Your furnace should be able to heat your Harrisburg, PA home evenly and consistently. If you are dealing with cool spots, fluctuating temperatures, or heat that simply feels insufficient, the system may need attention. Wear, age, airflow issues, and neglected maintenance can all limit heating performance. Here are 10 common reasons why your furnace may struggle to keep you warm.
With proper installation and maintenance, gas furnaces usually last 12 to 20 years. Electric furnaces often last 20 to 30 years because they do not deal with combustion stress. When a furnace nears the end of its lifespan, efficiency naturally drops, and the system has a harder time producing and distributing heat. If your furnace is approaching two decades of use and can no longer keep up, replacement is often the best solution.
Your furnace may be working correctly, but your home may be losing heat through air leaks. Warm air escapes through unsealed windows, doors, gaps in construction, and poorly insulated attics. Adding weatherstripping, insulation, and caulking gaps can dramatically improve comfort and lower heating costs.
Your furnace relies on your thermostat for accurate instructions. If the thermostat cannot read the room temperature correctly, your furnace may not turn on when needed. During a tune-up, HVAC technicians test, clean, and calibrate thermostats and check wiring for faults.
Programmable and smart thermostats typically last around 10 years. Older models can drift out of calibration. Upgrading your thermostat ensures better accuracy and more reliable heating.
Proper furnace sizing requires a Manual J Load Calculation. If your home has been remodeled, expanded, or significantly changed since the furnace was installed, your current unit may no longer match your heating needs. An undersized furnace cannot keep up, while an oversized furnace will short-cycle and heat unevenly. A sizing assessment can help restore proper comfort.
Clogged air filters restrict airflow and force the furnace to work harder. Most standard filters need replacement every 30 to 60 days. Dirty filters can cause overheating, poor airflow, and short cycling. If you struggle to remember replacements, a smart thermostat can remind you when it is time.
The National Air Duct Cleaners Association recommends cleaning ducts every three to five years, while the EPA recommends cleaning on an as-needed basis. Pest debris, dust buildup, and airflow blockages can reduce heating performance.
Signs you may need duct cleaning include:
During a tune-up, technicians also check for duct leaks. If your ducts lack insulation or have gaps, sealing and insulating them can improve airflow and heating efficiency.
A yearly tune-up is essential for safe and efficient operation. Technicians clean the system, check safety controls, lubricate moving parts, and catch early problems. If you skipped pre-season maintenance, lack of care may be holding your system back.
The heat exchanger moves heat from combustion into the air your furnace blows into your home. Temperature stress, age, or poor maintenance can cause cracks.
Common symptoms include:
A cracked heat exchanger is a serious safety issue and requires immediate service.
Closing vents may seem like a way to redirect heat, but it creates pressure imbalances that strain the furnace. Too much static pressure can cause overheating, short cycling, and reduced airflow. Make sure every vent is open and clear of furniture, rugs, or other blockages.
The limit switch prevents overheating by shutting the furnace off when temperatures rise beyond safe levels. If it malfunctions, it may shut the furnace down prematurely. If your furnace turns off before heating your home, the limit switch may need repair or replacement.
Ready & Able Plumbing, Heating & Air proudly serves Harrisburg and nearby communities. Since 1998, we have provided trusted furnace installation, repair, and maintenance services. We offer convenient scheduling and preventative maintenance plans to keep your heating system in top condition. If your furnace is struggling to warm your home, our team will find the cause and fix it. Contact Ready & Able Plumbing, Heating & Air today to schedule furnace service in Harrisburg!