The decision to buy a new furnace often comes at the worst possible moment: It's midwinter and freezing outside and your old furnace decides to kick the bucket. You don't have a lot of time to shop around for the best value on a new model. Instead, you're at the mercy of your local HVAC contractor and whatever is available to install on short notice. But with a little forethought and planning, you can take much of the stress out of buying a cheap furnace and save a lot of money in the process.
Cheap Furnaces Buying Guide
The average furnace has a lifespan of 15 to 20 years, so if yours is approaching that age, you might want to have it checked and stash some money away for an eventual replacement. Plan to replace your furnace in the off-season -- spring or fall -- when heating-and-cooling contractors have more time and flexibility. You may be able to negotiate better prices, especially on installation and service warranties. You can get estimates from several local contractors and have time to weigh your options. (Note: Unless you're well-trained, never attempt to install a new furnace yourself. Doing so incorrectly can put you and your family at risk for carbon monoxide poisoning. A DIY job could also mean forfeiting the warranty.)
The good news is that cheap furnaces now are significantly more energy efficient than even 10 years ago. So, while you'll take a hit initially by replacing your old unit, you'll save money in the long run on your energy bills. For instance, if your furnace has a 60% efficiency rating (as many older models do), a new 80% efficiency furnace will cut your monthly gas bill by about 30%. A cheap furnace with 90% efficiency can potentially cut your gas bill in half, so you should recoup the investment if you plan to live in your home a while longer. Plus, if your replacement furnace carries an Energy Star label (meaning its efficiency is 85% or higher), you may also qualify for a tax break or rebate.
There are several types of furnaces designed for different home sizes, efficiency levels, and fuels. Most modern American homes use natural gas furnaces (which this article focuses on), though some feed on oil or propane. An older home might have a wood or pellet furnace. In most cases, the furnace also uses electricity to power a fan or blower, which moves the heat through ducts in the walls.
If you're unsure what kind of cheap furnace you need, the nameplate on your current furnace should tell you the fuel type, efficiency rating, and how much heat the unit produces, either in British thermal units (BTU) or watts/kilowatts (W/kW). That number has to do with the size of your home and the energy required to heat the space. A 1,500-square-foot home might need a 60,000-BTU furnace, for example. Most furnaces top out at about 100,000 BTU. Very large homes may have multiple heating and cooling zones with a furnace for each zone.
Some of the most popular furnace brands on the market today are Trane, Rheem (which also makes Ruud), Carrier (which also makes Bryant), Lennox, Tempstar, Goodman (Amana), and Coleman. Experts at Galt Technology and HVAC-Talk point out that although there are differences among these brands, most furnace manufacturers use the same suppliers for major parts, such as heat exchangers and blower motors, as well as electronic circuit boards. As a result, experts suggest looking at the overall repair record for each brand, as well as the reputation of the installer and the warranty, before making a final choice.
You'll find cheap furnaces ranging from $1,000 to $3,000; high-end furnaces can cost $5,000 or more. Note that these prices are just for the unit and do not include installation, which raises the cost. The price will also vary depending on your home size. To get the most accurate furnace price, have an HVAC contractor come to your home and give you a quote.
The biggest difference between a cheap furnace and a pricey one is the efficiency rating. Higher-end furnaces also have bells and whistles such as variable-speed blowers (cheap furnaces tend to have one or two speeds, whereas premium furnaces have more than two) and fancier air filters. More expensive furnaces, if sized and installed correctly, also tend to run more quietly than budget models.
In this buying guide, we've outlined the major features to consider when buying a cheap furnace and provided some reviews and comments about certain brands. Unlike with other products, such as TVs, we can't recommend specific models. The new furnace you choose will depend on the size of your house, the fuel source, and your energy needs. However, we can offer general performance feedback about certain series of cheap furnaces, based on the assessments of experts and customers who have used the units in their homes.
The cheap furnaces we admire most are the popular and highly recommended Trane XL80 Series (starting at $1,600) and the Carrier Infinity Series (starting at $2,500). The Carrier Infinity 96 is the only unit we found in this price range that carries the Energy Star label. We also like the Lennox Merit Series (starting at $2,000) for its solid reputation and positive expert feedback, as well as the extremely affordable Payne gas furnaces (starting at about $1,115), which carry long warranties. The reliability of Goodman furnaces (starting at $1,500) seems to have improved in recent years, but we're still reluctant to recommend the brand; experts note that it will take a while to see whether these furnaces can stand the test of time.
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Features Comparison Buying Guide continues below table
In addition to being more energy-efficient, new cheap furnaces have desirable features such as variable-speed blowers and multistage heating, improved air filtration systems, and the ability to attach to a digital thermostat. Expert sources such as Galt Technology, HVAC-Talk, and Consumer Reports explain the most important factors to look at when buying a natural gas furnace. Here's what they have to say:
High-Efficiency Furnaces.For most gas furnaces, the annual fuel utilization efficiency, or AFUE, reflects the percentage of the fuel that's converted to heat, with the rest cast off as waste. A 90% AFUE furnace converts 90% of the gas to heat, wasting only 10%. Units with 80% AFUE, such as the Payne PG8MEA (the series starts at about $1,115) and the Trane XL80 Series (starting at $1,600), convert 80% of the fuel and send 20% into the atmosphere. A natural gas furnace with 90% AFUE will set you back $1,000 or so beyond what you'd spend on a similar-size 80% AFUE unit, but the higher AFUE will save you more on energy costs and also produce less pollution. Some furnace brands, such as the mid-range Lennox Signature Series (starting at $4,400) offer better than 90% AFUE, as does one of our picks for best gas furnace, the Carrier Infinity 96 high-efficiency furnace (the Infinity Series starts at $2,500).
The general rule of thumb is to buy a furnace with as high an AFUE rating as you can afford because you'll reap the benefits on your monthly utility bills. This is especially true if you live in a cold climate with harsh winters. If your winters are relatively mild, an 80% AFUE furnace will work nicely and still operate much more efficiently than the old model you're replacing. If you live in a very cold region, it's better to opt for a furnace with an AFUE of 90% or higher, along with a variable-speed blower. A high-efficiency furnace will keep the temperature in the house more constant, put less stress on the furnace parts, and waste less energy. (See the next page for more on the benefits of variable-speed blowers.) If you can't decide how efficient a furnace you need, don't be afraid to ask your installer to calculate the estimated fuel costs for both efficiency ratings, using your current energy bill for reference.
Energy Star Furnaces.In addition to a high efficiency rating, an energy-efficient furnace can also earn an Energy Star label from the federal government. This distinction means that the furnace meets guidelines set up by the Environmental Protection Agency and Department of Energy for conserving energy and reducing pollution. In general, oil and gas furnaces have to have AFUE ratings of 85% or higher to qualify as Energy Star furnaces. The Carrier Infinity 96 gas furnace, with its 96% AFUE, is one high-efficiency furnace that carries the Energy Star rating. Bonus: You can get tax breaks for replacing old appliances with new Energy Star models, so ask your tax preparer whether your new high-efficiency furnace qualifies.
Digital Thermostats.Most new furnaces, including all the cheap natural gas furnaces on our list, can be connected to a digital thermostat. Using a digital thermostat, especially one that is programmable, can cut your heating bills even further because the temperature control is more precise. You can program a digital thermostat to automatically lower the temperature at night or when you're at work so you don't have to remember to make the adjustment every day.
Gas Furnace Size.In the world of furnaces, size matters. A cheap gas furnace that doesn't generate enough British thermal units (BTU) or watts/kilowatts (W/KW) or has a blower that's too small won't keep your house warm enough on the coldest days. On the other hand, a gas furnace that's too large will cycle on and off more frequently, putting more wear on the internal components, wasting energy, and causing big, uncomfortable temperature swings. Moreover, if your furnace is too big for your air ducts, it could exacerbate the normal noise level associated with furnaces by forcing too much air through the ducts. (A lot of the negative consumer reviews complaining about noise can be attributed to improper furnace size.) So what size furnace should you get? To ensure the best fit, ask your installer to determine the correct furnace size using a standard calculation such as those found in the Air Conditioning Contractors of America's Manual J (commonly called a "Manual J Calculation" or "J-analysis"). These calculations take into account the climate where you live, along with the size, design, and construction of your house.
Variable-Speed Blowers and Variable Heat Output.Old furnaces typically blow air at only one temperature and one speed. But new, more efficient furnaces offer variable-speed blowers and multi-stage burners. The Trane XL80 Series, for example, offers two-stage heat output, while the Carrier Infinity Series goes a step further, offering more speeds and heat levels. Payne gas furnaces (starting at about $1,115) and the Lennox Merit Series (starting at $2,000) also offer variable speed blowers, although the exact specs weren't found. In milder weather, cheap gas furnaces with variable speed and heat output blow out less heat at a slower speed. But when the temperature drops, the furnaces kick up the speed and deliver more heat. These features prevent the furnace from always cycling completely on and off, allowing for more even heating and reducing wear and tear on the unit. A cheap gas furnace that's not always running at full force is quieter and more energy efficient.
Air Filtration.If you suffer from dust allergies, asthma, or other lung problems, you'll want to pay close attention to the type of air filtration that's built into a discount furnace. Some premium furnaces offer electrostatic filters, while others have high-efficiency particulate air (HEPA) filters, which reduce the amount of dust that is blown through the heating system. If your lungs aren't sensitive, however, experts at Consumer Reports argue that this expensive feature is unnecessary. Instead, just change out your furnace's filter monthly and try to reduce allergens (such as pet dander and dust) in your home. If you're not that compulsive, make sure to change the filter at least once a year.
Warranty.Most cheap gas furnaces come with a warranty for parts (typically five to 10 years) and a separate warranty for the heat exchanger (10-plus years). Some manufacturer warranties are more generous than others. For instance, Lennox offers a five-year warranty on parts, as does Trane, while Carrier and Payne cover parts for 10 years. Carrier offers a lifetime warranty on the heat exchanger; Payne and Trane offer 20-year warranties. Be sure to register your new gas furnace with the company to take full advantage of any furnace warranties. Your installer should also guarantee the workmanship with a service warranty, which could range from six months to a couple of years. Unlike the manufacturer's warranty, the contractor's warranty is negotiable.
Consumer and expert furnace reviews of specific models are scant, partly because of the vast array of furnace sizes and types available, but also because it can take a decade or more to properly develop a furnace review that evaluates how well a unit performs and how reliable it is. That said, some sites do comment on furnace brands in terms of their overall performance and reliability and provide some furnace reviews. Here's what we found:
Overall Performance and Reliability.As long as you don't live in an extremely cold region, you can't beat the Trane XL80 series of mid-efficiency (80% AFUE) furnaces, one of our picks for best furnaces, according to experts at Galt Technology. Furnace reviews by consumers and HVAC experts at FurnaceCompare.com seem to agree, noting that most problems with Trane furnaces come from mistakes during the installation process. In a survey by Consumer Reports, Trane furnaces have a slightly better service and reliability history than most other furnace brands.
Older high-efficiency furnaces produced by Carrier were the subject of a now-settled class action lawsuit, which asserted that a critical component in the furnace (the condensing heat exchanger) was manufactured with inferior materials and failed before the end of its expected 20-year lifespan. However, new Carrier furnaces (sold after 2008) are not part of the complaint, nor were less efficient Carrier models (with an AFUE lower than 90%). A contractor who posted a furnace review at FurnaceCompare.com installs many Carrier Infinity 96 units and says he always trusts and recommends them because they last a long time with no trouble.
Payne furnaces impress the team at WebHVAC, which says the brand has a superior track record in reliability and performance and is backed by one of the best warranties in the business. While consumer reviews are mixed at FurnaceCompare.com, a couple of contractors posting furnace reviews say installation is most likely to blame for recurring problems. One reminds consumers that furnaces, like cars, need regular maintenance to keep running smoothly.
Lennox earns reasonably good appraisals across the board on the furnace reviews site FurnaceCompare.com. Its Merit series is certainly the most affordable, and users posting on GardenWeb forums say these furnaces do what they're meant to do. But if you can afford to spring for the Lennox Elite Series (starting at $4,200), you'll get a much higher AFUE rating (up to 92%) and could save money on monthly heating bills over the years.
Goodman furnaces (starting at $1,500) came under fire several years ago when a comparative furnace ranking of repair histories by Consumer Reports (based on reader responses to a survey) indicated that Goodman units were less reliable than 10 other major furnace brands. However, Goodman seems to have corrected many of the problems, according to forum users and new customers posting furnace reviews on GardenWeb and FurnaceCompare.com. Still, experts note that more time is needed to assess the reliability of the new Goodman models, and Ask Me Help Desk suggests springing for an extended warranty if you buy a Goodman furnace.
Furnace Installation.Other performance characteristics, such as noise level and comfort/temperature, are difficult to assess because they are heavily dependent on how the furnace is installed and whether it's the correct size for the house. Homeowners occasionally comment on these matters in gas furnace reviews, but because of the inherent differences among houses and installers, we determined that such remarks are not particularly helpful when you're deciding which furnace to buy.
Indeed, the HVAC contractor you use can have the biggest effect on the performance of your furnace. Talk with friends and co-workers or ask your local gas utility for recommendations, then crosscheck those recommendations against consumer reviews of the contractor at online review sites such as YellowPages.com and ServiceMagic. If you have the time, get estimates from a few different contractors. Any contractor you use should be able to show you proof of bonding and insurance, plus any required contractor's licenses and certifications by trade organizations, such as the North American Technician Excellence or HVAC Excellence.
Remember, getting the most efficiency and comfort from a cheap furnace also depends on the duct work and weatherproofing around your home. Ask your installer to check your ducts for any leaks and to seal them up, and take measures to reduce drafts around your home with techniques such as weather-stripping or upgrading to better doors and double-pane windows.