A residential house owner decided to install solar thermal technology re-using his tank and supplying the house with advanced collectors. The solar collectors now produce 60% more energy than is required according to the industry test institute SP.

The sun produces 5 500 kWh per year with a reduction of the total energy costs by 21%. Based on the current price of energy the pay-back period is 4 ½ years or using the annuity model 38 öre/kWh or 3 cents/kWh during the next 20 years.