How to rearrange an open hearth into closed one? Currently, there is a number of solutions available on the market – from the fireplace door or the fireplace insert to begin with, up to fireplace cassettes. Before taking final decision which option suits you most, it is worth considering such aspects as costs, the scope of work that will have to be carried out, as well as the heating capacity itself. We will look carefully into each of the available options – analysing the pros and cons so you can choose the best solution.
Closing the hearth with doors
Doors are relatively the simplest of all options in respect of costs as well as amount of work to be done. The doors will be about 3-4 times cheaper than, for example, fireplace cassette. And all you have to do is to fit them in place. There is no need to disassemble, dismantle or construct anything. Nice and easy – fast and cheap. Tailored-made, customised doors will fit perfectly to the existing hearth. However, when it comes to heating capacity, they do not stand the competition. The average efficiency of an open hearth closed with doors is around 20%. This is a really poor result. For comparison, the efficiency of an open fireplace ranges around 3-5% only. As in the case of the open hearth, the purchase costs are low, but the heating expenses remain high, so all in all the solution is far from being beneficial.
While fireplace inserts in new houses are a very good and simple solution, assembling them in an existing open hearth is much more labour-consuming. First and foremost, it requires serious renovation and construction work, which most of us prefer to avoid. You cannot simply fit in a fireplace insert without dismantling the existing construction. The scope of works will therefore include demolition of the existing hearth, and this already generates costs. The final amount depends largely on the renovation company engaged, the complexity of the reconstruction, as well as the type of building materials used – thus it is difficult to estimate the costs without knowing these details. Then you need to install the purchased fireplace insert (medium size insert is about PLN 4,000) and build the housing. The costs of housing the insert would range between PLN 3,000 – 5,000.
The above estimation shows that a minimum of PLN 10,000 would have to be paid for this kind of modernization. The scope of work would also be enormous. And how about efficiency? In this respect the fireplace insert differs significantly from the doors option. High-quality inserts are characterized by efficiency of even 85-90%. Such a result quickly shows in the costs incurred for the purchase of fuel (wood combustion is far more economical than in the case of doors) and in heating bills, especially if the fireplace is supposed to serve as a source of heat for the house, and not only as a decorative and representative element. Therefore, the money invested will probably pay off, although this requires a certain amount of time.
Fireplace cassette is a type of closed hearth that is assembled into the existing open hearth. Currently, the market offers a wide variety of fireplace cassettes, so you can choose an option that perfectly suits your needs and tastes. What is more, if the fire box of the existing hearth has a non-standard, atypical shape – including bevels or chamfers – you can order a cassette for a predetermined measurements. The purchase of medium-sized fireplace cassette made to measure, comparable to the insert analysed above, is about PLN 3,500. This is already a saving. When it comes to any sort of works, you don’t have to demolish or build anything. The very assembly is even simpler than in the case of doors. All you need to do is to insert the cassette into the existing hearth and seal everything with a glass cord. Importantly enough, the fireplace cassette doesn’t require to be connected directly to the chimney by any sort of venting pipe.
In terms of efficiency, cassettes reach an average of about 80%. As a consequence, the cost of the investment will pay off in a very short time, reducing significantly the fuel expenses and heating bills. Fireplace cassettes are equipped with a double steel coating (a double wall where the air that warms the house flows) and are lined with vermiculite. This very construction allows for such a high heating efficiency. The capable and effective convection tube system also plays an important role. Cold air is taken from the room through ducts located in the lower part of the hearth and heated, afterwards to be released back to the room through convection tubes (Fig. 2). A special ash pit and grate drawer allowing you to keep the hearth clean is also a huge advantage. What is more, the cassette increases the safety, as the construction prevents smoke from getting back into the room.
The above analysis clearly indicates the advantages and considerable competitiveness of the fireplace cassette as a way to close the open hearth over other options. The following table summary sorts out the information presented.
|The scope of work during assembly
|Low (about 20 percent)
|High (about 80-90 percent)
|High (about 80 percent)
|High (about 10k PLN)
|Middle (about 3k PLN)
|Only a few producers
When modernizing the open fireplace by changing it into a closed hearth, a fireplace cassette is definitely the best option. It allows to save time and money, and gives a far better heating efficiency than an open hearth or a hearth closed with doors.