Each gas furnace model has an energy efficiency rating in the form of a percent. This number is its Annual Fuel Utilization Efficiency (AFUE), or the ratio of annual heat output of the furnace compared to the amount of annual fuel energy it consumes. For example, if a furnace has an AFUE of 80%, it means 80% of the energy in the fossil fuel is being converted to heat while 20% escapes and is wasted.1
The initial cost of a high-efficiency condensing furnace can be more expensive than a less efficient model. According to The Department of Energy, homeowners will likely save more money on fuel bills over the life of a high AFUE product when compared to a lower AFUE or less efficient gas furnace. 1 However, when determining if a higher-efficiency furnace is cost-effective for your budget, homeowners should evaluate their anticipated length of home ownership to determine how long it would take to recuperate initial costs of a higher AFUE model.
Additionally, many states and utilities offer tax credits and other incentives to homeowners who install high-efficiency furnaces. An experienced local dealer can assist you in determining whether a higher efficiency gas furnace or a mid-efficiency model is right for your needs.
The Federal Energy Management Program (FEMP) provides acquisition guidance for residential furnaces, a product category covered by ENERGY STAR. Federal laws and requirements mandate that agencies purchase ENERGY STAR-qualified products or FEMP-designated products in all product categories covered by these programs and in any acquisition actions that are not specifically exempted by law.
FEMP's acquisition guidance for residential furnaces and the associated ENERGY STAR efficiency requirements apply to natural gas, propane, and oil-fired furnaces with heating capacities less than 225,000 Btu/h.
The U.S. Environmental Protection Agency (EPA) provides residential furnace program requirements and efficiency criteria on the ENERGY STAR website. Manufacturers meeting these requirements are allowed to display the ENERGY STAR label on complying models. Federal buyers can use ENERGY STAR's list of certified residential furnaces to identify or verify complying models.
FEMP has calculated that the required ENERGY STAR-qualified residential furnace saves money if priced no more than $1,275 (in 2019 dollars) above the less efficient model. The best available model saves up to $1,550. Table 1 compares three types of product purchases and calculates the lifetime cost savings of purchasing efficient models. Federal purchasers can assume products that meet ENERGY STAR efficiency requirements are life cycle cost-effective.
Calculated based on January 2021 ENERGY STAR efficiency levels; values shown are rounded to the nearest dollar. Federal agencies must purchase products that meet or exceed ENERGY STAR efficiency levels.
An efficient product is cost-effective when the lifetime energy savings (from avoided energy costs over the life of the product, discounted to present value) exceed the additional up-front cost (if any) compared to a less efficient option. ENERGY STAR considers up-front costs and lifetime energy savings when setting required efficiency levels. Federal purchasers can assume ENERGY STAR-qualified products and products that meet FEMP-designated efficiency requirements are life cycle cost-effective. In high-use applications or when energy rates are above the federal average, purchasers may save more if they specify products that exceed federal efficiency requirements (e.g., the best available model).
Products meeting ENERGY STAR or FEMP-designated efficiency requirements may not be life cycle cost-effective in certain low-use applications or in locations with very low rates for electricity or natural gas. However, for most applications, purchasers will find that energy-efficient products have the lowest life cycle cost.
These mandatory requirements apply to all forms of procurement, including construction guide and project specifications; renovation, repair, energy service, and operation and maintenance (O&M) contracts; lease agreements; acquisitions made using purchase cards; and solicitations for offers. Federal Acquisition Regulation (FAR) Part 23.206 requires agencies to insert the clause at FAR section 52.223-15 into contracts and solicitations that deliver, acquire, furnish, or specify energy-consuming products for use in federal government facilities. To comply with FAR requirements, FEMP recommends that agencies incorporate efficiency requirements into technical specifications, the evaluation criteria of solicitations, and the evaluations of solicitation responses.
In the warmer U.S. South region where space heating requirements are less, a special ENERGY STAR logo is used to identify furnaces that qualify at the lower efficiency level. Residential furnaces with the U.S. South region ENERGY STAR labels cannot be sold in the U.S. North region.
All models that meet the ENERGY STAR product specifications are \"condensing\" furnaces. This technology takes advantage of normally exhausted heat in the furnace's flue gas to improve efficiency. When installing condensing furnaces, select products that feature sealed combustion. Condensing furnaces should not use indoor air for combustion. Indoor air frequently contains contaminants from common household products and can cause corrosion that damages condensing furnaces. Furnaces with sealed combustion have supply lines that bring outdoor air directly to the combustion chambers.
In addition to improving efficiency, condensing furnaces with sealed combustion are safer. The supply lines, combustion chambers, and flues are sealed from the inside of homes thus preventing exhaust gases from leaking or being back-drafted into occupied spaces. Due to these features, condensing furnaces require slight modifications with installation and are usually more expensive than standard-efficiency models; however, their increased efficiency means they are typically life cycle cost-effective.
An efficient furnace will not save energy or money if it is not properly installed. Federal procurement officials and buyers should require that gas furnaces be installed in accordance with the ENERGY STAR Quality Installation (QI) guidelines. Installation problems like oversizing, poorly designed distribution systems, and leaky ducts result in efficiency losses, occupant discomfort, and shortened equipment life. Requiring the contractor to follow the QI guidelines will ensure that these and other problems are addressed and the expected energy and cost savings are achieved.
Properly sealing the building envelope and weather-stripping doors and windows can result in additional savings and may allow for the use of a lower-capacity furnace, resulting in even further savings. Consider leaving your furnace off during unoccupied hours or using a programmable thermostat to minimize unnecessary operation. Regular maintenance is necessary to maintain peak performance.
Furnaces heat air using fuel, electricity, or both, and then move the heat through ducts and, ultimately, throughout your house. High-efficiency furnaces are better at transferring the heat generated into your house, with as little air wasted as possible. They require less energy to run than traditional furnaces.
Some high-efficiency furnaces will also have more demanding maintenance needs than traditional furnaces. In general, with any type of furnace, you should definitely turn to a professional for maintenance services.
In order to choose the best furnace for your home, you have to take your own needs, priorities, and circumstances into account. This can include the size of your home, the weather where you live, and what your budget is.
What is the best forced-air furnace to buy This expert, unbiased furnace buying guide will help you choose between the major brands to find the right heater for your home and budget.
Obviously, if you can squeeze more efficiency out of your heating and cooling equipment, you can make a major dent in your monthly energy bills. If you intend to stay in your home for a few years, upgrading from an old, inefficient furnace to a new, high-efficiency model can pay for itself and improve your comfort.
In an effort to curb energy waste and pollution, the U.S. Department of Energy (DOE) instituted standards for manufacturers at the beginning of 1992 that required every new furnace to turn at least 78 percent of its fuel into heat. On May 1, 2013, these minimums rose to 80 percent. All new models sold must meet or surpass this; efficiencies climb as high as 98.5 percent with the best models.
As minimums rise, these descriptions become even less meaningful. Just pay attention to the percentage. And be aware that, depending upon where you live, it may not be worth it to spend the big bucks for the highest efficiency unit available. Though these units usually make sense in cold climates, the savings might not pencil out if you live in a mild-winter climate.
Furnaces designed specifically for use in a mobile home will have slightly lower minimums. Where they are installed will also affect the regulations: All non-weatherized furnaces installed in the northern United States must have at least a 90 percent AFUE.
Many gas-fired, high-efficiency furnaces also save on the electricity required to power the blower motor, though this savings is not factored into the AFUE rating. They do this by coupling a sophisticated, programmable thermostat to a variable-speed motor.
A key feature to look for when buying a condensing gas furnace is a long-term warranty on the heat exchanger; the best types are built to resist the corrosive effects of moisture and chemical buildup for the life of the house.
For example, the Lennox SLP98V, which has up to 98.2 percent AFUE, automatically adjusts the speed to match the heating requirements, captures maximum heat with a stainless-steel secondary heat exchanger, and can interact intelligently with a thermostat for optimal efficiency. 59ce067264