Bard 2100-073 - Manual (Page 6)

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GENERAL DESCRIPTION
WHAT DOES THIS GUIDE SHOW?
This operational cost savings guide has been prepared to show theoretical
cost savings for Bard dual fuel “add-on” heat pumps when used with either
existing or new furnaces. It covers add-on applications for electric, oil,
propane gas and natural gas type forced air furnaces. It Includes both air
source heat pumps and ground water source heat pumps at many combinations of
gas, oil and electrical rates. It enables the user not only to make a
theoretical operating cost comparison at today's fuel costs but also at
future estimated higher energy costs.
It Is Important to understand that this Is a theoretical comparison between
fuels. Actual operation costs can vary depending on many difficult to
predict variables such as the actual design heating or cooling load, air
Infiltration, and wind effects, solar effect, efficiency of existing furnace,
severity of weather for a given heating or cooling season and also individual
usage pattern.
SPECIAL FEATURE—FUEL SAVER MODULE
These estimates utilize the Bard Fuel Saver Module which permit the heat pump
to operate below the balance point to maximize the energy savings. For each
application an analysis should be made to determine the economic balance
point which Is the outdoor temperature at which It becomes more cost
effective to shut the heat pump down with an outdoor thermostat. This
temperature varies with each combination of fuel cost and furnace and heat
pump efficiency level. Refer to tables included in the instructions with the
Fuel Saver Module.
FURNACE EFFICIENCY
For purposes of these cost estimates, furnace efficiency levels of 100% AFUE
for electric, 78% AFUE for natural and propane gas and 78% AFUE for oil was
chosen. We recognize that any variation in efficiency from these values will
change the operating cost somewhat. These values were chosen to best
represent typical efficiency levels of most equipment in the field today.
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