Written on: 07/01/2011
I bought a Viessman Vitodens 100 Compact in September 2008 and it has been entirely satisfactory. I understand the early ones were not so good, and the newer ones are even better. It is essential to have it installed by a Viessmann-approved person, trained by them (free). There is a list on their website. That way you get the 5-year parts and labour guarantee. If you are putting it on an old heating system, you are very likely to have a lot of dirt, rust, sludge and sediment in it, and it is essential to have it thoroughly cleaned before the new boiler is fitted. This alone took two men more than half a day in my house. You should also consider having a Magnaclean or Spirovent fitted, these are devices which trap residual dirt out of the water and prevent it causing blockages or wear. Avoid a cheap quote where the installer has to cut corners to make a profit.
I chose the 100 Compact (heat-only boiler)with a hot-water cylinder rather than a Combi, because it is extremely simple and has very few parts to go wrong. Combis are generally not as reliable, whatever the maker. It has a stainless steel heat exchanger which will not corrode and has a 10-year guarantee. It is also very small and quiet.
Mine has never gone wrong, which is what I would expect from a premium German product.
It has been much more economical than my old iron Potterton boiler. In summer it uses half a metre of gas a day, the old one used 1.1 metres. In a very cold year it uses 1300 metres of gas; the old boiler used 1800 metres.
As rated by real users