15 Expert Signs It’s Time to Replace Your Furnace
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Is your home not staying warm like it used to? Are your heating bills creeping higher every winter? These could be signs that your furnace is no longer performing the way it should. While minor furnace problems can often be resolved with a repair, there comes a point when a furnace replacement is the smarter and safer choice.
At A2B Plumbing and Heating, we’re trusted experts in diagnosing, repairing, and replacing heating systems across the Lower Mainland.
Below are 15 clear warning signs that it might be time to upgrade your home comfort system and replace your furnace with a high-efficiency model.
Table of Contents
1. Your Furnace Is Over 15 Years Old
Most furnaces are built to last 15 to 20 years with regular maintenance. After that, even if it still runs, performance and reliability start to drop.
Here’s why age matters:
Worn-out components like the heat exchanger, blower motor, or control board are more likely to fail.
Efficiency declines, meaning your furnace uses more energy to produce the same amount of heat.
Older models lack modern features, such as:
Variable-speed motors
Sealed combustion for safety and efficiency
Smart thermostat compatibility
If your furnace was installed before 2010, it’s likely outdated and costing you more in energy and repairs. Planning a replacement now can prevent a no-heat emergency later.
2. Your Heating Bills Are Rising
Have your gas or electricity bills been creeping up even though your usage hasn’t changed? That’s a red flag your furnace is losing efficiency.
Here’s what’s likely happening:
Worn-out components force the system to work harder and run longer to reach your set temperature.
The AFUE (Annual Fuel Utilization Efficiency) rating drops over time, meaning more fuel is wasted.
Older furnaces lack energy-saving tech like modulating burners or high-efficiency blowers.
In many cases, upgrading to a modern, ENERGY STAR®-rated furnace can lower your monthly bills significantly while also reducing your carbon footprint.
3. You’re Dealing with Frequent Repairs
If you’ve called a technician multiple times in the past two winters, your furnace may be on its last legs.
Common signs of a failing system include:
Repeated issues with the blower motor, ignition system, or heat exchanger
Frequent error codes or safety shutoffs
Parts that are increasingly hard to source or replace
A good rule of thumb: If repair costs are more than 50% the price of a new furnace, it may be more cost-effective to replace your furnace with a new high-efficiency unit professionally installed by A2B Plumbing and Heating.
4. Uneven Temperatures Throughout the House
Are some rooms too hot while others stay cold even with the furnace running? That’s a common sign your system isn’t distributing heat properly.
Possible causes include:
Aging or undersized furnace that can’t push heat evenly
Worn-out blower motor struggling to move air through the ducts
Leaky or unbalanced ductwork causing inconsistent airflow
Modern high-efficiency furnaces, especially variable-speed models, are designed to deliver even heat throughout the entire home even in multi-level or larger spaces. If your comfort depends on wearing a sweater in one room and a t-shirt in another, it’s time to consider an upgrade.
5. Your Furnace Struggles to Start or Stay On
If your furnace struggles to start, shuts off too soon, or runs non-stop without reaching the desired temperature — something’s wrong.
These issues often point to serious internal problems:
Failing ignition system or worn igniter
Malfunctioning control board or temperature sensors
Cracked heat exchanger triggering safety shutoffs
Short cycling, where the furnace rapidly turns on and off
These symptoms cause excess wear, increase energy costs, and often lead to complete system failure if not addressed. If your furnace can’t maintain a steady heating cycle, it’s a strong sign that replacement is the safer long-term choice.
6. Constantly Adjusting the Thermostat
If you’re always tweaking the thermostat to stay comfortable, your furnace may be struggling to keep up.
Here’s what might be causing the issue:
Inaccurate or failing temperature sensors
Leaky ductwork that lets warm air escape before it reaches rooms
An undersized furnace that can’t meet your home’s heating demands
A weak blower motor failing to circulate air effectively
These problems lead to inconsistent temperatures, poor comfort, and wasted energy. Upgrading to a modern furnace that’s smart thermostat compatible gives you precise control, improved efficiency, and a much more consistent indoor climate.
7. Strange Noises: Rattling, Popping, or Screeching
Furnaces should be heard, not noticed. If yours is making odd noises, it’s time to pay attention.
Different sounds point to different problems:
Rattling: loose screws, unsecured panels, or deteriorating internal parts
Popping: ducts expanding or contracting due to uneven heating
Screeching: worn blower bearings or a frayed motor belt
These noises often start small but get worse over time and can signal imminent system failure if ignored.
A quiet, well-functioning furnace is a sign of health. If your system is sounding off, it may be time to replace it before it breaks down completely.
8. Yellow or Flickering Pilot Light
A properly working gas furnace should have a steady blue flame. If you see a yellow, orange, or flickering flame, it means something’s wrong.
This could indicate:
Incomplete combustion, which reduces efficiency
Dirty or misaligned burners
Poor ventilation or limited air intake
A cracked heat exchanger, which can leak dangerous gases
A discoloured or unstable flame isn’t just a performance issue it’s a serious safety hazard and a potential carbon monoxide risk. If you notice this, shut off the furnace and call a licensed HVAC technician immediately.
9. Unusual Smells Coming from Vents or Furnace
Unusual odours during furnace operation should never be ignored they often signal an underlying issue.
Here’s what different smells can mean:
Burning dust: normal after a long off-season, but should disappear quickly
Musty or mouldy smell: possible mould growth in ductwork or the furnace itself
Rotten egg smell: potential natural gas leak — evacuate and call your utility provider immediately
Burning plastic or electrical odours: could mean overheating wires or failing components
If any smell lingers or returns, shut off the system and have it professionally inspected. Odours are often one of the earliest warning signs of more serious furnace problems.
10. Your Home Feels Dry, Dusty, or Uncomfortable
Older furnaces often struggle to maintain proper air quality and humidity levels, especially during BC’s dry winter months.
You might notice:
Dry skin, sore throats, or irritated sinuses
Dust buildup on furniture, vents, and electronics
Increased allergy or asthma symptoms from poor filtration
These symptoms suggest your furnace isn’t circulating or filtering air effectively.
Modern furnaces come equipped with advanced filtration options and humidity control features that help you breathe easier, stay healthier, and feel more comfortable throughout the heating season.
11. Weak Airflow from Your Vents
If the air coming from your vents feels faint or takes forever to warm a room your furnace may be struggling with weak air flow.
Common causes include:
Clogged air filters restricting airflow
Collapsed or disconnected ductwork
Failing or sluggish blower motor that can’t push air effectively
Weak airflow puts extra strain on your furnace, forcing it to run longer and work harder which shortens its lifespan and raises your energy bills. If you’ve ruled out filter and duct issues, poor airflow is a sign your furnace might be ready for replacement.
12. The Blower Fan Runs Constantly
If your furnace’s blower fan won’t shut off when it’s not heating something it is not working properly.
Potential causes include:
A stuck fan relay or faulty limit switch
Incorrect thermostat settings, like the fan set to “On” instead of “Auto”
A malfunctioning control board that fails to signal shutoff
Constant blower operation wastes energy, wears down the motor, and could be hiding deeper issues within the system. If resetting the thermostat doesn’t help, it’s time for a professional diagnosis and possibly a new furnace.
13. Water Leaks Around the Furnace
Water pooling near your furnace isn’t normal especially if it’s a high-efficiency condensing furnace.
Common causes of leaks include:
A clogged or cracked condensate line
Corroded internal components
A damaged heat exchanger leaking moisture internally
Moisture can lead to mould growth, rust, and even electrical damage, putting your home and furnace at risk. If you see water around your unit, shut it off and call a technician. Ignoring it can lead to bigger and costlier problems.
14. Your Carbon Monoxide Alarm Is Triggering
If your CO alarm activates while the furnace is running, treat it as an emergency. Carbon monoxide is colourless, odourless, and potentially deadly.
Possible causes include:
A cracked heat exchanger leaking combustion gases
A blocked flue or disconnected vent pipe
Backdrafting, where exhaust gases are pulled back into the home due to poor airflow or ventilation
Turn off your furnace immediately, ventilate the home, and call a licensed HVAC professional. Until the issue is diagnosed and resolved, do not use your heating system. Repeated CO alerts are a strong sign that furnace replacement is urgently needed.
15. Rust, Cracks, or Other Visible Damage
A visual inspection can reveal a lot about your furnace’s condition and its remaining lifespan.
Look for these warning signs:
Rust, corrosion, or soot buildup on the exterior or vent connections
Dents, cracks, or warped panels on the cabinet
Disconnected or sagging vent pipes
An overall dated design lacking modern safety features
Physical deterioration often means internal components are also worn or failing. If your furnace looks like it belongs in another decade, it’s time to replace it with a safer, more efficient model built for today’s standards.
Quick Checklist: Rule Out the Simple Fixes First
Before jumping to a full furnace replacement, check these basic items as they’re easy to overlook but might solve the issue:
Replace thermostat batteries
Reset any tripped circuit breakers
Clean or replace the furnace filter
Make sure vents and returns aren’t blocked by furniture or rugs
If your furnace still isn’t performing after these steps, and you’re noticing multiple signs from this list, it’s likely time to replace your furnace with a more reliable and energy-efficient option.
Why Choose A2B Plumbing and Heating?
We specialize in gas furnace installation, diagnostics, and HVAC repair or replacement for homeowners across Metro Vancouver and the Lower Mainland. Our licensed technicians offer honest advice, no-pressure quotes, and expert installations of energy-efficient heating systems designed for BC homes.
If you’re experiencing any of these signs, don’t wait until your system breaks down — take action now to replace your furnace before peak heating season hits. Call A2B Plumbing and Heating for a professional assessment — and discover how a modern, efficient furnace can save you money, boost comfort, and improve your indoor air quality.