Built-in pellet stove installation

Built-in pellet stove installation: from open fireplace to 85% efficiency

A built-in pellet stove, also known as a pellet stove cassette or pellet insert, is installed directly into an existing open fireplace, mantelpiece or custom-designed alcove. This upgrades your heating efficiency from less than 15% with a traditional open fire to over 85% with a modern built-in pellet stove. This is not just a minor improvement; it is a fundamentally different way to heat your home.

You still get to enjoy the cozy atmosphere of a real wood fire, but with the added benefits of automatic controls, thermostat regulation and drastically lower energy consumption. Your current mantelpiece remains completely intact. The pellet stove cassette fits perfectly into the recess, leaving only the beautiful flames and the control panel visible.

"The most popular conversion we do is upgrading an open fireplace to a built-in pellet stove. Our customers are always amazed by the difference, not only in terms of heat output but also the convenience of automatic operation and the complete absence of smoke and dust in their living room."

How do we install a built-in pellet stove?

The installation of a built-in pellet stove is more complex than fitting a freestanding model. It is custom work that requires deep expertise in both pellet stoves and fireplace constructions. At Pelletkachelzorg, we tackle this process step by step:

1. Step 1: free site visit and measurements

   We provide a free home visit to accurately measure the dimensions of your open fireplace or alcove. Not every fireplace opening is immediately suitable for a pellet stove cassette, as the width, height and depth must be exactly right. We also inspect the condition of the chimney and determine if the existing flue can be reused.

2. Step 2: adapting the flue

   Existing chimneys for open fires are usually 200 to 300 mm wide. This is far too wide for a built-in pellet stove, which requires an 80 or 100 mm flue. We slide a stainless steel flue (flexible or rigid) of the correct diameter down the existing shaft. This technique preserves the structure of your chimney while ensuring the flue system meets the Belgian NBN standards for smoke extraction.

3. Step 3: installing the cassette and providing ventilation

   The built-in pellet stove is carefully slid into the recess and positioned correctly. There must be ventilation openings around the cassette, typically at the top, bottom and sometimes the sides. The stove transfers heat to the air flowing along its casing. If this air circulation is blocked, the overheating protection system will trigger.

4. Step 4: external air supply

   In well-insulated and airtight homes (new builds or recently renovated houses with new windows), we install an external air supply. This is a pipe running from the outside directly to the stove to provide fresh combustion air. Without an external air supply, negative pressure can build up inside the room, leading to poor draft and incomplete combustion.

5. Step 5: finishing, start-up and instructions

   Where necessary, the alcove is finished with fire-resistant materials. We connect the pellet stove to the power supply (using a grounded socket), start the appliance and adjust the combustion parameters specifically for your room. Finally, we provide a comprehensive explanation on how to operate the stove and perform daily maintenance.

Installing a built-in pellet stove in an existing fireplace

This is the most requested scenario and our true specialty. You currently have an open fireplace that barely produces any heat, blows smoke and dust into the room and wastes massive amounts of energy. A pellet insert solves all these problems at once.

However, not every open fireplace is automatically suitable for a built-in pellet stove. The requirements are:

• Minimum width: 55-60 cm for most pellet stove cassettes

• Minimum height: 50-55 cm (depending on the brand)

• Flue: needs to be adapted, as existing chimneys are usually too wide

• Ventilation: sufficient space around the cassette to ensure proper air circulation

• Mantelpiece: must be heat-resistant or adequately protected

Are you unsure if your open fireplace is suitable? We will assess it for free during a home visit. You can find more background information in our blog post about installing an insert in an existing fireplace.

Built-in pellet stove without an existing chimney

Do you lack an open fireplace or chimney but still want a built-in pellet stove? That is definitely possible, though it is more complex and expensive. A custom alcove has to be built (using masonry or drywall) and a completely new twin-wall flue system must be installed.

The total installation costs can then amount to €2.000 to €3.500, excluding the stove itself. In some cases, a freestanding pellet stove becomes the more pragmatic choice. We will give you honest advice on which option makes the most sense for your home. You can read more about this in our article built-in stoves without a chimney: is it possible?

Cost of a built-in pellet stove installation

The costs for a built-in pellet stove installation consist of the stove itself and the labor required for fitting:

At Pelletkachelzorg, you will always receive a detailed quote after the free site visit. All costs are clearly broken down, covering the stove, the flue system, labor and any potential extras. No surprises and no guesswork. For a complete overview of the costs, check out our article on built-in pellet stove prices.

Built-in vs. freestanding: which one should you choose?

Are you torn between a built-in pellet stove and a freestanding model? The best choice depends heavily on your specific situation:

1. Choose built-in if you already have an open fireplace, want to save floor space or highly value a sleek, integrated design.

2. Choose freestanding if you do not have an existing fireplace, want the stove to be a standout design piece in the room or prefer a simpler installation process.

You can read an extensive point-by-point comparison in our blog post built-in vs. freestanding.

Which brands do we install?

Pelletkachelzorg installs built-in pellet stoves and cassettes from all major reputable brands:

• MCZ - sleek design, quiet operation, featuring the popular Vivo 80 series

• Piazzetta - premium build quality, versatile IP 68/58 models

• Ravelli - excellent value for money, robust RC series

• Edilkamin - wide product range, including the popular Pellbox cassette

• Extraflame (La Nordica) - compact and highly affordable built-in models

• Eva Calor, Haas+Sohn, Rika and many more

For a fair and detailed comparison of this year's top models, read our article highlighting the best built-in pellet stoves of 2026.

Maintenance after installation

A built-in pellet stove requires the exact same maintenance as a freestanding model. This means emptying the burn pot every 2-3 days, clearing the ash pan weekly and booking an annual professional service that includes sweeping the chimney and issuing a cleaning certificate.

An extra point of attention for built-in models is that the ventilation openings around the cassette must remain completely free of dust and obstacles. Be sure to check them on a monthly basis. If you experience a malfunction or defect, we will of course come directly to your home to repair your built-in stove.

Built-in pellet stove installation in Limburg and Flemish Brabant