Passionate, innovative thinkers work here, grow here and impact the next generation. We are driven to provide the perfect degree of comfort for homes and businesses.
Whether you’re buying a new furnace or water heater for your home or business or you simply want to know more about the equipment you already own, this is your one-stop source for everything you need to know about Rheem® comfort solutions.
When purchasing a new system, it's very important that a licensed
dealer visit your home to perform a complete evaluation, or “load
calculation.” By doing this, he or she will look at all the factors
that affect the heat gain and loss of your home. The dealer will take
into account the climate you live in, as well as the size, shape, and
orientation of your home; it's not enough to merely calculate square
footage, although your Rheem Pro will do that, too. What type of
insulation and how much you have is important, along with window size,
type, quantity, and the directions they face. Your Rheem Pro might
measure walls and floors, see what materials the house is made of,
check seals, estimate air leakage, and locate existing vents and
ductwork. By combining these and other factors, the dealer will
evaluate what size unit your home requires. However, if you are
replacing an existing system, you can give your dealer a starting
point. You can provide to your Rheem Pro the model and serial numbers
of your existing units, found on the rating plate. But you will still
require a load calculation. An over or under sized unit is one of the
most common problems with any system; when a licensed dealer performs
a load calculation, you will have a more efficient system and a more
comfortable home.
Should you have a problem with your system, Rheem has developed the
following guidelines to assure that your problem receives proper
attention.
To better assist your independent HVAC contractor, please furnish the
model and serial numbers on each piece of your equipment and the date
of installation. First, determine the type of equipment from the two
categories shown below. The photos and diagrams will help you locate
the model and serial numbers of your equipment, if they are not found
on your original warranty or sales invoice.
Glossary of Terms
AFUE
Annual Fuel Utilization Efficiency. Used to express the efficiency of gas furnaces. The higher the AFUE rating, the more efficient the unit. Federal law has required that all new residential furnaces built after January 1992 operate with an AFUE of 78% or higher. All Rheem® furnaces are manufactured to exceed these requirements with a minimum AFUE of 80%. If your furnace was built before 1992, chances are it is operating with an average efficiency of around 60%. Most of the heat is lost up the chimney or out the exhaust vent – devices used by older furnaces to expel dangerous fumes created by the furnace, such as carbon monoxide, carbon dioxide, aldehydes, and even soot. Modern furnaces use more technologically advanced venting techniques to achieve greater energy efficiency. An important note: Be sure to ask your installing contractor if your chimney or exhaust vent is suitable for use with your new equipment.
AHRI
The Air-Conditioning, Heating, and Refrigeration Institute (AHRI) is the trade association representing manufacturers of air conditioning, heating and commercial refrigeration equipment. AHRI’s 300+ member companies account for more than 90 percent of the residential and commercial air conditioning, space heating, water heating, and commercial refrigeration equipment manufactured and sold in North America. Rheem is an active member of AHRI.
BTU
Short for British Thermal Unit. The amount of heat required to raise or lower the temperature of one pound of water by one degree Fahrenheit.
BTU/HR
The heat transfer rate of HVAC equipment is measured in British Thermal Units per Hour.
CAPACITY
Usually measured in BTUs or tons, capacity refers to an air conditioning or heating unit’s ability to cool or heat a space. For instance, a 20-ton air conditioning unit has twice the capacity of a 10-ton unit.
CFM
A unit to express movement of volume, including air, in Cubic Feet per Minute. A 400 CFM air handler moves 400 cubic feet in one minute.
COMPRESSOR
The compressor plays an integral role in cooling your home. It is the device responsible for pumping refrigerant through the refrigerant lines and the coil, making the transfer of heat from inside your house to the outdoors possible. Rheem uses high-quality compressors throughout its residential air conditioning and heat pump line for quiet, efficient, and trouble-free operation for many years to come.
CONDENSER
The coil responsible for dissipating heat to the surrounding, outside air. Also called the condenser coil, or outdoor coil, its role is reversed when a heat pump is used in heating mode.
CONTOUR COMFORT CONTROL™
The brain behind the most advanced furnace technology available today. Used in the Rheem Classic 90 Plus Modulating Gas Furnaces with Contour Comfort Control™, this breakthrough technology can keep temperatures throughout your house constant—as constant as one-half of one degree of your thermostat setting. Conventional furnaces turn on and off when temperatures fall or climb to a pre-determined level, delivering warm air (usually much warmer that the air in the house), until the desired temperature is achieved, then turning off. The Rheem Classic 90 Plus Modulating Gas Furnace is different. The fan speed and heat output are automatically and constantly varied. The result is that air flows from the registers at the precise temperature you select, for lower utility bills and greater comfort. You can also use up to six optional remote sensors (mounted in closets or other strategic locations) to help the Contour Comfort Control™ system analyze temperatures throughout your home. The system then uses this information to direct furnace activity accordingly, effectively eliminating hotspots.
COP
The Coefficient of Performance rates a heat pump’s ability to efficiently use electricity in its operation. The Air Conditioning and Refrigeration Institute provides the Coefficient of Performance at 47 degrees Fahrenheit and 17 degrees Fahrenheit.This is because a heat pump is more efficient at higher, outside-air temperatures.
dB
The relative loudness of a sound is expressed in dB, short for decibel. As an example, the sound of a human voice talking is around 70 dB. (See also SRN.)
DOE
A federal agency, the Department of Energy, sets the standards for efficiency throughout the HVAC industry and monitors consumption of energy sources.
DOWNFLOW
A term used to describe the direction of airflow through a furnace. A downflow furnace takes return air from the top, heats it, and then delivers the warm air from the bottom.
DUCT/DUCTWORK/DUCTING
A central heating and air conditioning system uses many components to heat or cool air. This warm or cool air is then transferred to different registers throughout the house via special, flexible, large-diameter pipes or ducts. The system of ducts throughout your house is often referred to as ductwork or ducting.
EER
Energy Efficiency Ratio. The ratio of the cooling capacity of the air conditioner in BTUs per hour to the total electrical input in watts. This measure is determined by comparing test units to the Air Conditioning and Refrigeration Institute specifications.
EFFICIENCY
A general term used to describe how effectively a heat pump, air conditioning system, or furnace converts incoming energy to outgoing energy. The higher the number, the more efficient the unit, and the lower the operating costs.
EVAPORATOR COIL/EVAPORATOR
An integral part of the indoor unit of a heat pump or air conditioning system. So called because when warm air passes over a coil filled with liquid refrigerant, the refrigerant itself evaporates and absorbs some of the heat. This gas refrigerant is then pumped to the outdoor coil, where it releases heat into the surrounding air and returns to its liquid state.
HEAT EXCHANGER
Responsible for transferring heat from furnace burners to the blower. Rheem uses some of the finest heat exchangers in the industry with limited lifetime warranties on some models.
HORIZONTAL FLOW
A term used to describe the direction of airflow through a furnace. A horizontal flow furnace takes return air from one side, heats it, and then delivers the warm air from the other side.
HSPF
Heating Seasonal Performance Factor. It measures the efficiency of the heating portion of your heat pump. The Department of Energy minimum is 6.8. (Similar to SEER.)
HUMIDIFIER
Usually available as an optional accessory, a humidifier is used to inject water vapor into the dry, heated air expelled from a furnace/air handler. The benefits can be improved efficiency and a more comfortable living environment.
HVAC
Heating, Ventilating and Air Conditioning. Used to refer to the industry at large, particularly dealers of heating and air conditioning equipment.
INDOOR COILS
Split-system home comfort systems use two main components to deliver air for a comfortable living environment. The indoor coil is the device responsible for transferring heat from indoors to the outdoors (or the reverse in the case of a heat pump in heating mode). Most modern systems are designed to achieve maximum efficiency when the indoor unit (coils and blower) is properly matched with the outdoor unit (air conditioner or heat pump). For best results, be sure to replace both the indoor and outdoor units at the same time.
KILOWATT
A unit used to express 1,000 Watts. Denoted as “kW.” Note that the “W” in “kW” is always capitalized because the Watt unit was named after a person.
KWH
If a unit uses 1,000 Watts in 1 hour, it is said to have an energy rating of 1kWh.
MODULATING FURNACES
Furnaces are designed to deliver maximum heat for comfort on the coldest of days. In most cases, those days account for fewer than three percent of winter days. The rest of the time, your furnace is providing more heat than necessary. Because conventional furnaces are either providing no heat, or at full capacity, the temperature in your house goes up and down by several degrees, adversely affecting your comfort and your energy bills. Modulating furnaces solve this problem by varying the amount and temperature of air delivered between different capacities, so that the air flowing out of the registers is always at the temperature you determine. This results in lower operating costs, more comfortable temperatures throughout the house and quieter operation.
PACKAGE UNIT
Equipment in which all heating and cooling components are located in one cabinet. Installed either beside or on top of a home or business.
REFRIGERANT
The liquid used to absorb and transfer heat from one part of the home comfort system to another.
REFRIGERANT LINES
Copper lines used to transfer the refrigerant between the outdoor unit and the indoor unit.
SEER
Seasonal Energy Efficiency Rating. Used to express the efficiency of an air conditioning unit, or a heat pump in cooling mode. The higher the SEER rating, the more efficient the unit. The Department of Energy minimum is 13 SEER.
SPLIT SYSTEM
A home comfort system that uses an indoor and an outdoor component to deliver comfortable air to a living environment.
SRN
The Air Conditioning and Refrigeration Institute performs tests and assigns a Sound Rating Number (SRN) to units. A lower SRN rating indicates a quieter unit with average SRNs of between 74dB and 80dB.
THERMOSTAT
A temperature-measuring device used to control the operation of home comfort systems to maintain a comfortable temperature within the house. Programmable thermostats allow you to program different temperatures for different times of the day.
TON
The ton ratings you see here have nothing to do with the weight of the unit. In fact a ton is simply 12,000 BTUs (see BTU definition on this page). A typical home cooling/heating system uses heat pumps or air conditioners with a capacity of between 1.5 and 5 tons.
UPFLOW
A term used to describe the direction of airflow through a furnace. An upflow furnace takes return air from the bottom, heats it, and then delivers the warm air from the top.
WATT/WATTS
Electrical power, also expressed as ‘W’. For example, a 100W globe consumes 100 Watts of electrical power. The W in Watt is always uppercased, because it is named after a person.
ZONE/ZONING
A home may be divided into several different areas, or zones, to better control the temperatures throughout the house. The process of dividing your home into different zones is called zoning.
Quick Picks
The Basics Typically installed in the garage,
basement or attic, tank-type water heaters use propane, natural gas or
electricity to produce a large volume of dependable, low-cost hot
water. Residential tank-type water heaters typically store between 20
and 80 gallons of hot water, usually at the factory setting of 120°F.
The temperature can be adjusted up or down by a control on the unit.
If there is high demand over a short period—a family taking
back-to-back showers in the morning or a vacation home packed with
guests—the hot water can run out. When it does, you have to wait for
the water to get hot again. Though they're well-insulated, to
compensate for standby heat loss, tank-type water heaters heat water
even when not in use.
Options Abound When choosing a replacement to a
tank-type water heater, many people replace it with the same thing.
However, advancements in efficiency and technology have made the
decision a little more challenging. A new 30-gallon water heater may
produce more hot water than a 40-gallon water heater built just 10
years ago. The easiest way to tell is to compare the amount of water
both units produce in the first hour (typically listed as FHD or First
Hour Delivery on the specs for the water heater). Tankless water
heaters offer continuous hot water, but if a remodeling budget is
tight, a tank-type water heater will likely be the most affordable
choice. Tank-type installation is fast and labor costs are
minimal—typically between $500 to $1,000. Upgrading a standard 5' x 9'
bathroom to a master suite or an in-home spa may require upgrading to
a larger gallon capacity unit, especially if the new bathroom will
include a deep soaking tub with a multi-head shower system.
Safety First Current gas hot water heaters contain
special flammable vapor ignition resistant (FVIR) technology that
prevents the ignition of flammable vapors, such as spilled gasoline,
outside the unit. First unveiled by Rheem® in 2003, the proprietary
Guardian FVIR System incorporates an exclusive air and fuel shutoff
mechanism that shuts the water heater down quickly and safely should
vapors ignite within the combustion chamber. In addition, the Rheem
Guardian System is maintenance-free, with no filters to clean—ever.
Learn more about Rheem tank-type water heaters. Learn more
The Basics Tankless water heaters are more energy
efficient than conventional tank-type water heaters because they
provide hot water on demand at the precise temperature needed, so
there is no storage and therefore no need to expend energy heating
that stored water. About the size of a medicine cabinet, these
space-saving, compact models can easily be wall-mounted indoors and
even outdoors, depending on the climate.
More Hot Water, Fast Many homeowners complain that it
takes a long time to get hot water. That’s caused by the hot water
between the water heater and the faucet going cold. You have to get
that water, which can be up to two gallons out before hot water starts
flowing. To solve that, you can install a tankless water heater with a
built-in or accessory recirculation pump, which circulates hot water
through your pipes so it’s ready when you need it. Another option is
to install a tankless electric tankless model, which can be installed
at or near the point of use for near-instant hot water.
Continuous Hot Water, Continuous Savings Rheem
tankless water heaters combine innovative technology and functionality
for a hot water solution that can supply a continuous flow of low-cost
hot water whenever and wherever you need it. No matter how many body
sprays and showerheads, no matter how deep the whirlpool, you will not
run out of hot water with a properly sized tankless water heating
system. In addition, the Rheem Guardian System is maintenance-free,
with no filters to clean—ever. Learn more
Solar water heaters are an even greener hot water solution that uses a
dark-color solar collector to capture the solar energy that is used to
heat the water. Solar water heating systems can be “passive,” where
the water flows between the collection area to the storage tank via
gravity or some other non-mechanical means; or “active,” which uses a
circulating pump to move water through the system. An active system
may also be called “forced circulation,” and requires more energy than
passive systems.
Even the most efficient solar water heaters sometimes require some
auxiliary heating (boosting). This may be because of a large,
late-in-the-day hot water usage or after a long period of extensive
cloud cover. An electric, gas or other fuel-type booster can be quite
effective in enabling a solar water heater to provide a year-round
supply of steaming hot water, but it also obviously adds more energy
requirements.
Both types of water heaters have their benefits. See the full
comparison below to decide which type of Rheem® water heater is right
for your lifestyle and budget.
Tankless Features
✓ Continuous hot water✓ High energy efficiency✓ Compact, space-saving design✓ Electronically controlled✓ Exclusive sensing burner technology✓ Exclusive film wrap overheat protection✓ Digital thermostat with self-diagnostic program✓ Precise t"emperature control✓ Consistent hot water supply temperature✓ No hot water storage✓ Low operating costs✓ Low NOx emissions – all models✓ Indoor or outdoor models available✓ Two high-altitude options: up to 6,560 or 9,840 ft. elevations
Tank-Type Features
✓ Low initial cost✓ Low venting cost✓ Large variety of sizes available✓ Flow rates of 12 GPM and up✓ High altitude installations to 10,000 ft. elevation✓ Low- or ultra-low-NOx emissions on select models
Sizing is the technique that matches the capacity of the hot water source to your needs. For tank water heaters, the key criterion is hot water storage capacity. For tankless water heaters, the key criterion is hot water flow rate. Incoming water temperature is a critical consideration, which varies by region and season. That is, a water heater in the North—either tank or tankless—will need a higher BTU input in the winter than the summer to heat and deliver water to a given temperature. Regardless of which type of water heater is used, you should start with a lifestyle audit of your typical usage:
Hot Water Usage Audit Questionnaire
Baths: How many bathrooms are in the house?
Showers: How many showers are in the house and how many showerheads, body sprays and side sprays are in each shower? How much water do they use? Standard showerheads have a flow rate of 2.5 gallons per minute, although new water-efficient showerheads have lower flow rates. Most people are comfortable showering in water temperatures around 102°F to 106°F.
Bathtubs: How many bathtubs and whirlpools are in the house? How many gallons are needed to fill each to capacity? While small tubs are usually about 40 gallons, deep soaking tubs can hold up to 140 gallons. As with showering, remember, most people bathe at temperatures between 102°F to 106°F.
Schedules: What is the typical bathing and bathroom use schedule in the home? How many occupants are likely to be bathing simultaneously?
Other hot water appliances: Are any other hot water appliances in use at the same time? If so, these need to be calculated also, e.g., dishwasher, hot-water laundry, kitchen use, etc.
Geography: Where is your home? Consider the winter inlet water temperatures in the area to make sure there’s sufficient hot water flow on the coldest days. The rule of thumb is:
40°F for the northern tier of states.
50°F in most parts of the South.
60°F year-round in Southern California, the Southwest and Gulf states.
Do the math; select the right unit: Add up your peak demand in gallons per minute and see which size of tank water heater will satisfy this peak requirement at the very coldest time of the year; i.e., when the difference between the inlet and outlet water temperatures will range as high as 75°F if you live in the Northeast or Upper Midwest. For example, if a Minneapolis homeowner picks a system that will handle a Delta T of 75°F in the winter (45°F inlet to 120°F outlet) to meet the needs of a household that runs two showers simultaneously every weekday morning, this consumer need not worry about the summer, when the inlet temp should be 20°F to 25°F warmer.
While tankless water heaters do not run out of hot water, if not sized correctly, the flow rate of that water can be adversely impacted. The temperature of the shower will remain the same, but flow could slow to a trickle. So the first step in sizing tankless water heaters is to add up all the flow rates of showerheads, faucets and appliances that are likely to be in use at the same time. Step two is to consider the incoming water temperature. When inlet water temperatures dip down into the 30s and 40s, larger BTU inputs will be needed. In certain high-volume applications, you may want to specify more than one tankless water heater unit, either installed separately or connected together to operate as a single tankless system.
The Rheem EZ-Link™ technology will facilitate this application.
What’s the Difference Between High Efficiency (EF) Ratings and the New Uniform Energy Factor (UEF)? If you’ve ever researched water heaters before a purchase, then you’ve probably compared high efficiency, mid-efficiency and standard efficiency information. To help consumers in their water heater purchase decisions, the Department of Energy has developed new industry standards. Beginning, June 12, 2017, EF ratings have been replaced with the new industry standard for measuring energy efficiency in water heaters called, Uniform Energy Factor (UEF). The new UEF rating method improves the industry’s ability to:
• Define consistent standards for measuring energy efficiency performance
• Simplify the water heater selection process
• More accurately reflect real-world scenarios that impact energy efficiency ratings
• Enable apples-to-apples water heater comparisons across brands What Energy Efficiency Rating Factors Have Changed? The new UEF standard affects more than just the efficiency number itself. Adjustments in new DOE testing procedures now impact water heating performance stats associated with the amount of hot water produced in a real-world situation to the length of typical showers. Examples of Performance Factors Impacted by UEF include:
• First Hour Rating / First Hour Delivery (FHR / FHD) – The amount of hot water a waterheater can provide in the first hour of operation. Updated testing procedures result ina more accurate representation of performance.
• Capacity – Previously, capacity was expressed as a single number that didn’t fullyrepresent the actual storage capacity of the water heater. With the UEF regulations,the DOE now requires manufacturers to inform buyers of both a water heaters’nominal capacity by gallon grouping (40, 50, 60 gallon, etc.), as well as the actualstorage capacity (35, 37, 42, 58 gallon).
• Estimated Energy Cost Savings – The updated testing procedures enable a moreaccurate approximation of what it will cost to run a particular water heater.
If you already own Rheem® water heating equipment, you may need to
know the serial number for service, warranty information or other
reasons. The serial number identification on all Rheem water heating
product rating labels contain ten (10) digits.
Your warranty is based on the date of manufacture and the warranty
code listed in the model number. To verify if your water heater is in
warranty you can call 1-800-621-5622 and listen for the prompt to take
you to warranty.
Glossary of Terms
Anode Rod
Because water heater tanks are typically made of steel, they are (or should be) equipped with an anode rod that attracts the minerals in water so they attack the sacrificial rod instead of the tank.
Atmospheric
A type of gas water heater that uses no fans or other assistance to vent flue gases.
Booster
As the water inside a standard tank-type water heater is used, the temperature of the hot water that comes out becomes lower. A booster is a type of tankless water heater that measures the water exiting the tank water heater and heats it.
BTU
Short for British Thermal Unit. The amount of heat required to raise or lower the temperature of one pound of water by one degree Fahrenheit.
BTU/h
The heat transfer rate of water heating equipment is measured in British Thermal Units per Hour.
Capacity
The capacity of a water heater is how much hot water it can store. New rules mandate that two numbers are quoted for capacity: the nominal capacity (typically 30 gal., 40 gal., 50 gal. etc.) and the rated capacity, which is the actual amount of water a water heater can hold (typically 2-5 gallons lower than the nominal capacity).
Dip Tube
The dip tube is on the cold water line of a water heater to direct the cold water to the bottom of the tank both so it can force the hot water out and so it can be heated.
Direct Vent Water Heater
A direct vent water heater gets its combustion air from the outside, rather than the room the water heater is installed in.
EF
Short for Energy Factor, this is a measure of how efficiently a water heater uses its energy input. The higher the number, the more efficient the unit is. EF has been replaced by Uniform Energy Factor.
Expansion Tank
Installed on the water inlet line, an expansion tank regulates the pressure in water lines.
FVIR
All residential water heaters manufactured after 2003 are required to be Flammable Vapor Ignition-Resistant, that is they must not ignite flammable vapors outside the combustion chamber.
Hybrid Water Heater
A hybrid water heater uses heat pump technology to draw heat from the air and transfers it to the water to make it hot. This type of water heater is highly efficient.
NOx
As fossil fuels are burned, oxides of nitrogen are often formed. Because these combustion by-products impact air quality, EPA regulations control the acceptable amount of NOx output of most water heaters.
Point-Of-Use Water Heater
These electric water heaters are compact enough to be installed at or near the place they will be used. They heat water only when it is needed and return to standby when hot water is no longer need. Depending upon the capacity (or flow rate in the case of tankless), point of use water heaters can supply hot water to a sink, an entire bathroom, an addition, a workshop, garage, etc.
Standby Losses
Standby losses measure the temperature loss in a hot water tank over a 24- hour period and are report as an energy loss in BTU/h units.
T&P Valve
An important safety measure, the temperature and pressure (T&P) valve opens when the temperature or pressure inside the water heater exceeds its designed limits.
UEF
In 2017, EF ratings were replaced with the Uniform Energy Factor (UEF), a new industry standard for measuring energy efficiency in water heaters. The new UEF rating method defines consistent standards for measuring energy efficiency performance,simplifies the water heater selection process and more accurately reflects real-world scenarios that impact energy efficiency ratings.
Watt/Watts
Electrical power, also expressed as ‘W’. For example, a 100W bulb consumes 100 Watts of electrical power. The W in Watt is always uppercased, because it is named after a person.