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Your new heating
and cooling
system should be
a custom fit for
your home.
Sizing and a
handful of other
installation
practices can
dramatically
affect how well
your new
equipment will
deliver comfort
and savings.
Expect to pay a
little more for
a good
contractor who
follows these
practices.
Calculate the
size of
equipment
Seal and
insulate ducts
in attics and
crawlspaces
Check and
correct air flow
Proper
refrigerant
charging
Equipment
placement
Calculate the
size of
equipment
For starters
your new
furnace, boiler,
heat pump or air
conditioner
should be sized
to fit your
home. You can
request a copy
of the design
load calculation
used to
determine the
right size of
equipment for
your home. A
good contractor
will not size
your equipment
solely on the
square footage
of your house or
assume that your
existing
equipment was
sized properly
in the first
place. Proper
equipment sizing
is based your
home's heat loss
during cold
weather and heat
gains during
warm weather.
To complete
the design load
calculation the
contractor will
need to take
measurements
during the
initial visit to
your home and
ask you some
questions. The
calculation is
usually done
using software,
and should be
based on
professional
guidelines such
as Manual J from
the Air
Conditioning
Contractors of
America (ACCA)
or similar
method.
Oversized
equipment can
cause reduced
comfort and
excessive "air"
noise.
Oversizing will
shorten the life
of the equipment
by causing it to
cycle on and off
more frequently
than a
properly-sized
unit. Undersized
equipment, with
airflow that is
too low, can
reduce the
efficiency of
the air
distribution and
accelerate wear
on system
components,
leading to
earlier failure.
After the
design load
calculation is
completed,
ducts, supply
registers, and
return grilles
can be sized and
selected using
professional
guidelines in
ACCA's Manual D
or similar
method.
Seal
and insulate
ducts in attics
and crawlspaces
If you're
installing a
central air
conditioner,
furnace or heat
pump ask your
contractor about
the condition of
your air ducts.
A good
contractor
should be able
to test your air
ducts to
identify and
seal leaks.
- Duct
sealing
should be
done by a
professional
using
mastic,
metal-backed
tape or
aerosol-based
sealing.
- In some
instances,
your
contractor
may advise
you that it
is necessary
to replace
or add
ducts. If
there are
insufficient
supply
registers or
return air
grilles in
your home,
it may be
necessary to
install
additional
ducts to
accommodate
the need for
registers or
grilles.
When
possible
ducts should
be located
within
conditioned
space. If
the ducts
must be in
unconditioned
space (attic
or
crawlspace)
they should
be
insulated.
Check
and correct
airflow
For central air
conditioners,
furnaces or heat
pumps there is
an optimal air
flow for comfort
and savings.
- If
airflow is
too high,
duct leakage
increases
and the
temperature
at the
register is
not
sufficient
for optimal
home
comfort.
- If
airflow is
too low,
distribution
efficiency
drops and
accelerates
the wear on
system
components
leading to
premature
failure.
A good
contractor will
test the air
flow of your
heating and
cooling system
and make
adjustments for
optimal
performance.
Typically,
testing and
adjustments
should be done
after duct
leakage repairs
have been
completed.
Proper
refrigerant
charging
If your are
installing a new
central air
conditioner or
heat pump you
should know that
recent field
studies suggest
that
approximately
75% of installed
cooling
equipment may
have incorrect
amount of
refrigerant.
Incorrect
refrigerant
level can lower
efficiency by 5
to 20% and can
ultimately cause
premature
component
failure,
resulting in
costly repairs
that could have
been prevented.
A good
contractor will
use one of three
methods,
recommended by
equipment
manufacturers,
to verify the
correct
refrigerant
level. These
methods include
super-heat,
sub-cooling, or
weigh. Ask your
contractor how
they verify the
refrigerant
level is
correct.
In addition,
you should know
that since 1992,
in order to
protect the
earth's
atmosphere
(ozone layer),
all technicians
must be
certified to
handle
refrigerant. Ask
them to show you
proof of
refrigerant
handling
certification.
Equipment
placement
Placement of new
equipment is
unique for every
home, but a good
contractor
should follow
manufacturer's
installation
instructions for
best results.
For example,
Indoor equipment
should be
installed in
conditioned
space, or a
space that is
well insulated.
The Outdoor
compressors
should be placed
out of the sun
and kept free of
debris.
Equipment should
be installed in
an accessible
area for easy
maintenance.
Allow plenty of
room for free
airflow on all
sides of the
equipment.
Thermostats
should be placed
away from direct
sunlight,
drafts,
doorways,
skylights and
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