Abstract
The residential sector contributes largely to the energy consumption in Europe: around 40% of the EU energy use (RHC-ETP, 2011). For a massive reduction of the energy consumption in the European residential sector, a common practice is the retrofitting of existing buildings. In this context, multifamily houses (MFHs) are considered to be easier retrofitted, partly because their exteriors are more uniform than single-family houses’ - which makes external insulation and glazing replacement easier to install - and partly because each building contains multiple dwellings - therefore a single action can affect more living area. The purpose of this paper is to report on the design phase of a multifamily house located in Madrid, Spain. The refurbishment concerns the installation of both passive and active solutions. In particular, transmissions through the envelope are reduced by the addition of an insulation layer and new windows. DHW production, space heating and cooling are guaranteed by an air-to-water heat pump. Heating demand and Domestic Hot Water (DHW) production are also partially covered by solar thermal panels installed on the parapet of the building. The impact of the retrofitting measures on the energy consumption have been assessed starting from energy audit data, going through modelling and simulating the building’s envelope before and after the retrofit , and finally analysing the building and energy plant together. The simulation work shows a set of integrated measures suitable to achieve a primary energy consumption for heating, cooling and domestic hot water, lower than 50 kWh/m²y.