Wanted to share some information on pönttöuuni (metalcontainer wood burning stove) used for generations in Finland to efficiently heat house with wood fuel. This type of stove was very popular in the 1850 - 1970, then a bit replaced by more convenient heating systems, but during recent 10 years it has started to gain popularity as the price of electricity has skyrocketed and now there are several manufacturers in Finland offering many models of pönttöuuni commercially.
Basic idea of the pönttöuuni is exactly like rocket mass stove heater, it has very tall construction, primary burning chamber constructed of ceramic fire resistant bricks, secondary return of the fire gases heat the external brick cover before the smoke enters chimney from the bottom of the pönttöuuni.
Markku Salmela : Yes much like a Rocket Stove ! I have made a link to another 'Pontto', this one has a pull-chain Connected to a Lever high up on the
righthand side, I THINK this is a lever for a bypass to warm the chimney, before it is reverted through all the baffles inside !
Is that your impression too? Heres the link to the picture ::::-->
http//www.kinanen.fi/wordpress/?p=310 Highlite the Bold part and right click to open in the Address Window, or as a Google Search !
For the good of the cause, BIG AL
Success has a Thousand Fathers , Failure is an Orphan
It looks like chimney valve, which is open when fire is burning and to be closed when fire is our, to keep the heat in the stove. Some old pönttöuuni has two valves, lower is chimney valve and upper is for ventilation, and typically in that case there is rotating baffle in the top front of the pönttöuuni. It was also called as "tobakko smoking valve", basically you could by opening the top valve to vent room air into chimney, and still keep the lower chimney valve closed not to loose the heat from the stove. Nowadays those "tobacco smoking valves" are not legal in the new stoves, as combining smoke and room air to single chimney is considered fire hazard in case of chimney fire.
Originally pönttöuuni was merely meant for heating during the cold months, and there was no need to burn wood in the summertime, therefore originally the pönttöuuni was always storing as much of the heat as possible.
In modern times when some fireplaces are meant for creating nice ambience and not so much of a heating there are these bypass valves to get rid of most of the heat, this is a recent "fashion" and it has not been used in the original pönttöuuni.
I know some to recommend, but they should be asked for the specifics concerning the models, and pricing for the installation on site. Pönttöuuni is shipped in parts form and basically build on site with mortar.
Maybe you could start by asking from these their most popular and recommended pönttöuuni models and they may also send pictures from their reference sites;
The copper coloured one looks very nice I can see it being a good product here in France if the price is right .
I have not been able to find any tech read out like how many watts how long they stay warm etc etc .
Living in Anjou , France,
For the many not for the few
Some key points translated;
- 11,1kg wood produces 41kWh net-heat
- efficiency 86% (exceeding the CE requirement by 23%)
- graph shows temperature gradient in between the air and outside of the pönttöuuni
- cooling period of highest temperature to 50% was 8,4h exceeding CE requirement by more than 100%
- after 20h temperature gradient was more than 25% of the highest value
Called to the manufacturer first on the list today and they confirmed being able to ship to France, if you feel like it, they are happy to discuss the details over the phone with you. Asked more about the copper colored one, he sais ite paint which looks a bit like antique hammered copper, and stressed that the metal cover material is still galvanized steel and not copper. The price for 68cm diameter 200cm tall antique copper colored is currently 3200€ fully assembled (in Finland).