Use of energy-signature method to estimate energy performance in single-family buildings

Abstract: The renewal of the existing housing stock is a slow progress and the existing is quite old. The existing housing stock represents a large amount of the bought energy need for heating and a simple method for quickly determining the energy performance is needed. There are many different methods for estimating the energy performance of buildings. In this report the feasibility of using a single-variate steady state method to investigate energy performance has been tested. Bought energy need in single-family houses in a cold climate has been observed during the cold period. The observations have been made with the help of a measurement system requiring a minimal installation. The heat loss factor of the observed buildings has been determined using the energy signature approach and different time scales have been tried. The result shows that to determine the heat loss factor of single-family buildings, a single-variate method is valid. Daily averages are a good time scale for houses using radiators under the windows to heat the building. Buildings with floor heating in concrete slab need to have a longer time scale, around 3 days. The method does not account for occupancy levels and separate energy use in specific installations is not easy to estimate with the minimalized measurement setup. A combination of heat sources such as district heating, electrical heating, heat recovery and/or fire stove is problematic to handle with the energy signature method if enough observations for al heat sources can be achieved.