U.S. government mandates set higher efficiency standards to make today’s furnaces surpass yesterday’s units. Those operating at 55- to72-percent AFUE (annual fuel utilization efficiency) have been obsolete since 1992. You should replace a non-compliant furnace with one meeting the latest 80-percent AFUE minimum or better. In 2013, that new guideline superseded 1992’s 78-percent standard. If your existing system has a post-1992 installation date, it’s inadequate if it’s operating at or below 78-percent AFUE.

The lifespan of a properly maintained furnace averages 15-25 years. When you need to replace the unit that heats your interior living spaces, an HVAC professional will base your installation estimate on your home’s size, configuration, and age. Understanding key considerations like BTU (British thermal unit) and load calculations will help you get a new heating system that’s more efficient and cost-effective.

BTU Calculation by Home Size

Price differences among available heating capacities may stretch into the thousands, so choosing one that exceeds your home’s size greatly could squander more than $10,000. But selecting a furnace that’s not large enough to fulfill your household’s needs will make it run constantly. That much overuse can raise your utility bills with costly repairs or replacement occurring earlier than customary.

Your home’s average heating capacity depends on its square footage. For a typical dwelling, each square foot needs 30-60 BTUs. Your climate zone determines if your property requires less or more BTUs. In warmer climates, 30-35 BTUs will heat a conventional residence. For comparison, most houses in cold climates need 50-60 BTUs.

Lower BTU ranges can be sufficient for remodeled and newer premises that have better insulation than older properties. So for a 2500-square-foot home in a warm climate, multiplying 2500 by 30 equals 75,000 BTUs. To contrast that rate for a cold climate, multiply 2500 by 50 to get 125,000 BTUs.

Unfortunately, a 100,000-BTU furnace won’t necessarily heat a home requiring that BTU amount appropriately. You also must account for the unit’s AFUE rating. So a unit with an 80-AFUE ranking will push only 80,000 BTUs or 80 percent of its 100,000-BTU full capacity into your house.

Use standard efficiency calculations to discover if a system can heat your residence sufficiently. First, convert its AFUE rating into a percentage. Then multiply that number by the furnace’s BTU rating. The result is the BTUs available to heat your home. So for an 80-AFUE rating, multiplying 80 percent by 100,000 BTUs gives you 80,000 BTUs. Multiplying a 90-AFUE-rated unit’s 90 percent by 125,000 BTUs results in 112,500 BTUs.

Load Determination

Some contractors use a Manual J or load calculation to recommend the right furnace size more precisely. Your area’s building permit policy may require that step. A load calculation involves this data:

• Roof type and color
• Window numbers, types, and locations
• Exterior door quantities, styles, and placements
• Foundation type
• Insulation values
• House size and location
• Home’s direction or orientation
• Main construction materials
• Ideal temperature for your house to maintain
• Landscaping affecting sun and wind amounts hitting your home

Installation Process

Professional furnace installation isn’t a quick and simple task lasting just one or two hours. Two careful installers can spend eight hours removing your old unit and putting in your new one. Additional crucial phases include venting, drainage, and electrical and gas hookups. So hiring experienced and reliable pros is vital. After a sloppy installation, all you can expect from an ideal furnace is two decades of lousy performance.

Replacing heating systems is one of Cooper Climate Control’s specialties. We’ll install a furnace from a top heating manufacturer like Carrier, Goodman, Lennox, Rheem, Trane, and York. Most units come with five-year guarantees on parts and lifetime warranties on heat exchangers. GE Capital offers affordable financing with monthly payments starting at just $39. Contact Cooper Climate Control to apply for a Home Climate credit card so your replacement furnace cost will fit into your budget.

Benefits of Upgrading

A furnace predating 1992 most likely is wasting at least 30 percent of your heating expenses while polluting the atmosphere with as much as 4 tons of carbon dioxide annually. While offering eco-friendly advantages over older versions, today’s furnaces also run more quietly. A new model will provide better efficiency, saving money on utility bills over time. Your gas company might even offer a rebate if you move up to a more energy-efficient replacement model.