Retrofitting Electrically Heated Single-Family Houses to Net-Zero Energy
Abstract
Only in Sweden, single-family houses account for approximately 30% of energy use in all buildings and a large part uses only electricity for heating. The potential for improvements on energy efficiency in these houses is large. This study theoretically investigates retrofitting of electrically heated Swedish single-family houses by using an air-source heat pump for both space heating and domestic hot water. Combination with solar collectors and solar cells were also theoretically investigated. Since this solution is an add-on to the existing heating system the investment cost can be reduced compared with a new heat pump installation for domestic hot water. The total annual energy reduction for domestic hot water and space heating in a Swedish single-family house when using the combined heat pump and solar thermal collectors was estimated to be roughly 70%. The remaining electricity demand for electric appliances can be covered by approximately 10 kWp solar cells therefore reaching net-zero energy level.
Keywords
Retrofit, Net-zero energy houses, Solar thermal, Heat pump, Single-family houses.