How to Know When to Replace a Fireplace Insert: 5 Signs You Shouldn’t Ignore

Your fireplace insert should add warmth and comfort to your home, not create odd smells, spike your energy bill, or pose a safety risk.

No matter the type, gas, electric, or wood-burning, all fireplace inserts have a lifespan. And knowing when to replace a fireplace insert can help you avoid bigger problems (and bigger costs) down the line.

Here are five signs it might be time for an upgrade and what you can do about it.

1. It’s Not Heating Like It Used To

Your insert is running, but is your room still cold? If it feels like you’re getting less heat than you used to, or if you’re relying more on your furnace to stay warm, something’s not right.

Signs of declining performance: 

• Takes longer to warm the space
• Heat doesn’t spread beyond a few feet
• Still relying on your furnace to stay comfortable

Older inserts often lose efficiency, causing your energy bills to rise while comfort drops. Installing a new fireplace insert can deliver more reliable and efficient heat, consuming less energy, making it a wise investment for the future.

2. You See Rust, Cracks, or Warping

A little wear and tear is normal over the years, but if your insert is starting to show visible signs of damage (especially on critical parts) it’s time to take it seriously.

Watch for:

• Cracked fireboxes or doors
• Rust forming inside or outside the unit
• Warped frames or loose-fitting components

Cracks can allow smoke or heat to escape into your living space, and rust can weaken structural integrity. In gas models, damage could even lead to carbon monoxide leaks. If your unit looks damaged, then it’s time to move on.

3. It Smells Strange 

There’s a difference between “woodsy fire vibes” and “something smells wrong.”

Smells to be cautious of: 

• Strong chemical or metallic odors
• Lingering smoke (especially with gas inserts)
• Musty or burnt smells even when the unit is off

Unusual smells can indicate everything from poor combustion to ventilation problems, or even a gas leak. That’s not something to ignore. If the smell doesn’t go away with a simple cleaning or inspection, it’s time to replace.

4. It’s Getting Harder to Start or Control

If your insert is malfunctioning, fails to ignite, turns off unexpectedly, or simply isn't functioning properly, it indicates that the internal parts are beginning to deteriorate.

Common issues:

• Constantly relighting your gas insert
• Remote or buttons not responding (for electric units)
• Wood insert struggling to keep a flame going

Sure, you could keep calling for small repairs. But if it’s happening often, those service visits add up, and your insert still isn’t reliable. Replacing the unit often costs less in the long run, and gives you modern features like remote control, auto-timers, and higher efficiency.

5. It’s Just Old

Most inserts last 10–20 years, depending on type and maintenance. If yours is approaching (or past) that mark, it’s time to start thinking ahead, even if it technically still works.

Signs of aging:

• It was already installed when you bought the home… and that was years ago
• It looks dated or doesn’t match your style anymore
• Parts are hard to find or no longer made

Newer inserts are quieter, cleaner-burning, and way more efficient than their early-2000s counterparts. And let’s be honest, replacing it can completely transform the look of your space. It’s a functional upgrade and a design glow-up.