"Most people are aware that outdoor air pollution can damage
their health but may not know that indoor air pollution can also
have significant effects. EPA studies of human exposure to air
pollutants indicate that indoor air levels of many pollutants may
be 2-5 times, and occasion more than 100 times, higher than
outdoor levels. These levels of indoor air pollutants are of
particular concern because it is estimated that most people spend
as much as 90% of their time indoors." Unlike outdoor air,
indoor air is recycled again and again. This causes it to trap and
build up pollutants. Common pollutants include dust, mold and
spores, pollen, pet dander and smoke.
Sick Building Syndrome
"Over the past several decades, our exposure to indoor air
pollutants is believed to have increased due to a variety of
factors, including the construction of more tightly sealed
buildings, reduced ventialtion rates to save energy, the use of
synthetic building materials and furnishings, and the use of
chemically formulated personal care products, pesticides, and
household cleaners."
The high incidence of indoor air pollution has brought a new
phrase into the English language: Sick Building Syndrome. Symptoms
include headaches, dizziness, sinus congestion, itchy or watery
eyes scratchy throats nausea lethargy, and an inability to
concentrate. Sick building syndrome can lead to repiratory
infections and can aggravate symptoms associated with allergies
and asthma.
The effects of indoor air pollution can be costly in the work
place. Symptoms, such as those listed above, may negatively impact
the work performance of employees and may lead to increased
absenteeism. It has been estimated that contaminated air results
in medical costs of about $1 billion dollars a year and costs
employers approximately $60 billion a year in employee sick leave
and lost production.
The most energy efficienct buildings are especially susceptible
to sick building syndrome. These facilities are tight:
they do not allow indoor air to escape or outdoor air to seep in.
Most pollutants are so small (about half the size of a sharp
pencil point) that standard throw away air filers trap only 15% of
the pollutant particles in your air. As on an airplane, the same
is is circulated over and over again and so are the pollutants
that air contains. In fact, the particles you see in a beam of
afternoon sunlight streaming through window only represent about
1% of the of airborne contaminants, most of which you can't see.
Fortunately, indoor air quality can be greatly improved by the use
of proper filtration systems, which trap and remove the pollutants
that build up in the air, and by the regular maintenance of your
building's heating and cooling systems.
All cooling and heating systems utilize some type of filter in
their return air vents. However the standard cardboard
frame filters used by most consumers are only about 15%
effective in removing dust and particles from the air. They have
no effect on pollen, micro-organisms, smoke or other similar
pollutants.
Electrostatic filters are more effective than
standard filters. However, as they get dirty, they quickly become
less efficient. To maintain efficiency, they should be hosed off
on a regular basis. Because they can be cleaned and reused, they
are more economical, in the long run, than the standard throw away
filters.
Under the Atmospheric Dust Spot Efficiency test, electrostatic
filters rate at 20% efficiency. For marketing purposes, the
manufacturers and retailers of electrostatic filters use the "arrestance
test" for rating their efficiency. This is a less stringent test
than the Atmospheric Dust Spot Efficiency Test and may result in a
rating of up to 95% for the electrostatic filter.
Electronic air cleaners produce the best
results. They capture up to 95% of all airborne pollutants,
including bacteria, dust, animal hair, dust mites, mildew, lint,
fungus, smoke, cooking grease, bacteria and even many viruses.
(They rate at 80% - 90% efficiency on the stringent Atmospheric
Dust Spot Efficiency Test).
According to Trane, "An air cleaner actually
draws the dirt out of the air, so your wallpaper and paint stay
cleaner longer. And, you don't have to clean draperies, upholstery
and other furnishings as often." These same air pollutants may
also harm your air conditioning equipment and may seriously reduce
its life span and its energy efficiency. An effective filtration
system can pay for itself by increasing energy efficiency and
prolonging the life of your cooling system. It can also eliminate
the need for professional air duct cleaning. Your entire
environment benefits from an electronic air cleaner.
| How do electronic air cleaners work?
As the air in your home or place of business circulates
through your heating or cooling system, it carries millions of
airborne particles into the ductwork. The electronic air
cleaner's pre-filter captures the larger particles. The
smaller particles which pass through the pre-filter receive a
positive electronic charge. These particles are then attracted
(like magnets) to grounded metal plates. Clean, filtered air
is then circulated back into your residence of place of
business.
Electronic air filters use about as much electricity as a
30-watt light bulb. |
Filter Effectiveness Ratios
(Chart by Trane) |
If your home uses a gas fueled furnace or gas powered
appliances, they must be properly maintained to prevent the
release of carbon monoxide. Carbon monoxide is the leading cause
of accidental poisoning in the United States. It is colourless,
odourless, and tasteless and is virtually impossible for the human
senses to detect. In fact, because carbon monoxide is so hard to
detect and is so deadly, it has earned the nick-name "The Silent
Killer". Most accidental carbon monoxide poisonings occur from
house fires, malfunctioning home-heating systems and hot-water
heaters. The most common symptoms include headache, nausea,
vomiting, dizziness and fatigue.
To reduce the risk of carbon monoxide poisoning
inside your home or place of business, have your furnace serviced
annually by a licensed technician. An annual check-up should
include a thorough inspection of the heating unit for cracks,
holes, and leaks which can release carbon monixide into the air.
All Seasons
air heating and cooling performs annual heating check-ups
for homes and businesses in Riverside and San Bernadino Counties.
While proper maintenance of your gas powered furnace and
appliances is your best safeguard against carbon monoxide
poisoning inside your home or place of business, you may wish to
invest, as well, in a carbon monoxide detector. If you use a
detector, be aware that carbon monoxide weighs less than oxygen
and can be present in the upper part of a room (close to the
ceiling) long before a detector placed on the floor will detect
it. A good detector will run between $30 and $80.
How Your Air Conditioner Works
Air conditioning is the conditioning of air within a
defined space, usually a residence or a place of business.
Conditioning usually involves heating
or cooling, humidifying or dehumidifying and fitering or
cleaning air. If you have a central air conditioner, your system
cools and dehumidifies the defined space. Heating is accomplished
by an add-on to the system (such as an electric heat strip) or by
a seperate unit, such as a furnace.
Central air conditioners are split systems: an outdoor unit
(the condensing unit) and an indoor unit (air handler
). The function of an air conditioner is to transport
heat from one station to another. The vehicle your system
uses to carry the heat is called a refrigerant, commonly
referred to as Freon.
The comppressor in your outdoor unit canges the refrigerant
(or "Freon") into a high temperature, high pressure
gas. As that gas flows through the outdoor coil, it loses
heat and condenses into a high temperature, high pressure
liquid. This liquid refrigerant travels through copper tubing
into the evaporator coil. There the refrigerant expands.
Its sudden expansion turns the refrigerant into a low temperature,
low pressure gas. This gas then absorbs heat from the air
circulating in the duct work. The cooled air is then distributed
back through your house or place of business. Meanwhile,
the heat absorbed by the refrigerant is carried back outside
through copper tubing and released into the outside air.
Dirty coils and improper refrigerant levels can cause your
system to cool less efficiently than it should. An inefficient
system means higher energy bills. It also forces your compressor
to work harder than is necessary and can actually shorten
the life span of your unit. An annual air conditioning inspection
by a licensed technician includes an inspection of the coils
and the checking of your refrigerant charge, to insure that
your system is running efficiently.
As the warm air circulating through your ducts passes over
the evaporator coil, it is quickly cooled and can no longer
hold as much moisture as it did at a higher temperature.
The excess moisture condenses on the outside of the coils
and is carried away through a drain. The process is similar
to what happens when moisture condenses on the outside of
a glass of ice water on a hot, humid day.
Occassionally, the drain lines may become clogged and your
system will not drain properly. This can result in a drain
pan overflow, leading to water leaks in your ceiling or
walls. An annual air conditioning inspection by a licensed
technician includes an inspection of your draining system.
During the inspection, the technician will treat your draining
system with an algaecide to retard the growth of algae,
which can clog your system.
Your cooling system consists of an outdoor unit and an
indoor unit . These two components are designed to work
together as a coordinated team to provide top performance,
maximum efficiency, and comfort. Whenever you install a
new outdoor unit, you should install a new, equally efficient
"matched" indoor unit at the same time. While
replacing the outdoor unit only may initially offer you
the lowest price, it may prove more expensive over time.
When your air conditioning components don't match, your
system may still work, but it won't perform at the promised
energy efficiency. In fact, your system could be up to 15%
less efficient than stated. You may be sacrificing comfort,
as well, as a mismatched system may have difficulty keeping
up on the hottest days. Finally, if your cooling system's
components aren't matched, it could create undue stress
on your cooling system, resulting in unnecessary, premature
failure.
The Importance of an Annual Cooling Inspection
Would you drive a car year after year without ever changing the
oil or taking it to a mechanic for a tune-up? Probably not. Like
your car, your cooling and heating systems must be maintained in
order to run efficiently and dependably. An annual cooling
check-up allows a technician to identify minor problems before
they become major ones.
ACU Airperforms annual cooling system inspections on both residential
and commercial structures.
Glossary
- Air Handler
- Also known as the "indoor unit", the air handler
is the evaporator section of your air conditioning system.
It circulates and delivers the cooled air. The indoor
unit contains the evaporator coil, an indoor fan motor
and, sometimes, a heat strip (for supplemental heating).
- Automatic Setback Thermostat
- An automatic setback thermostat or
programmable thermostat allows you to store six or more
separate temperature settings for different times of the day.
You can set the thermostat with a daily or weekly program. And
you can override the settings at any time without affecting the
daily or weekly program.
- BTU
- BTU stands for British Thermal Unit: the amount of heat
required to raise the temperature of one poud of water one
degree fahrenheit.
- Compressor
- The compressor is the "engine" which drives the condensing
unit. The condensing unit serves as a pump which compresses the
gas in the high pressure (condensing) side of the cooling cycle
and causes the refrigerant (Freon) to circulate.
- Condensing Unit
- Also known as the "outdoor unit", the condensing unit pumps
vaporized refrigerant from the air handler (indoor unit),
compresses it, liquefies it, and returns it. It contains the
compressor coil, an outdoor fan motor, refrigerant control
valves, and other necessary controls.
- Evaporator
- Found inside the air handler (indoor unit), the evaporator
is where refrigerant vaporizes and absorbs heat.
- Refrigerant
- Refrigerant is a substance which absorbs heat by changing
states (evaporating) from liquid to gas. It releases heat by
changing states (condensing) from gas back to liquid. Most
people refer to the refrigerant used in cooling systems (R-22)
as Freon. But this is actually DuPont's brand name for R-22. The
scientific name for R-22 (or Freon) is halogenated
chloroflourocarbon (CFC). Because of its destructive effect on
the ozone, the use of R-22 is strictly regualted by the
Environmental Protection Agency
(EPA). To legally buy and use Freon, an air conditioning
technician must own a recovery unit and must be
certified EPA certified. Unfortunately, many EPA certified
technicians do not always use their recovery units when
releasing Freon from a unit. Removing Freon without a recovery
unit destroys ozone and is a violation of federal law. You
should check carefully with any technician you use about how he
handles the refrigerants in your system, since misuse can result
in costly fines. ACU Air has an EPA universal
certificate and consistantly follow all EPA guidelines for the
removal and recycling of refrigerant.
- SEER
- Seasonal Energy Efficiency
Ratio is the efficiency rating for air
conditioning units. The higher the SEER rating, the better the
energy efficiency. SEER is the ratio of the amount of
BTU's used for cooling in normal annual use
to the total amount of electrial power (measured in watts) over
the same period. (Annual Cooling in BTU's/Total Watt Hours =
SEER).
- Split System
- A split air conditioning system allows the
air handler to be installed in a different location from the
condenser. While split systems generally cost more to install
than package units, they can save you money in the long run
because they are more energy efficient. Another advantage is the
reduction of condenser noise. Split systems are also often used
where there is a space problem. Ask your ACU Air technician if a
split system is right for you.
- Thermostat
- A temperature-sensitive switch that controls your heating
and cooling systems. When the indoor temperature drops below or
rises above the selected temperature setting, the switch moves
to the "on" position, and your heater or air conditioner runs to
warm or cool.
- Zoning Systems
- A zoning system allows the home or business owner to control
the environment in an individualized and energy efficient way.
The residence or place of business can be divided into 2 or more
zones. Through the use of fully modulating dampers, the system
can selectively cool or heat certain portions of the building at
given periods of the day. With some systems, indoor humidity can
likewise be displayed and controlled. A popular alternative to
zoning is having two or more units in a larger building. Each
unit controls the temperature and humidity in a given portion of
the building. Consult with an air conditioning design
contractor, such as ACU Air, to determine which of these systems
would best meet your needs.
Buying a New Air Conditioner
When your cooling system breaks down, you're often faced with
the choice of repairing your existing unit by having one or more
of the components replaced or by purchasing a new air conditioner.
Many air conditioning companies push clients to purchase new units
because there is a higher profit margin in replacing existing
equipment than there is in repairing it.
ACU Air (accurate, comfortable,
user friendly heating and air conditioning)
focuses on educating its customers so that they themselves can
make an informed decision regarding the replacement or
the repair of an existing air conditioner. Often there's no
absolute right or wrong answer. Repairs on an existing unit may be
the least expensive immediate option, but may cost the customer
more in the long run. Paying for repairs on an older, inefficient
system simply prolongs the inevitable. An older system that breaks
down once is likely to break down again. And it will consume more
energy than a newer system. In fact, installing a new, energy
efficient system can pay for itself over time.
However, there are times when simple repairs can sufficiently
prolong the life of an air conditioner so that immediate
replacement of the unit is not the most sensible option. If an air
conditioning technician has advised you to replace your unit and
you're not certain that purchasing a new unit is necessary, give
us a call. If you are located in North Harris or Montgomery
County, we'll come out and give you a second opinion at no charge.
If your unit can be repaired, we'll explain the advantages and
disadvantages of repairing versus replacing your existing unit.
And, should you choose to replace the unit, we'll provide you with
a unit replacement estimate so that you can do some comparison
shopping.
Should You Replace Both Units?
Whenever your outdoor unit (condensing unit) goes out,
an air conditioning technician likely will recommend that
you replace your indoor unit (air handler) as well. This
is because your two units must be matched in order for
your new outdoor unit to run at its promised level of
efficiency. Furthermore, mismatched units may comprimise
your level of comfort and may possibly shorten the lifespan
of your new unit. However, there are times when a customer
simply cannot afford to replace both units at once. When
replacing an outdoor unit,We customers on the costs/advantages
of replacing a functioning indoor unit versus the savings/disadvantages
of leaving the existing indoor unit in place. This allows
our customers to make an informed decision regarding
unit replacement, based on the condition of their current
cooling system, their air conditioning needs, and their
current financial situation. Unlike many contractors,
we do not "force" our clients to replace both
systems at once.
Selecting a Unit
It's a purchase you make perhaps once in ten years. You're
concerned about efficiency and comfort. But how do you know which
brand and model to choose. Understanding the standard ratings
applied to air conditioners can help.
Efficiency Ratings
In general, the more efficient the unit, the more it will cost
initially. However, the more efficient, more expensive unit will
actually save you money over time as it requires less fuel to cool
your home. Cooling efficiency for air conditioners is indicated by
a SEER
(Seasonal Energy Effiency Rating). The SEER rating tells you
how efficiently a unit uses electricity: the higher the number,
the greater the efficiency. The typical SEER rating of units
manufactured prior to 1992 is about 6.0. In 1992, the government
established a minimum cooling efficiency standard for units
installed in new homes at 10.0 SEER. High efficiency units have a
rating of at least 12.0 SEER. The maximum efficiency presently
available is 17.0 SEER.
Depending on the location of your
outdoor
(condensing) unit and the floorplan of your home, a noisy unit
may destroy the peace and quiet of your garden and may even be a
sound nuisance when you're indoors. The sound level of outdoor
units is measured in bels (similar to decibels), on a scale from 0
(barely perceptible) to 13 (the loudest). Most air conditioners
operate at 8 to 9 bels. The quietest units operate at 6.8 bels.
This may not sound like a wide range, until you learn that a 9-bel
unit is 10 times louder than an 8-bel unit. In other
words, one 9-bel unit makes as much noise as 10 8-bel units put
together.
Comfort Features
Some air conditioners come additional features that provide
greater comfort. Two-speed units can run on
low-speed (using about 50% of the energy) 80% of the time.
Consequently, they use fewer on/off cycles and produce fewer
drafts and much small temperature swings.
In order to achieve comfortable cooling and dehumidification,
the system must be correctly sized. The size of central air
conditioning is measured in tons. (1 ton =
12,000
BTU/HR).
The following is a rule of thumb guideline for sizing
residential systems in Harris and Montgomery Counties.
|
House Size |
Size of Central Air System |
| 800 -
1,000 sq. ft. |
2 Ton |
| 1,000 -
1,200 sq.ft. |
2 1/2 Ton |
| 1,200 -
1,500 sq.ft. |
3 Ton |
| 1,500 -
1,800 sq.ft. |
3 1/2 Ton |
| 1,800 to
2,000 sq.ft. |
4 Ton |
| 2,000 -
2,500 sq.ft. |
5 Ton |
Keep in mind that this is only a guideline and that skylights,
type of insulation, the number and size of south facing windows,
protective shade trees, etc. can significantly effect the size of
system required. Your contractor will make the proper
recommendation during the site inspection.
Selecting a Contractor
Improperly installed equipment may work inefficiently, wastes
your time as you set up and wait for repair calls, and, at worst,
may cause leaks in your ceiling or walls or create a fire hazard.
Make sure that the company you use is fully licensed and insured
and that it warranties its work. Below is a checklist of questions
you should ask every air conditioning contractor which bids on
your replacement system.
- 1. Are you licensed? What is your license number?
- Under Texas state law, a contractor performing any type of
air conditioning (service or installation) must possess a state
license.
ACU Air 's license number is #TACLB014226E.
- 2. Are you fully insured?
- If an uninsured contractor or any of his employees gets hurt
on your property, you could be liable for his medical bills.
Likewise you would faced with the expensive of repairing any
damage to your property resulting from an improperly done
installation.
ACU Air is fully insured by State Farm. A
copy of our insurance certificate is available upon request.
- 3. Are you EPA certified? Will you use a recovery
unit to capture the Freon when removing the old unit?
- To legally handle Freon, an air conditioning contractor must
be EPA certified and must use a recovery unit. Unfortunately,
many EPA certified technicians do not consistantly use recovery
units when releasing Freon from a unit. The recapturing of Freon
is a time consuming process, but must be done any time an old
unit is disassembled. Releasing Freon without a recovery unit
destroys ozone and is a violation of federal law.
ACU Air is EPA certified and follows all EPA
regulations.
- 4. Do you pull all required permits?
- If you live inside the city limits (of Houston or another
municipality), a permit may be required for the installation of
a new air conditioner. Permits were created to protect you, the
consumer. They insure that the job will be done safely and
correctly (in compliance with city building codes) and that it
will be inspected by the appropriate agency. If you live in a
city where a permit is required and the contractor does not
secure one, you may be required to have the job done over, even
if it was done properly.
ACU Air always pulls and posts any required permits.
- 5. Do you want to check the ductwork?
- When replacing an air conditioning unit, a contractor should
first examine the existing ductwork to insure that its size will
accomodate new equipment and to check for leaks.
- 6. What kind of warranties cover this equipment?
- Have in writing both the manufacturer's and the contractor's
warranties on the equipment and installation. The manufacturer's
warranty should specify the length of time your unit is covered
and which of the specific components are included.
- 7. What are your prices and terms?
- The contractor should provide you with a written contract
before performing the work. Make sure the quoted price includes
the equipment, installation, all permits, and taxes.
- 8. Do You Sub-Contract Installations?
- Many air conditioning companies have on-staff technicians to
examine and repair existing cooling systems, but use
sub-contractors for new installations. Know exactly who you are
working with.
ACU Air never sub-contracts installations.
How Your Heater Works
Gas fired and forced air electric furnaces distribute warm,
even heat throughout your home or place of business by heating air
and circulating it through ducts.
Furnaces create heat by burning fuel (gas, oil, or propane). When
the fuel burns, it generates hot gasses which travel through
curved metal tubing called a heat exchanger. As
air passes over the heat exchanger, it absorbs heat from the hot
metal surface. The heated air is then circulated through ducts to
warm your home or place of business. Meanwhile, the gasses
(combustion air) that are created by the burning fuel are released
outside through a metal or plastic vent pipe.
A furnace which is cracked or contains holes or small leaks can
release carbon monoxide into your home or place of business.
Carbon monoxide is colourless, odourless, and tasteless and is
virtually impossible for the human senses to detect. In fact,
because carbon monoxide is so hard to detect and is so deadly it
has earned the nick-name "The Silent Killer". Most accidental
carbon monoxide poisonings occur from house fires, malfunctioning
home-heating systems and hot-water heaters. The symptoms of carbon
monoxide poisoning vary significantly. The most common acute
symptoms include headache, nausea, vomiting, dizziness and
fatigue. Many carbon monoxide victims frequently attribute these
non-specific symptoms to viruses or flu-like illnesses. Severe,
continued cases of carbon monoxide poisoning may lead to coma and
death.
To reduce the risk of carbon monoxide poisoning
inside your home or place of business, it is extremely important
that your furnace be serviced annually by a licensed technician.
An annual check-up should include a thorough inspection of the
heating unit for cracks, holes, and leaks which can release carbon
monixide into the air. To reduce the risk of fire, the flame
itself should checked for a proper mixture of air and gas.
Likewise the safety and limit switches should be tested to insure
that the fan runs whenever the heat exchanger is hot and that the
unit will shut off should the flame burn beyond the confines of
the box. ACU
Air performs annual heating check-ups in north Harris and
Montgomery Counties. Click
here
for additional details on what our check-ups include.
Electric furnaces use an air handler (fan) to
force air across a heat exchanger (or
resistor). The resistor is a wire coil which uses
electricity to create heat. The heated air is then circulated
through ducts to warm your home or place of business.
While electric furnaces are generally cleaner and safer to run
than gas powered furnaces, they too can benefit from an annual
heating check-up. A thorough inspection of your heating system can
insure that it is running as efficiently as possible and is
providing maximum comfort for you and your family. The inspection
can also detect minor problems which can be treated before they
cause serious damage to your heating system.
ACU Air
performs annual heating check-ups in north Harris and Montgomery
Counties. Click
here
for details on what our check-ups include.
Heat Pumps
A heat pump works by moving naturally occurring heat in or out
of your home. Even in the cold of winter, free outdoor heat is
available to warm your home. In summer, the heat pump reverses the
process and pumps warm indoor air into the outdoors, cooling your
home like a normal air conditioner. Because a heat pump does not
burn fuel, it is safer and cleaner to run than a gas powered
furnace. (For diagrams and a more detailed description on how heat
pumps work, visit our
Heat Pumps
web page).
If your home or business uses a heat pump, make sure that your
heating and air conditioning technician is certified to work on
heat pumps before he services your unit. Heat pumps operate on
different principals than traditional furnaces and air
conditioners and so are engineered differently. Not all state
licensed heating and air conditioning technicians are qualified to
service heat pumps. To receive heat pump certification, a
technician must receive formal training in heat pump design and
repair and must pass a test administered by the
Refrigeration Service Engineers
Society (RSES). ACU Air has been heat pump
certified by the RSES.
Buying a New Heater
The three most important factors to evaluate when you're
considering the purchase of a new furnace are
quality, efficiency, and
comfort features.
Gas versus Electric
Gas Furnace
Where natural gas is available, a
gas furnace
is nearly always cheaper to run than an electric one. Bear in
mind, however, that gas furnaces utilize a flame to burn fuel and
generate toxin fumes. In a well-maintained unit, the fumes are
contained inside the heat exchanger and exit your home or place of
business through a vent.
If you own or purchase a gas furnace, it is extremely important
to have the unit examined once a year by a licensed technician.
The technician will inspect the unit for cracks, holes, and leaks
which can release carbon monoxide into your home or place of
business. ACU Air performs an
annual
heating check-up for residences and businesses in North Harris
and Montgomery County.
Electric Furnace
Electric furnaces are generally more expensive to run than gas
furnaces. However, because they do not employ a flame and do not
produce carbon monixide, they are a cleaner and safer source of
heat than are gas furnaces.
Heat Pumps
A third option for heating your home or place of business is
the purchase of a
heat pump.
When you buy a new car, its quality determines how well it will
perform and for how long. The same is true of a new furnace.
Selecting a brand name that has a reputation for quality and
reliability can save you headaches and extra expenses down the
road. Consult your contractor for the brand(s) which would best
suit your needs.
If you have a residence or place of business in north Harris or
Montgomery County and need to replace your existing heating
system, a ACU
Air technician will be glad to examine your home or business
facility, advise you on which of the available brands of furnaces
(based on their respective features, efficiency, reliability, and
warranties) would best meet your needs, and provide you with a
free estimate for purchase and installation of a new furnace.
Gas
furnaces are classified by AFUE (Annual Fuel
Utilization Efficiency) ratings which identify how efficiently
they use fuel. Generally, the higher the AFUE rating, the less
fuel a furnace will require to heat your home or place of
business. Units with higher efficiency ratings are usually more
expensive to purchase than those with lower ratings. However,
units with higher AFUE ratings cost less to run and can actually
save you money in the long run.
In 1992, the government established a minimum AFUE rating of
78% for furnaces installed in new homes. In contrast, many
furnaces manufactured prior to 1992 had efficiency ratings as low
as 60%.
Mid-Efficiency Furnaces
Mid-efficiency furnaces (also called non-condensing
furnaces or induced draft furnaces)
offer efficiencies from 78% to 80%.
High-Efficiency Furnaces
High-efficiency furnaces (also called condensing
furnaces or sealed combustion furnaces)
offer AFUE ratings from 80% to 96%.
Some furnaces offer additional features that provide greater
comfort as well as improved efficiency.
Two-Speed Furnaces
Two-speed furnaces can run on low speed up to 90% of the time,
so they operate more quietly and run for longer periods of time
than single-speed furnaces. Longer operating periods translate
into fewer on/off cycles, fewer drafts (from the blower kicking on
less often) and much smaller temperature swings (only one or two
degrees instead of the four-degree swings common with single-speed
furnaces). They also provide better air circulation which helps to
prevent air stratification (warm air rising to the ceiling and
cold air settling on the floor). In short, with a two-speed
furance, you get consistent, even heat throughout your home.
Variable-Capacity Furnaces
Variable-capacity furnaces provide the ultimate combination of
comfort and efficiency. In addition to the benefits of two-speed
furnaces, they offer "smart" motors that can monitor your home's
comfort needs and automatically adjust the volume and speed of air
to provide the most efficient heating or cooling.
Variable-capacity furnaces can also save you money on
electricity. Even gas burning furnaces use electricity to power
their fans. The "smart" fan motors on
Carrier's variable-capacity
furnaces use less electricity than a 100-watt light bulb.
The fan which comes with your variable-capacity furnace can
also save you money during the summer. If you use the fan
operation continuously through the summer months, it will increase
the efficiency of your central air conditioning system .
Sound Levels
Furnaces don't have a standard sound rating system such as the
bel rating
system used for air conditioners and heat pumps.
However, two-speed and variable-speed furnaces typically
operate at a lower sound level then do standard models. As stated
above, these furnaces run for longer periods and at lower speeds
than traditional furnaces. Consequently, they produce less noise
as the blower motor kicks on less often.
Certain variable-capacity models also provide a "ramp on"
feature which gradually introduces warm air into your ducts. This
helps to prevent the "creaking" noises produced by ducts expanding
and contracting.
