Indoor climate and energy efficiency of apartment and educational buildings in Estonia

The years 1960-1990 saw an extensive construction of apartment buildings in Estonia. In 1970s the specific heat consumption of apartment buildings made up about 350 kWh/m2 per year. The 1990s saw the beginning of the renovation of heat substations, heating and ventilation systems and building envelopes. The renovation of windows in old apartment buildings was accompanied by problems in the indoor climate. The problem of indoor climate seriously concerns schoolhouses without mechanical ventilation and partly renovated old apartment buildings. Characterised is the influence of the new domestic hot water (DHW) calculation method on the determination on the equipment of heat substations and district heating network. The increase of energy efficiency of buildings by heat recovery of heat of exhaust air by heat pump is analyzed. In old apartment buildings one of the possible solutions is the air change arrangement by room heat recovery units and programmable exhaust ventilators in toilets, bathrooms and kitchens.