Evening star., 1938-07-23
A|R-COND|T|0N|NG
COSTS EXPLORED
Office Building Equipment
= Found Dependent on
Many Factors.


Although the demand for air con-
ditioning in Office and business build
ings is becoming greater all the time,
it cannot be bought for 10-year-old
structure in package form, points out
Fred B. Orr of Chicago in the current
publication Of the Institute of Real
Estate Management of the National
Association of Real Estate Boards
The type of air-conditioning system
to be selected for Office buildings or
portions of commercial buildings, such
as restaurants and stores" he says,
depends upon many factors-geo-
graphical location of building, number
of floors in height, square feet of area
per floor, exposure to sun and wind,
type OF occupancy (totally occupied by
one company or broken up into small
suites for many different tenants),
relative cost of power and water for
condensing purposes, location of
spaces to be air conditioned with re-
lation to fan rooms and machinery
rooms. Each building should be
given careful study for all methods Of
cooling, unit or central, If the type
offering the most advantages is to be
selected"
Mr.. Orr lists the common types of
cooling and dehumidifying systems,
then from experience in the engineer
ing problems of Chicago Loop build
ings, cites specific building conditions
which would make advantageous the
use of one or the other of these types.
Takes Note of Definition.
Quoting the definition of air con-
ditioning of the American Society of
Heating and Ventilating Engineers,
1.-THE simultaneous control of the tenn
perature. moisture content, motion and
physical and chemical constituents of
the air to produce conditions most
conducive to human comfort and
health" he comments: The most
important word in this definition is
control"
Listing items entering into operat-
ing charges, Mr. Orr takes for example
q 5,000-square-foot restaurant with q
$4,000 system complete, of 30-ton
capacity. OF the total charges (Which
might be s2,477 annually on such a
system) he calls attention to the fact
that the largest item Gn the assumed
case OF $1,000 is due to investment
charges, including interest, deprecia-
ton and taxes.
Where 1t is possible to balance
against the cost of air cleaning and
humidity control against the savings
they effect over period of years in
cleaning costs, furniture repair bills
and the Like, the extended life of fur
nishings and equipment within the
building would in itself more than
return the investment in air condi-
tioning over the life Of the furnish
angs, the writer holds
Benefits Many Furnishings.
"Draperies, rugs, decorations, fur
niture and furnishings would not
only have a much longer life under
properly humidif1ed and cleaned cir
but would also keep that new appear
ance and require much less attention
cleaning and laundering" he points
out. Furniture would not come
apart and pianos would not need tun.
ing 50 frequently" Paintings anc
tapestries would maintain their In.
tended luster and finish. Books would
not dry out and break apart.
Ihe low maintenance cost in clean
Ing and decorating, as q rule. COM
pletely offsets the operating cost, and
thus, greater comfort and endowment
are obtained at no appreciable cost
whatever"
Comparatively large construction
changes that may be involved in al,
conditioning existing buildings he lists
as including complete Turing of ducts
or ceilings, cutting and patching OF
finished partitions or paneled Offices
etc.
1t is practically impossible to list ap.
proximate prices for this portion OF
the work of installation
For year-round conditioning, in
cluding all charges except steam fol
heating, the annual cost to own and
operate a system will be from 20 to 4C
cents per square foot of area, depend
ing upon the hours use of cooling pc,
tcdI, ILLS dulllOTlty says.
Breaks Down Cost.
e'For purposes of estimating operat-
ing costs, each ton of refrigeration re.
quires one horsepower hour of motor
and two gallons of condensing water
per minute. Depending upon the eli
mate and other factors and applica-
ton, yearly costs are based upon the
use of the above quantities for from
600 to 1900 hours per year for the
cooling season. The ventilating fan.
If operated all year require additiona
electric power.
THE initial cost of the central sta.
ton type of air conditioning system
in existing buildings usually runs from
$125 up to S205 per square foot ol
rentable area to be conditioned . .
These figures are based upon the as.
sumption that a direct radiation
heating system of some type is already
in use for heating the building during
the winter months with the air condi.
tioning system equipped with indirec
heaters to temper air for ventilation
purposes and to be used In conjunction
with the existing direct radiation sys'
TEN. Where large areas are to be con-
ditioned, the cost per square foot fol
installation is usually in the love-
bracket. For smaller systems of 5000
square feet of floor area or under
the prices usually range in the inter
mediate or higher bracket
These prices do not include an,
large construction changes.
Relatively few people as yet hav,
the necessary experience to engineer
air conditioning. and many failures
have been registered" the articl'
warns.
The duration Of the glacial periot
4s astinaafod Ia hn a laast s0a AnI