ASHRAE Journal - September 2019 - 36

ASHRAE - CELEBRATING 125 YEARS

Cease Firing by Hand!-Automatic
Heating
By 1900, many homes and buildings, particularly in cities, were
equipped with central steam, hot
water or hot air heating systems.
Before the 1920s, most homeowners
using central systems heated with
hand-ﬁred coal furnaces or boilers.
They had to descend into a basement
and contend with coal shoveling
from a "coal bin," ash clearance and
a method of temperature control
requiring a judgment of how much
coal to use and how much draft to
allow for the ﬁrebox. Although thermostat-controlled draft regulators
had been available since the 1880s,
they were seldom used in homes or
small businesses. Automatic ﬁring of
heating equipment was hampered
at ﬁrst by lack of widespread availability of electric power and reliable electric motors, as previously
discussed. Once the motors were
available, inventors had to ﬁgure
out how to apply them to the ﬁring
of heating systems. They also had to
develop controls that would permit
direct control of the equipment.
These efforts began before 1900 and
accelerated through the next two
decades. During WWI, a coal shortage and government initiatives to
conserve energy gave a push to automatic system development in the
United States.
Homeowners and businesses
were used to "banking" coal ﬁres at
night, waking up early to stoke the
ﬁre with fresh coal, opening and
adjusting draft dampers, and then
waiting for bulky heating systems
to respond. Guesswork, weather
conditions and experience dictated
how much coal and draft to use,
but this was inherently wasteful.
36

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The ﬁrst electric-motor-powered
"coal stoker," which mechanically
fed coal and removed ash from a
boiler or furnace and could be controlled by thermostat, was placed
on the market in 1912, and by the
1920s, automatic coal systems were
available from many manufacturers. However, this improvement in
coal-ﬁred systems soon succumbed
to what was seen as better fuels-oil
and gas.
Wartime restrictions on and
subsequent shortages of coal
stimulated the use of oil and gas as
substitute energy sources for heating. Certainly oil and gas had been
investigated and even used in limited circumstances for heating prior.
Before World War I, there were several manufacturers of domestic oil
burners. Underwriters Laboratories
certiﬁed an oil burner in 1912. The
ﬁrst oil burner with high-voltage
electric ignition, tradenamed the
"ELECTROL," was introduced in
1918. By the mid-1920s, the market
for household and commercial oil
burners skyrocketed.
Gas heating advanced too. By
1900, there was a well-developed
infrastructure for gas distribution
in many cities for gas lighting, but
there was no real incentive to push
the use of gas for heating until the
gas utility companies saw their
revenue decline as electric lighting advanced. Casting about for a
way to increase gas use, they began
to investigate its use for heating.
For example, the Ohio Gas Light
Company installed gas heating systems in 50 homes as an experiment
in 1891. After 1900, some furnace
and boiler manufacturers added
gas-ﬁred equipment to their lines,
but gas equipment did not really

S E P T E M B E R 2 0 19

FIGURE 3 The first night setback thermostat was
introduced in 1907. (Engineering Review, December
1908, p. 104).

take off until the World War I coal
shortages. By that time, electrically
operated gas valves had been developed, so the heating system could
be readily controlled by thermostat.
Although thermostatic control for
heating had been invented in the
1830s in England, it was not until
the 1880s that it was improved and
extensively promoted by innovators
such as Albert Butz, Warren Johnson,
William Powers, William Sweatt and
others. Various heating thermostat
designs were available by 1900.
The clock-operated night setback

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ASHRAE Journal - September 2019

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