HVAC replacement planning: costs, tax credits, and the $5,000 rule explained

February 9, 2026

If your furnace limped through winter or your AC struggled last summer, late winter is the right moment to plan a replacement before spring demand spikes. A thoughtful plan can save you money, reduce downtime, and help you capture current incentives.

This guide breaks down typical price ranges for furnace and AC combos by home size and efficiency, the factors that drive costs, how to apply the $5,000 rule for repair vs. replacement, and what to know about federal tax credits. You will also see why booking now sets you up for a smooth spring install.

Modern Heating & Plumbing serves Northern Illinois and Southeast Wisconsin with free estimates, a three-year labor warranty on new HVAC installations, and financing on approved credit. We help you compare options clearly and choose with confidence.

What a replacement typically costs

Prices vary by brand, home layout, and local codes, but here are realistic starting ranges for a complete gas furnace plus central AC replacement, including standard installation. Use these as directional guides, then confirm with a tailored quote for your home.

Small homes or townhomes, roughly 1,000 to 1,500 sq. ft.: $8,500 to $12,500 for a matched 80 to 96 percent AFUE furnace and 13.4 to 15.2 SEER2 AC
Mid-size homes, roughly 1,600 to 2,200 sq. ft.: $10,500 to $16,500 for a 90 to 96 percent AFUE furnace and 14.3 to 17 SEER2 AC
Larger homes, roughly 2,300 to 3,000+ sq. ft.: $13,000 to $22,000+ for a higher capacity, 95 to 98 percent AFUE furnace and 16 to 20 SEER2 AC

A high-efficiency paired system usually costs more upfront but can lower utility bills and improve comfort and sound levels. Complex duct modifications, electrical upgrades, condensate drainage changes, and local permit requirements can add to the total.

What drives the price

Understanding the cost drivers helps you prioritize what matters most.

Efficiency ratings: SEER2 for cooling and AFUE for gas furnaces are the big variables. Higher ratings improve energy performance and can qualify for incentives, but raise equipment cost.
System size and staging: Correct BTU sizing and equipment type, single-stage, two-stage, or variable-speed, affect both comfort and price. Variable-speed systems modulate output, which often delivers the best comfort and quiet operation.
Ductwork condition: Leaky, undersized, or unbalanced ducts can undermine any new system. Sealing, resizing, or adding returns increases cost but often pays back in comfort and efficiency.
Electrical and refrigerant line requirements: Newer outdoor units sometimes need dedicated circuits or updated line sets. Condenser pad, surge protection, and disconnect upgrades can be required by code or best practice.
Venting and condensate: High-efficiency furnaces need PVC venting and proper condensate drainage. Basements and finished spaces can add complexity.
Permits and code compliance: Local inspection and permit fees vary. Professional load calculations, test-out documentation, and thermostat upgrades can also be part of a code-compliant install.

The $5,000 rule, explained

The $5,000 rule is a quick way to decide whether to repair or replace older equipment. Multiply the repair cost by the system age in years. If the result is more than $5,000, replacement usually makes better long-term sense.

Example: An 11-year-old furnace needs a $600 repair. 11 x $600 equals $6,600, which suggests replacement is worth considering. This rule does not replace a full evaluation, but it helps you weigh recurring repairs, declining efficiency, and the value of a warranty-backed new system.

How long HVAC systems last

Lifespans vary by maintenance and usage, but most central AC units and gas furnaces last around 10 to 15 years. With regular maintenance, some systems reach 15 to 20 years. If your unit is in that range and repairs are becoming frequent, a planned replacement before failure can prevent an uncomfortable outage.

Best time to buy and schedule

Late winter through early spring is often the best window to buy and schedule a replacement. You will have better appointment availability, time to compare options, and a smoother installation experience before the first warm spell. When the first hot days arrive, lead times can increase quickly.

A quick word on federal tax credits and rebates

At a high level, many high-efficiency HVAC upgrades can qualify for federal incentives under current programs, including certain ENERGY STAR certified heat pumps, central air conditioners, furnaces, and advanced controls. Incentive amounts and product qualification criteria can change and depend on the exact model ratings, such as SEER2, EER2, AFUE, and capacity thresholds.

Because tax situations are personal and incentives evolve, confirm eligibility with your accountant and review local utility programs for possible rebates or low-interest financing. Our team can provide model specifications and documentation so your tax professional can verify credits for your household.

Planning your replacement in three practical steps

Get a load calculation: Proper sizing ensures comfort, efficiency, and equipment longevity. Avoid one-size-fits-all tonnage guesses.
Compare two or three matched systems: Look at total installed price, SEER2 and AFUE ratings, stage or variable-speed operation, sound ratings, and warranty coverage. Ask for an apples-to-apples comparison.
Address the duct system and controls: Sealing, balancing, and a modern thermostat can unlock the full value of a new system.

Why choose Modern Heating & Plumbing

We have served the community since 1948 with a focus on safety, quality, and clear communication. For replacements, we offer free estimates, a three-year labor warranty on new HVAC installations, and financing on approved credit. Our technicians are factory trained, follow code requirements, and complete post-installation testing so your system runs as promised.

If you are in or near Antioch, explore our local service details for HVAC and plumbing support, including scheduling for late winter consultations. Many homeowners also use this time to review indoor air quality options like whole-home filtration and duct cleaning. You can learn more about IAQ solutions and duct services in our Indoor Air Quality section, which includes guidance for duct cleaning in Gurnee and nearby areas.

Learn about service options in your area and request a free estimate in Antioch at our local page for HVAC Antioch: https://www.modernheatingco.com/plumbing-heating-and-cooling-in-antioch-il
Explore whole-home air quality and related services, including duct cleaning options here: https://www.modernheatingco.com/indoor-air-quality

FAQ: quick answers to common questions

What is the average cost to replace a residential HVAC system? Many homes fall between $10,000 and $18,000 for a matched furnace and AC with standard installation, with small homes sometimes lower and large homes higher. Ductwork, electrical, venting, and efficiency upgrades can add to the total.
What is the $5,000 rule for HVAC? Multiply the repair cost by the system age. If that number is over $5,000, replacement often makes more sense than another repair, especially for older, less efficient equipment.
Is my HVAC eligible for a tax credit? Some high-efficiency systems qualify, but it depends on exact performance ratings and current federal rules. Confirm with your accountant, and check state or local utility rebates as well.
What is the best month to buy an HVAC system? Late winter or early spring often provides better availability and time to compare options before the warm-weather rush.
How many years will an HVAC last? Most furnaces and central AC units last 10 to 15 years, sometimes longer with consistent maintenance.

Ready to plan before the spring rush

A well-planned replacement balances upfront cost, energy savings potential, and comfort. Start with a professional evaluation, compare a few right-sized options, and confirm which incentives apply to you. If you are in Northern Illinois or Southeast Wisconsin, Modern Heating & Plumbing is ready to help with free estimates, a three-year labor warranty on new HVAC installations, and financing on approved credit. Schedule your late winter visit now so your home is ready for the first warm days of spring.

For homeowners in Waukegan considering a full system upgrade or controls, you can also review our local service hub for HVAC and plumbing support here: https://www.modernheatingco.com/plumbing-heating-air-conditioning-in-waukegan-il

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Winter Boiler Check: Safety, Service, And When To Repair Or Replace

January 8, 2026

Winter in Northern Illinois and Southeast Wisconsin pushes your boiler hard. When the temperature drops and lake effect winds pick up, you need steady, safe heat. A quick winter check can prevent a mid-season breakdown, protect your home from leaks or carbon monoxide risk, and keep energy costs under control. Here is how to approach boiler safety, what a professional inspection includes, and how to decide whether to repair or replace before deep winter sets in. Why annual boiler service matters in peak season Heating demand is highest in winter, which exposes weak parts and small issues that went unnoticed in fall. Annual service helps you avoid surprise shutdowns and keeps your boiler operating within manufacturer specifications. A tuned boiler runs more efficiently, distributes heat evenly to radiators or in-floor loops, and reduces stress on pumps and valves. It also verifies safety controls are functioning, which is essential with gas appliances. If you have not scheduled this year’s maintenance, do it now to catch small problems before they become big ones. Modern Heating & Plumbing offers a 24/7 answering service so you can reach us when you need to, and our technicians service most boiler makes and models. What a professional boiler inspection consists of A thorough boiler inspection is systematic and safety focused. Expect your technician to cover: Combustion analysis: Measures combustion efficiency and checks for excess carbon monoxide in the flue, ensuring proper fuel-to-air ratio. Venting check: Confirms vent pipes are clear, pitched correctly, and sealed, including termination points that can ice up in winter. Heat exchanger condition: Looks for cracks, corrosion, or scaling that can reduce efficiency or allow flue gases to mix with indoor air. Pressure, expansion tank, and relief valve: Verifies system pressure, confirms the expansion tank is accepting volume changes, and tests the pressure relief valve. Pumps, valves, and air separators: Inspects circulator pumps, zone valves, check valves, and air elimination devices for noise, wear, or leaks. Safeties and controls: Tests low-water cutoff, flame sensor, ignition system, high-limit switch, and thermostat communication. System water quality: Checks for sludge, rust, or mineral content that can cause noisy operation and reduced heat transfer. Radiators or in-floor zones: Evaluates balancing, purges air if needed, and confirms consistent temperatures across zones. That checklist identifies performance issues and safety risks, and it gives you a clear plan for any needed repairs or adjustments. Signs your boiler needs servicing now Call a professional if you notice: New or worsening noises, such as kettling, banging, grinding, or persistent whooshing. Odors, especially a sulfur or metallic smell, or any suspicion of gas. If you smell gas, leave the home and call your utility, then call us. Leaks or frequent pressure drops, visible water around the boiler, or water staining below piping. Inconsistent heat, cold spots, radiators that do not warm evenly, or zones that short cycle. Pilot or burner trouble, repeated resets, yellow or unstable flames, or ignition failures. Rising energy bills without a clear reason. Frequent top-offs on older systems or air in radiators that keeps returning. These are red flags that can point to unsafe operation or a pending breakdown. Prompt attention is cheaper and safer than waiting. How often should a boiler be inspected? Plan on a professional inspection once a year. The best timing is early fall for proactive care, but mid winter inspections are still valuable if you missed the preseason window. Homes with older boilers, multi zone systems, or hard water may benefit from checkups every 6 to 9 months, especially if you have had recurring issues. Can you service a boiler yourself? Short answer, no for anything gas or combustion related. Testing safeties, tuning combustion, and opening fuel components require specialized tools and training. DIY mistakes can lead to carbon monoxide exposure, gas leaks, or water damage. You can safely do a few small tasks, like keeping the area around the boiler clear, checking radiators for air, and noting pressure on the gauge. Leave diagnostics, gas work, venting, and internal repairs to a licensed technician. What is the typical lifespan of a boiler? Many residential boilers last around 15 years with proper maintenance. Some cast iron units can last longer with consistent water quality and timely repairs. Signs you are nearing the end include frequent breakdowns, rising energy use, part obsolescence, and heat exchanger deterioration. A well maintained, correctly sized replacement can lower utility costs, improve comfort across zones, and reduce repair stress during winter. Repair or replace, how to decide Use these practical tests: Age and repair history: If your boiler is 12 to 20 years old and has needed multiple repairs in the last two winters, discuss replacement. Safety or heat exchanger issues: Cracks, severe corrosion, or repeated flue gas concerns generally justify replacement. Efficiency and comfort: If energy bills keep rising, zones are uneven, or the unit short cycles, a right sized, modern boiler can deliver better comfort at a lower operating cost. Parts availability: When critical parts are difficult to source or backordered, proactive replacement protects you from mid season downtime. A technician can run the numbers on repair costs versus replacement value and help you compare options, including potential incentives and financing. Preparing your home before the tech arrives Clear a path to the boiler and main mechanical room. Note any recent noises, leaks, or odor events, including when they occur. List every thermostat or zone and describe how each is performing. Locate past service records or warranty information if available. This speeds up diagnostics and ensures nothing important gets missed. Why homeowners choose Modern Heating & Plumbing Since 1948, our team has served Northern Illinois and Southeast Wisconsin with straightforward recommendations and careful workmanship. We install, repair, and maintain boilers across homes and light commercial spaces, and we stand behind our work. You get a 24/7 answering service to reach us anytime, factory trained technicians, and clear guidance on repair versus replacement. If a new system is recommended, ask about boiler financing in gurnee to spread costs on approved credit. If you are comparing local providers for combined heating and plumbing support, our technicians also handle broader home needs across the region. Explore our full service capabilities for hvac antioch or schedule an estimate if you are planning ahead. Ready to schedule, here is your next step Do not wait for a cold snap to find a weak link in your heating. Call Modern Heating & Plumbing at 847-782-9690 to schedule your boiler inspection or repair. Ask about maintenance plans to keep your system on track and financing if replacement is advised. If you manage commercial properties, we also perform Gurnee commercial boiler repair and installation with minimal downtime. Summary Annual professional boiler service improves safety, efficiency, and winter reliability. A full inspection includes combustion analysis, venting checks, heat exchanger evaluation, pressure and expansion tank review, pump and valve testing, and safety control verification. Call now if you notice noises, odors, leaks, inconsistent heat, or frequent resets. Do not DIY gas or combustion work, keep the area clear and let a pro handle the rest. Most boilers last around 15 years, with repair or replacement guided by age, safety, efficiency, and parts availability. We are here to help you stay warm and safe all winter. Reach out today to get your boiler ready for the cold.