An open fireplace has charm - the crackling, the warm light, the special atmosphere. At the same time, you may also know the other side: a lot of heat is lost unused, wood consumption is high and the room doesn't get really warm despite the fire. This is exactly where a fireplace cassette comes in. It makes your open fireplace more efficient, safer and more suitable for everyday use. And best of all, it preserves the original character of your fireplace.
In this article, you will find out when it is worth retrofitting a fireplace cassette, what costs you will incur and what the process looks like from the initial consultation to the finished installation.
What you can expect
- Why should you retrofit a fireplace cassette?
- How can I retrofit a fireplace cassette in my open fireplace?
- How much does it cost to retrofit a fireplace cassette?
Why should you retrofit a fireplace cassette?
More heat and less wood consumption
In an open fireplace, a large proportion of the heat escapes directly via the chimney - often only 10 to 30 % of the energy generated actually remains in the room. A fireplace cassette closes the combustion chamber and optimizes the air flow. This increases the efficiency to at least 75 %.
This means that significantly more heat stays where you want it: in your living space. You use less wood, have more heat output and benefit from combustion that works as efficiently as a modern fireplace insert. At the same time, you can continue to enjoy the original charm of your fireplace.
More safety
An open fireplace is beautiful - but flying sparks and open fires require your constant attention. With a fireplace cassette, you can regain a feeling of security. It protects what means the most to you: your family, your pets, your home, your peace of mind. For many, it is precisely this protection that is a decisive argument for a safe fireplace.
Fireplace cassettes for more safety in your home
Retrofit a heating cassette and use an open fireplace without restrictions
You may be wondering whether you can still use your open fireplace at all.
Basically yes - but only to a very limited extent. According to the law, open fires may only be used occasionally: a maximum of 8 days a month, for up to 5 hours at a time.
This changes with a fireplace cassette: it is considered a closed fireplace, which means you can use your fireplace regularly and without restrictions. All fireplace cassettes from Spartherm meet the legal requirements.
How can I retrofit a fireplace cassette into my open fireplace?
A fireplace cassette can be easily integrated into most open fireplaces - quickly, cleanly and without major conversions.
The prerequisites are
- a suitable chimney and
- suitable installation dimensions
But don't worry: even unusual chimney shapes are no obstacle. Custom-made products enable installation to the millimetre and individual production.
FIND OUT MORE ABOUT CUSTOM-MADE PRODUCTS
Step 1: Involve your specialist dealer early for the best result
Questions quickly arise, especially when retrofitting: Which size fits? Which technology makes sense? What do I need to pay attention to? A specialist dealer will relieve you of these uncertainties and ensure that your fireplace cassette fits securely, works efficiently and gives you many years of pleasure.
You can use the Spartherm dealer search to quickly find a contact near you.
FIND A SPECIALIST DEALER NEAR ME
Step 2: On-site check
The specialist dealer measures your fireplace, checks the chimney and shows you suitable models - whether standard or custom-made. This way, you know early on which solution really suits you and your home.
Step 3: Selection & installation
The fireplace cassette is not simply inserted. It is precisely inserted, securely connected and cleanly sealed by trained personnel. Installation usually only takes a few hours - you can then use your fireplace again straight away.

How much does it cost to retrofit a fireplace cassette?
Retrofitting an open fireplace - costs at a glance
The cost of retrofitting a fireplace cassette is usually between 2,000 and 5,000 euros.
Factors that influence the costs
- Size and shape of the fireplace
- Model and equipment
- Installation effort
- Any adjustments to the existing appliance
If you want to know exactly what retrofitting your fireplace will cost, it's best to speak to a specialist dealer in your area.
Your fireplace cassette could look like this
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Be inspired by different designs and discover how beautiful and modern a retrofitted fireplace can look. |
Get your open fireplace ready for the future
Retrofitting a fireplace cassette is one of the easiest and most sensible ways to upgrade your open fireplace: more warmth, more safety, more comfort - and without any major modifications.
With a specialist dealer at your side, you'll quickly find the solution that's perfect for your home.
Get non-binding advice and start your new fireplace experience.
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