Frequently asked questions.

Heating Systems

What is Precise Comfort technology?
Precise Comfort technolgy is an operating and control system that allows a furnace to automatically adjust airflow and heat output in increments as small as 1% to match a home's precise comfort requirements. It operates like your car's cruise control, making small, seamless adjustments to meet varying demand, all while improving overall efficiency.

What is AirFlex technology?
AirFlex technology allows your Lennox dealer to adjust the G71MPP's heating, cooling and fan-on mode blower settings to accommodate your lifestyle, home design and geographic location. For example, your dealer can choose a setting that increases airflow during fan-on operation to compensate for cathedral ceilings or long duct runs. If you live in a humid climate, your dealer may choose a slower fan-on setting that helps minimize off-cycle re-humidification.

The G71MPP furnace claims to be the "quietest furnace you can buy." Other furnace manufacturers make similar claims. Whose claim do I believe?
The next time you see another manufacturer's furnace claiming to be the "quietest," you'll likely also see the claim fails to reference what unit was tested, how it was tested or by what standard it was tested. All Lennox sound claims include a disclosure explaining what Lennox product was tested, as well as the testing standard used.

Every time my current furnace cycles on, I hear a rush of air that's so loud, it wakes me from my sleep. Does the G71MPP solve that problem?
Yes. The G71MPP's variable speed motor slowly - and quietly - ramps up to speed, with no sudden rush of air. It ramps down slowly, too, and either cycles off or continues running in a slow, quiet fan-on mode.

Does the G71MPP work in a dual-fuel application?
Yes. Increased system efficiency is possible when you pair the G71MPP gas furnace with an electric heat pump. This dual-fuel combination helps control heating costs by seamlessly alternating between the two energy sources, depending on outdoor conditions and prevailing energy costs. The G71MPP's energy-efficient blower motor helps control cooling costs, too.

Can the G71MPP help reduce contaminants in my home's air?
Yes. When you set your thermostat to "FAN," the G71MPP is able to continuously maintain a slow circulation of air throughout your home. That constant low-speed fan operation increases the effectiveness of your indoor air quality products such as filters and germicidal lights, allowing them to capture and remove more contaminants.

What is a heat pump?

A heat pump is an all-in-one heating and air conditioning system that works year-round to keep you comfortable. During warmer months, a heat pump works as a normal air conditioner. It extracts heat from inside the home and transfers it to the outdoor air. In colder weather, however, the process reverses: the unit collects heat from the outdoor air and transferring it inside your home. Even when the air outside feels extremely cold, the air still contains some heat. The heat pump pulls the heat from this cold outdoor air and sends it inside to warm your home. When there's not enough heat in the outside air to meet the demand of the thermostat setting, an electric heater supplements the outdoor air to warm the home. Extremely efficient, this process produces two to three times more heat than the energy it uses. Also, a heat pump can be an effective add-on option to use in conjunction with an existing gas furnace. With this dual-fuel option, the two systems share the heating load, but never function at the same time. Each system operates when it is most cost effective. The heat pump will be the primary heating and cooling system. However, when the temperature drops below the heat pump's ability to operate as efficiently as the gas furnace, the gas furnace will take over until the temperature rises enough for the heat pump to operate more efficiently. To learn if a dual-fuel system is right for your home, contact us.

What is two-stage heating?

Two-stage heating means the furnace has two levels of heat output: high for cold winter days and low for milder days. Since the low setting is adequate to meet household-cooling demands 80% of the time, a two-stage unit runs for longer periods and provides more even heat distribution.

Longer, low-capacity operation has many advantages:
Consistent comfort Two-stage heating eliminates the temperature swings associated with standard furnaces, regulating temperature to within as little as one degree of the thermostat setting. Quiet operation Two-stage furnaces start in the first stage, when the amount of heat required is lower, instead of reaching full capacity all at once. That means there's no sudden "kick" or blast of air.
Improved air filtration Low-speed operation allows your filters to capture more contaminants (because air is constantly passing through them), so you can breathe easier. Efficient performance Because the furnace operates mostly in its lower-capacity first stage, it burns less fuel than a standard furnace that always runs at full capacity and shuts off when the heating demand has been met.

Can I use my chimney with my new furnace?

Furnace technology has advanced significantly in recent years, raising concerns over chimney use. As a result of changing technology, many existing masonry chimneys aren't able to meet the specific demands of new furnaces.

There are several reasons for this furnace-chimney incompatibility. First, the size of the chimney can be an issue. Modern, higher-efficiency furnaces transfer more heat into your home and less heat up the chimney than older, less-efficient units. While this means more efficiency for your energy dollar, it also means that the existing chimney might be too large for the new furnace. The result could be improper ventilation of flue products, which can cause condensation problems inside the chimney.

Other considerations include chimney height and location, proper lining and condition of the chimney. Building codes must also be kept in mind to ensure proper draft in the chimney for adequate ventilation. For the best advice on how to configure your new furnace, contact your local Lennox dealer. Click here http://www.lennox.com/pdfs/wgya/11K81%20Chimneys.pdf for more information.

What are furnace ratings?

Furnaces are rated by the Annual Fuel Utilization Efficiency (AFUE) ratio, which is the percent of heat produced for every dollar of fuel consumed.

Like the miles-per-gallon rating on your automobile, the higher the AFUE rating, the lower your fuel costs. All furnaces manufactured today must meet at least 78% AFUE. If your furnace is 10 to 15 years old, it very well may fall below the current furnace minimum and waste energy.

This doesn't mean that you should only select a furnace based on its AFUE rating. The efficiency rating is just one factor to consider when looking for a new furnace.

Furnaces use electricity to run fans and motors. The amount of electricity used varies greatly depending on the type of furnace. Be sure to check electricity usage prior to making a purchase decision.

What is a variable speed furnace?

The term "variable speed" refers to the furnace's indoor blower motor, which moves at different speeds to precisely control the flow of heated and cooled air throughout your home. Better airflow control has several benefits:
Electrical efficiency

Variable speed motors can actually save you money on your energy bills, as they consume less electricity than standard motors.
Cooling efficiency

Variable speed technology also means you will gain heating efficiency or AFUE.
Zoning

Variable speed motors are excellent for zoning, which allows you to customize your comfort in different areas of your home and control your energy bills.
Air quality

A variable speed motor can also help clean the air in your home. When the fan is in constant operation (indicated by the "Fan" setting on your thermostat), the motor will continue to slowly circulate air, allowing filters to capture more contaminants.
Humidity control

A variable speed motor combined with a ComfortSense 7000 Series Touchsreen Thermostat allows you to control the amount of humidity in your home for improved indoor air quality and comfort.

What is SilentComfort technology?

Until recently, noisy furnaces were accepted as the norm. High noise levels were associated with heating your home. But today's technology allows you to choose a furnace that is not only highly efficient but also exceptionally quiet. Sound is measured in decibels (dB). A decibel describes the relative loudness of a sound. Although no financial savings are tied to it, sound rating of a heating system can directly affect your comfort. Your ears tell you what is too noisy and what seems quiet. Most heating systems manufactured today are quieter than those produced in past years. But there is still a great difference in the sound levels of products on the market today. At Lennox, we don't believe that you can ever be too comfortable in your own home. If you cherish the idea of a quiet day or evening at home, you'll appreciate the calm composure of Dave Lennox Signature Collection furnaces, designed with exclusive SilentComfort Technology. For example, the Lennox G71MPP Variable-Capacity Gas Furnace is at least 50 percent quieter than competitor's furnaces, making the G71MPP the quietest furnace you can buy. SilentComfort is achieved by utilizing variable-speed technology. In other words, this furnace has a high and low speed. Since the low speed setting is adequate to meet household-heating demands approximately 80 percent of the time, the furnace is much quieter than a conventional single-stage furnace. In addition, the variable-speed motor ramps up gradually, eliminating the sudden "kick" or blast of air upon startup. Unlike other furnaces, the gas burners are contained within a patent-pending sound enclosure. Special sound-absorbing insulation has been added to the cabinet to further reduce the operation noise. With the new Dave Lennox Signature Collection furnaces, designed with exclusive SilentComfort technology, sound is no longer a barrier to home comfort. Your local Lennox Dealer can show you additional benefits of owning the quietest furnace you can buy.

Why should I zone my house?

A zoning system is designed for the many ways you use your home. Maybe you're caught up in family "thermostat wars?" Or perhaps you have unoccupied areas that do not need conditioning? A Lennox zoning system allows you to divide your home into separate areas, giving you the comfort and control you've always wanted.

The main benefits of residential zoning are:
Comfort Zoning meets the specific temperature and airflow requirements of one area, without affecting other areas. EfficiencyA properly designed zoning system can save you hundreds of dollars in energy costs each year. Control Zoning divides the home into different areas and comfort into different levels, giving you more choices and control than ever before. Quiet Performance When integrated with variable speed and/or two-stage HVAC systems, zoning allows your heating and cooling equipment to deliver peak performance and efficiency without continually operating at peak capacity. Lower speeds mean lower sound levels.

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Will my new furnace work differently than my old one?

Furnace technology has advanced significantly in recent years. Modern furnaces are designed to provide more even and efficient heating than past furnaces, which can impact both how your system operates and what you notice about your system.

To better regulate temperatures and airflow, modern furnaces move more air over the heat exchanger than older furnaces. The air that comes out of your furnace registers may not seem as warm as the air from your old furnace, but overall airflow is improved. Better airflow means higher comfort.

Also, new furnaces are designed to integrate with high-efficiency air conditioners, so furnace blowers are more powerful to accommodate add-on cooling. Since cold air is much heavier than warm air, your system needs an extra boost from the blower to deliver cool air throughout your home. If you have an older home, this performance boost could produce unfamiliar sounds because air duct systems were originally designed for heating only. To minimize sound levels, choose a variable speed product which automatically changes speeds to meet the airflow needs of both heating and cooling cycles.

When replacing the outdoor unit, should the indoor unit also be replaced?

The answer is most likely YES, but this is mainly due to four main reasons:

1. Matched system design

All outdoor cooling units are specifically designed to work with matched indoor units for optimum efficiency and performance. Air conditioner and heat pumps may "work" with other indoor units, but the result is a definite compromise in overall system performance.
2. Design advances

In recent years, indoor blower coil units have undergone numerous design advances especially in the areas of air handling performance, filtering efficiency and operating sound levels. A new outdoor unit will also include the latest design advances.
3. Higher cooling and heating efficiency

The cooling and/or heating efficiency rating assigned to a given air conditioner or heat pump is based on matched system performance. While you may gain higher efficiency by replacing only the outdoor unit, the efficiency levels (and savings) will not be as high as with a matched system.
4. Equipment age

If an air conditioner or heat pump outdoor unit is 10 years old and needs to be replaced, the indoor unit is just as old and has been subjected to the same amount of wear and tear. Replacing both units means you won't have to replace the indoor unit in a short time—you'll have years of service from both units.

New warranty

A new unit also gives you a new product warranty. Replacing the indoor unit at the same time as the outdoor unit gives you added peace of mind, knowing the new warranty covers the entire system.
Cost savings

At first, replacing only an air conditioner or heat pump outdoor unit may appear to be a bargain. That is, until you consider the lower efficiency, decreased reliability and high cost of ownership associated with single-unit replacement. It may cost more to replace an entire system, but this gives you more efficiency, reliability and comfort.

How can I confirm the model and serial numbers for my heating system?
You can find the model and serial numbers (M/N and S/N) for your furnace by removing the top-front service panel and looking to the left side of the interior cabinet or the top of the blower deck, depending on whether your system is an 80% or 90% AFUE unit. Also, the orientation (horizontal or vertical) and flow direction (down or up) of your furnace may impact the location of the information. To view a diagram, click here.