1. [Home](/) 2. [Guides](/guides/) 3. [Furnaces and winter heating in Southwest Ohio](/guides/furnace-guide/) 4. Repair or replace an aging furnace? # Repair or replace an aging furnace? There is no single number that decides it. Age, repair history, efficiency, safety, and comfort all count, and a good contractor will walk through them with you instead of pushing one answer. ## Key takeaways - Furnace age is a starting point, not a verdict. Many furnaces run for roughly 15 to 20 years, depending on the equipment and care. - A single minor repair on a furnace in decent condition is usually reasonable. Repeated repairs or a failed major component change the picture. - A cracked heat exchanger or other safety failure is a strong reason to stop using the furnace. - Replacement is a good time to look at ductwork, thermostat, and equipment options. ## Start with age and condition Furnaces do not expire on a date, but many last somewhere around 15 to 20 years. Installation quality, maintenance, and how hard the system works all affect that. A furnace past that range is more likely to fail and harder to find parts for, and its efficiency is probably lower than what is available now. The model and serial number on the data plate often show the manufacture date. A HVAC contractor can read it and tell you where your furnace stands. Age matters most in combination with condition. A 12-year-old furnace that was never maintained may be in worse shape than a well-kept one that is older. Rust, soot, water stains around the vent, and repeated ignition problems all suggest a system that is wearing out. In a Southwest Ohio basement, moisture is worth noting, since damp air can speed up corrosion on cabinets and venting. ## Look at the repair history One repair is not a pattern. A failed igniter, flame sensor, or capacitor on an otherwise healthy furnace is a normal part of owning one, and replacing the part is often the sensible choice. A pattern is different. If you have had service calls in several recent seasons, if each fix is followed by a new problem, or if you are being told that more parts are likely to fail soon, you are putting money into equipment that is near the end of its life. Ask the contractor which part failed, whether it is likely to fail again, and what else they saw during the visit. Ask whether the repair is covered by any warranty that is still in force. A clear answer to each of those is more useful than a general recommendation. Repairs for common problems are covered under [furnace repair](/services/furnace-repair/). ## Efficiency and AFUE AFUE shows how much of the fuel a furnace turns into usable heat over a season. Older standard-efficiency furnaces are commonly around 80 percent or lower, and condensing models are rated 90 percent or higher. If your furnace is old, its actual efficiency may be below its original rating. Moving to a higher-AFUE furnace can reduce the fuel needed for the same heat, which matters more in a home with high heating use. The benefit depends on the rest of the house. Leaky ducts, poor insulation, and air leaks around rim joists and attics all limit what any furnace can do. Condensing furnaces need a drain for condensate and plastic venting, which affects installation, especially in older homes with chimneys. A contractor can explain what your house would need. Efficiency alone seldom justifies replacing a working furnace, but it adds weight when other factors point the same way. ## Safety comes first Some problems are not a repair-or-replace judgment at all. A cracked heat exchanger can let combustion gases, including carbon monoxide, into the air stream. Depending on the furnace and the extent of the damage, repair is often not practical, and many contractors will tag the furnace out of service. Do not keep running a furnace that has been condemned. Other safety concerns include a corroded or blocked flue, repeated flame rollout, and gas valve problems. These are jobs for a licensed professional, not for a home fix. Whatever you decide, keep carbon monoxide alarms working on every level of the house. They are a backup for the equipment, not a substitute for inspection. ## Comfort and the bigger picture Ask how the home feels, not just how the furnace runs. Cold rooms, noise, dry air, and long recovery times after a cold night may be signs the furnace is the wrong size, the ducts are undersized or leaking, or both. Replacing a furnace without addressing them carries the same complaints into the new equipment. Before you decide, ask the contractor to: - explain what is wrong and what each option would fix; - perform a load calculation instead of copying the old unit's size; - check the ducts and venting; - discuss options such as a heat pump or a dual-fuel setup, which may suit some homes (see [heat pumps](/services/heat-pumps/)); - give you the options in writing. A contractor who explains the tradeoffs and lets you take time to decide is a better partner than one who rushes you. If you are weighing a specific situation, the [furnace guide](/guides/furnace-guide/) and [contact](/contact/) are good places to start. ## Frequently asked questions How do I find out how old my furnace is? Look for the data plate inside the furnace cabinet. The model and serial numbers usually encode the manufacture date, and a HVAC contractor can decode it for you. Should I replace the furnace and air conditioner together? Not always. They share the blower and ductwork, and matching equipment can perform better, but the right answer depends on the age and condition of each. A contractor can look at both and explain the options. What if my furnace was condemned for a cracked heat exchanger? Do not use it. Cracked heat exchangers can leak carbon monoxide into the home. A professional can explain whether any repair is possible, and if not, your choice is between replacement options. 3 min read. ### Want us to handle it? Comfort Solutions works in Lebanon, Maineville, Mason, Morrow, Waynesville, Franklin, Springboro, Monroe. [Get a quote](/contact/)[Call (513) 932-7200](tel:+15139327200) ### More in this guide - [Furnaces and winter heating in Southwest Ohio](/guides/furnace-guide/) - [Furnace warning signs to take seriously](/guides/furnace-guide/furnace-warning-signs/) - [Furnace filters: which one and how often](/guides/furnace-guide/furnace-filters/) ### Related services - [Tune-Ups & Maintenance Plans](/services/maintenance/) - [Heat Pumps](/services/heat-pumps/) - [Furnace Repair & Replacement](/services/furnace-repair/) ### Service areas - [Lebanon](/areas/lebanon/) - [Maineville](/areas/maineville/) - [Mason](/areas/mason/) - [Morrow](/areas/morrow/) - [Waynesville](/areas/waynesville/) - [Franklin](/areas/franklin/) - [Springboro](/areas/springboro/) - [Monroe](/areas/monroe/) ### Other guides - [Air conditioning through an Ohio summer](/guides/air-conditioning-guide/) - [Heat pumps, humidity and indoor air quality](/guides/heat-pumps-and-air-quality-guide/) ## Call (513) 932-7200 or send a quote request, and we will go over your system with you. [Get a quote](/contact/) [Call (513) 932-7200](tel:+15139327200) --- **Comfort Solutions** · 118 W Main St Suite B, Lebanon, OH 45036 · (513) 932-7200 · info@comfort-solutions.net [Get a quote](/contact/) · [Services](/services/) · [Guides](/guides/) · [FAQ](/faq/)