Convert open fireplace to stove

Converting your open fireplace: same fire, 5 times the heat

An open fireplace is the biggest energy drain in the home: barely 10 to 15 percent of the heat stays inside, while the rest escapes through the chimney alongside your warm room air. By converting it into a closed insert stove, efficiency jumps to 75 to 85 percent, keeping the exact same cozy fire behind glass.

We complete full conversions in 2 to 3 working days: a custom insert fitted to your existing opening, a flexible stainless steel chimney liner, and complete finishing, all for a fixed price agreed upfront. Your fireplace stays in its familiar spot, but the heat finally stays in your room.

An open fireplace mostly heats the birds on the roof: an insert keeps that same beautiful fire, but delivers the heat to your side of the glass.

How the conversion process works

1. Step 1: measuring the fireplace and chimney

   We measure the width, height, and depth of the fireplace opening, inspect the existing flue, and determine which insert sizes will fit. If there is any doubt about the chimney structure, our camera inspection reveals the interior condition, with the cost deducted if you proceed with the conversion. Feel free to measure the opening dimensions yourself in advance to give us a head start.

2. Step 2: selecting the right insert and heat output

   The insert must fit both the wall opening and the room size: excessive output turns your living room into a sauna, while too little forces the appliance to run constantly at maximum. We calculate the required heat output based on surface area and insulation levels, using a rule of thumb of 1 kilowatt per 8 to 10 square meters. You then choose from 2 or 3 matching models, each clearly detailed with its power output and glass size.

3. Step 3: installing the chimney liner and connecting the insert

   A flexible stainless steel liner, sized specifically for the insert, is pulled through the existing flue and connected gas-tight. We seal the old, oversized fireplace cavity neatly with fire-rated boards and insulation, incorporating convection vents to circulate heat into the room. You keep the view of the flames, while heat loss becomes a thing of the past.

4. Step 4: finishing, test burn, and certification

   We finish the surround paint-ready, guide you through the first burn with clear instructions, and provide the compliance certificate for your documentation. Your fire burns that very evening, but with heat that stays inside, and your first annual chimney sweep is scheduled right away.

How much does converting an open fireplace cost?

The insert unit itself costs 1,500 to 4,000 euros, flue lining costs between 900 and 1,800 euros installed, and structural conversion including sealing and plaster finishing ranges from 600 to 1,500 euros. All together, a complete fireplace conversion usually lands between 3,000 and 6,500 euros, including 6 percent VAT for homes older than 10 years. For detailed lining prices, check our guide on stainless steel flue lining.

Your return on investment

Do the math: burning 6 cubic meters of wood a year in an open fireplace only yields the actual warmth of barely 1 cubic meter. A modern insert meets that exact same heating demand using just 1.5 to 2 cubic meters, saving you up to 4 cubic meters of firewood every single year.

At current firewood prices, the entire conversion pays for itself in 5 to 8 years, and your daily comfort improves from day one: no more cold drafts pulled toward the hearth, just steady heat lingering in your home.

Why a chimney liner is a requirement, not an option

An open fire relies on a large, cold masonry chimney. An insert sends much smaller volumes of much hotter flue gases through that same channel. Without a lining, these hot gases condense against cold brickwork, causing creosote build-up, unpleasant odors, and serious chimney fire risks. A custom flexible stainless steel liner solves this permanently, installed via our chimney lining service within a single day, backed by a 10-year system warranty.

Leaving it open and burning better: why it does not work

The strong draft of an open fireplace pulls hundreds of cubic meters of heated room air up the chimney every hour, even when using the dryest wood and best techniques. Trying to burn better in an open fire slightly reduces losses, but never yields real efficiency. You can read general burning guidelines via the official government heating advice, but true energy savings only come with the sealed glass door of an insert.

Can every open fireplace be converted?

Virtually all of them: the main deciding factors are the width and height of the opening, along with the structural state of the chimney flue. Inserts come in dozens of dimensions and depths, ranging from compact 60-centimeter models to widescreen units over 80 centimeters wide, with custom frames easily covering minor sizing gaps.

Options for pellet inserts or full new hearth installations

If you prefer switching to wood pellets, we can install a pellet insert into the same opening via our inset pellet stove installation service. If you want a larger, higher, or completely relocated fireplace on a different wall, our built-in fireplace service can design a brand-new false wall alcove from scratch. We can provide quotes for these alternative options alongside a standard conversion upon request.

Maintenance after conversion

Your new insert and liner require the exact same annual care as any stove: a chimney sweep costing between 60 and 90 euros plus a basic appliance check, ideally carried out together. Learn all about recommended intervals in our maintenance guide, and we will schedule your first checkup one year out upon handover.