chimneys located on the roof of Biltmore House. Architect Richard Morris Hunt included elaborate carvings on each of the chimneys on the south end of Biltmore House, each with a different design motif. One suggestion for why the chimneys on the south end of the House were more ornate is that they could be seen and appreciated by garden strollers and thus merited special architectural attention. Today, thirteen of the fireplaces have been converted to gas. They burn on winter evenings when the house is open for special events, such as Christmas at Biltmore.


Give the group the opportunity to ask questions. Ask them to turn to look at the coal bins behind them. Point out the drill mounted on the wall. Demonstrate how it was hand-operated, and allow guests to turn the wheel if they choose.