After the oil crisis in the 1970’s the Swedish government encourage households to convert oil based heating systems to electrical heating, for example by offering subsidies. In 2006 more than 700 000 single-family houses used pure electrical heating systems, including heat pumps. That constitutes more than 40 percent of the total Swedish detached houses [3]. Including combined heating systems the number is even higher. In 2006 subsidies for converting direct electrical heating as well as oil based heating systems to district heating, biomass or heat pumps were re-introduced. The subsidy for oil based systems ended in 2007, while the one for direct electrical heating will be available until 2010. Prior to those, there were conversion subsidies from 1997 to 1999 and 2001 to 2003 [4]. The fluctuating allowance system has caused an unpredictable market for heating systems.

Heat pumps have gained significantly increasing market shares since the middle of the 1990’s. Half of the European heat pumps are installed in Sweden [5] and in 2005 the total official number of installed heat pumps reached 600 000 [6]. Air-to-air heat pumps are however not included in these figures since the statistics are kept secret due to competition, but they are simple solutions with low investment costs, frequently used mainly in electrically heated buildings without water-based central heating systems. The market introduction of heat pumps in Sweden is considered a success, although this trade has also suffered from the unstable market the last years.

The use of wood pellet in the residential sector has increased more than seven times in the period 2000 to 2005, according to the pellet industry [7]. So far, burners have mainly been installed in existing (oil) boilers, but at present there is a trend towards boilers and systems adjusted to pellet. The total number of installed pellet boilers in detached houses was more than 80 000 in 2005 [8], which has increased further since then. During 2007 the number of sold pellet units, however, decreased by 80 percent compared to the previous year. Several companies had to reduce their staff, some were bought by larger companies and some even went bankrupt.

The solar heating trade in Sweden is small. There used to be 10-15 different companies, but over the last years numerous new companies were founded, mainly focusing on import and often vacuum tube collectors, and several large well-established suppliers of heating systems started to promote solar collectors as well. A total of 350 000 m2 glazed solar collectors are installed, from which about 30 000 m2 were installed in 2006 [9]. Since 2000 there is a subsidy for installation of solar heating

systems, which will end in the end of 2010. This can be applied for separately from the conversion subsidy. There is no statistics available on sold combined solar and pellet systems.