How are the sizing capacities of heating
and cooling systems measured?
heating and cooling systems are sized
according to their tonnage. One (1) ton equals
12,000 BTU/H. Residential systems can range from 1
to 5 tons.
What size HVAC system should I have?
to popular belief there, is no rule of thumb for
sizing a system to a home. Depending upon the
construction of your home, one (1) ton of air
conditioning can cool anywhere from 300 to 800
square feet of home. The only way to insure the size
of the system you purchase will be large enough to
cool your home, but not any larger than you need, is
to have your home's individual heating and
cooling needs evaluated by a licensed
How is the efficiency of heating and
cooling equipment measured?
S.E.E.R. (seasonal energy efficiency
ratio) is the amount of cooling your system will
deliver per dollar spent on electricity. For
example, a 3-ton unit may have a S.E.E.R. efficiency
rating of 13, 14, or 15. The higher the S.E.E.R. the
more efficient the system will be. The S.E.E.R.
rating of any given unit can range anywhere from 13
How can I increase the efficiency and
life of my home's heating and cooling systems?
important thing you can do is clean and replace your
filters frequently. Also, a system heats and cools
more evenly when the blower is in the "on" position.
The blower provides constant air movement throughout
the home, and allows for better filtration. Finally,
shades, drapes, shutters, or screens should be
installed on windows that are exposed to extreme
Is a system with more capacity better?
larger system with more capacity delivers less
comfort and costs more to operate. An air
conditioner is at its least efficient when first
turning on. A system with too much capacity will run
in numerous short cycles, turning on and off
repeatedly, therefore causing it to be less
efficient. Also keep in mind that an air conditioner
only removes humidity when it's running, so a system
with shorter run cycles doesn't remove humidity from
the air very well.
How long should my system run in a cycle?
no exact answer for how long your system should run
during each cycle. The average air conditioner is
sized to remove the heat from your home as fast as
it comes in, on a 110° day. Therefore, ideally, on a
110° day the system should be able to keep up with
the incoming heat, but not gain on it and be able to
turn off. The cooler it is below 110°, the more the
system will cycle on and off.
Should I try to keep my system from
running too much?
time your system starts up, it will use a lot of
electricity and not produce much cooling. Usually a
system that is too small to cool the home is more
economical to run but delivers less comfort. Even
though it runs nonstop, it will usually consume less
power than a larger system that cycles on and off.
As a rule of thumb, a unit that is either on or off
is less expensive than one cycling on and off.
What air temperature should my air
temperature your system produces depends on the
temperature of the air going into the system.
Generally, the air produced should be 18°-20° below
what enters the system. So if the air entering the
system is 80°, the air exiting should be about
60°-62°. However, that only works on a system that
has been running at least 15 minutes on a warm, dry
day with a home that is about 80° inside. On a mild
day, with an indoor temperature in the low 70's, or
during humid conditions, the air coming out may only
be 15°-17° cooler than what enters.
What temperature should I set my
Obviously the time of year becomes a big factor for
desired temperature settings. In the summer months
the average temperature setting is 78°-80°, in the
winter 70°-72° seems to be the most common setting.
Remember, when leaving your house; try to avoid
drastic temperature changes. Do not set your
temperature back more than 5°; this will cause your
unit to work harder to achieve the desired
What are the advantages of a programmable
Different programmable thermostats offer many
different features. However, because they are
electronic, they are all more accurate and efficient
than thermostats that contain mercury. With
programmable thermostats you can control the
temperature in your home at different times of day
without ever touching your thermostat. Because
everything is automatic, you will never forget to
change the setting on your own.
How often should I replace my filters?
optimum efficiency and filtration, we recommend that
you replace your disposable filters at least once a
month. If you have washable filters, they should be
cleaned once a month.
What maintenance should I do on my air
important maintenance you can do is to change your
filters regularly. Ground mounted outdoor units need
to be kept clear of debris, clutter; weeds or
landscaping that can grow too close and reduce the
airflow to the unit. Also, keep pets away from the
unit because pet urine can cause expensive damage.
Use caution with a weed trimmer around the unit to
prevent damaging control wiring. Any additional
maintenance should only be performed by qualified
often should I have maintenance done on my air
should have maintenance done on your air
conditioning system twice a year. This not only
ensures maximum efficiency, it enables us to foresee
any possible problems that may occur in the near
Is there anything I should check prior to
calling for service?
Check to be sure that the air handler or furnace is
plugged in. Check that the breakers and the
disconnects are turned on and be sure the thermostat
is set correctly.
How much does a new replacement system
the many different makes, models and customer needs,
price is an issue that can only be solved by doing a
thorough evaluation of your home and existing
equipment. There is no charge for an in-house
Are there any air conditioning systems
that are safe for the environment?
Several manufactures have developed new systems that
contain the environmentally friendly R410A, or Puron,
Do electronic air cleaners really work?
they can actually play a big part in your complete
home comfort. We have a variety of whole-house
filtration devices. Some electronic air cleaners can
even remove dust particles and pollen as small as
.10 micron. Visit our products page for more
information about the electronic air cleaners we
Should I close the registers and doors to
areas of the home that I do not use on a regular basis?
Closing the registers will decrease the systems'
airflow and efficiency. Every system is designed to
cool a certain number of square feet. By closing
registers and doors in certain rooms, you disrupt
the airflow and cause your air conditioning system
to work harder to distribute air to other areas of
your home. Your system will work harder, to cool
less space, making it cycle more and become less
Why are humidifiers used more in heating
cool outdoor air enters a home it tends to dry out
as it warms up, which increases the static
electricity in the home and causes sinus problems.
Adding a humidifier with help to add moisture back
into the air and limit sinus problems. In the
summer, even with outdoor relative humidity hovering
around the single digits, the humidity in your home
tends to be around 40%. The average comfort range
for relative humidity in a home is from 35 to 45%.
During the heating season, my heat pump
delivers warm air, but not hot air, and will operate for
long periods of time. Is that normal?
this is normal. A heat pump generally produces air
that is 80°, which is considered warm, and will heat
the house evenly. However, 80° may feel cool to your
hand, which is usually closer to 90°.
the heating season, my heat pump makes a "whooshing"
sound and I feel cool air coming from the supply
registers. Is that normal?
During the cold weather months, frost will
accumulate on the outdoor coil. This will cause the
heat pump to go into a defrost cycle anywhere from
1-10 minutes, depending on the amount of ice on the
coil. The system will return to the heating mode
once the ice is gone.
How do I know if my A/C unit is big
purchasing a replacement system you should always
make sure your system is sized properly. Our
representative will provide a heat load calculation
to determine the proper size and make the
appropriate recommendation. Remember, bigger is not
much does it cost to
run my unit a year?
HVAC Operating Cost
Analysis to help determine that figure. It varies
on several factors.
That is why when you get an estimate on your home
the potential dealer should do an in-home evaluation
to determine the proper size unit for your home.
Air Design Heating And Cooling 696
San Ramon Valley Blvd. # 177, Danville, CA 94526
PH: (925) 837-4328 – (800) 920-2665 – (925) 837-4700 (Fax)– CA
Serving quality HVAC, air conditioning and heating services to
Danville, San Ramon, Dublin, Pleasanton, Livermore, Castro Valley,
Walnut Creek, Lafayette, Orinda,
Moraga, Concord, Martinez