Pellet Inserts for Existing Fireplaces: Which One Is Right for You?

Pellet Inserts for Existing Fireplaces: Which One Is Right for You?

Why Convert an Open Fireplace to a Closed System?

That classic open fireplace has served its time. While it was once the heart of the home, today's open hearths are recognized as significant contributors to fine particulate pollution — and in many regions, regulations are tightening or banning their use altogether.

If you're planning a home renovation and have an old open hearth, the smart move is to close it off and upgrade it. Treating it purely as a decorative element — and using it only occasionally — may still be an option, but environmental standards in many areas strongly favor the conversion to a closed, pellet-fueled system.

Beyond compliance, closing off your fireplace simply makes your home more energy-efficient, warmer, and more comfortable throughout winter. Why settle for heat that escapes straight up the chimney?

Open-Hearth vs Enclosed Fireplaces: Heat vs Aesthetics (2025 Guide) — Pure Flame Co

How to Install a Pellet Fireplace Insert

A pellet insert is purpose-built for faster and more straightforward installation compared to a traditional closed fireplace. The insert dimensions are designed to fit neatly within existing hearth openings, and the flue connects directly to your existing chimney via a flue adapter — no major structural changes required.

Here's a typical installation process:

  1. Transporting the insert to the installation location
  2. Positioning and placing the insert into the existing hearth opening
  3. Connecting and fitting the flue adapter to the chimney
  4. Initial start-up, calibration, and test ignition
  5. Finishing the surround with a drywall filler or custom trim panel

Before you begin: Have a qualified technician assess the power output you need to heat your space adequately. Don't guess — an undersized unit will struggle all winter.

If your fireplace hasn't been used in a while, always have the chimney professionally inspected. Obstructions and buildup can create serious safety hazards.

What to Look for in a Quality Pellet Insert

Not all pellet inserts are created equal. When evaluating models, keep these key criteria in mind:

⭐
4–5 Star Environmental Rating
High efficiency with low emissions means you can run your insert even on high-pollution alert days.
💰
Tax Incentive Eligibility
Look for models that qualify for energy efficiency rebates or eco-bonus deductions in your area.
🔇
Quiet Operation
A quality insert should fade into the background — you should hear the warmth, not the machine.
🪵
Clean, Minimal Design
The best inserts complement your living space. Look for sleek faces that blend with modern or traditional interiors.

Standard air inserts come in varying widths — typically 60 cm and 70 cm — so always measure your hearth opening carefully before purchasing. Choosing the right fit makes a significant difference both aesthetically and in heat output efficiency.

Thermo Inserts: Heat Your Entire Home

Want to go beyond heating a single room? A thermo insert — also called a hydro pellet fireplace insert — connects to your home's existing radiator network, effectively turning your fireplace into a boiler substitute for the whole house.

The installation is more involved than a standard insert (masonry work is typically required), but the payoff is substantial. With one appliance, you can heat every radiator in your home and significantly reduce your heating bills during the coldest months of the year.

  • Heat every room via your existing radiator system
  • Dramatically cut winter heating costs compared to gas boilers
  • "Rest" your boiler system mid-season for extended savings
  • Available in multiple output configurations (e.g. 18 kW and 24 kW)


Ductable Pellet Inserts: Room-to-Room Warmth

Ductable inserts use an internal fan system and wall pipes to distribute warm air from the fireplace insert into other rooms throughout your home. Installation requires a bit more planning than a standard air insert, but the versatility is hard to beat.

If your home layout allows for ducting, the additional installation effort pays off handsomely. Heat savings across the whole home are considerably more substantial than a single-room unit — and you won't need separate heating sources in every room.


Pro Tip: Ductable inserts pair particularly well with open floor plans or two-story homes where warm air naturally rises. A ducting plan drawn up before installation will help you maximize coverage and efficiency.

 

Featured Product

ComfortBilt HP22i Pellet Stove Fireplace Insert

A top-rated insert designed for straightforward installation into existing fireplaces — efficient, quiet, and built to last through every cold season.

HP22i Pellet Insert

Always consult a qualified heating professional before purchasing an insert. Output requirements vary by home size, insulation quality, and regional climate.

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