• Energy Research

The economic viability and investment cost of the energy retrofit of apartment buildings are analysed through different energy efficiency levels. To analyse retrofit policy cost-optimal energy efficiency levels and investment costs, a baseline of measured actual energy usage of apartment buildings was created and then individual energy-saving measures and retrofit packages were composed. The cost-optimal level over a 20-year period for apartment building retrofit was a low-energy-building energy performance level, with an investment cost of €150–170/m2. Retrofit to low energy building level would be economically viable but the investment capability of apartment owner associations is found to be insufficient for the necessary investments to achieve low-energy-building energy performance. Therefore, it is necessary to determine what levels of financial support can encourage retrofit to occur. The analysis of the current retrofit shows that subsides will increase investment by apartment owner associations in...

AbstractAccording to an assessment protocol developed as a part of the INSULAtE project, indoor air quality measurements were conducted in three Finnish and Lithuanian multifamily buildings before and after energy retrofits. Additional cases from Estonia included one retrofitted and two non-retrofitted buildings. Measured gaseous pollutants included carbon dioxide (CO2), volatile organic compounds (VOCs), formaldehyde (CH2O), and nitrogen dioxide (NO2). Low CO2 concentrations in Finland could be attributed to common use of mechanical exhaust ventilation. WHO guidelines for CH2O were not exceeded in any of the measured apartments. No statistically significant changes were seen in VOC or NO2 after retrofits.

Renovation of old apartment buildings is a topic of current research interest throughout the Eastern Europe region where similar typology is derived from the period of 1960–1990. Thermal bridges, essential components of the transmission heat loss of a building, have to be properly evaluated in the energy audit during current state-of-the-art situation as well as in the comparison of renovation solutions. Resulting from field measurements and calculations, we propose linear thermal transmittances Ψ of thermal bridges for four types of apartment buildings: prefabricated concrete large panel element, brick, wood (log), and autoclaved aerated concrete. Our results show that thermal bridges contribute 23% of the total transmission heat loss of a building envelope before renovation. After renovation thermal bridges ac­count for only 10% if windows are repositioned into additional external thermal insulation and balconies are rebuilt as best practice. Inversely, impact of the thermal bridges might be up to 34%, depending on the wall insulation thickness. We have also found that the relative percentage of thermal bridges after renovation increases and the negative impact of the thermal bridges of certain junctions cannot be compensated with thicker wall insulation. Results obtained in this paper are useful for energy audits.

AbstractThe paper discusses energy renovation scenarios from major renovation to nZEB level for apartment buildings in Estonia (cold climate). The study analyses energy usage and economic viability taking into account a possible increase in the lease income after renovation under apartment building renovation scenarios. Our results show that deep renovation of old apartment buildings enables the energy performance requirements of nearly zero energy apartment buildings to be achieved. With nZEB renovation, reductions are ca 70% in delivered energy (heating energy + electricity) need and ca 60% in primary energy need. Payback period of nZEB renovation without increased lease income is around 30 years. In the best scenario case, the payback period of nZEB renovation is around eight years when the increase of the annual lease income is taken into account.

H2020 project DRIVE0 (Driving decarbonisation of the EU building stock by enhancing a consumer centred and locally based circular renovation process) aims to come to a decarbonisation of the EU building stock and to accelerate deep renovation processes by enhancing a consumer centred circular renovation process in order to make deep renovation more attractive for consumers and investors, more environmental friendly. Circular renovation concepts and process will specifically be developed and implemented in the seven demonstration cases in seven countries, representing all climatic zones in Europe

AbstractIn Estonia there is a total of approximately 27,000 apartment buildings, and approximately 90% of all apartment buildings were built before 1990. The majority of those buildings have same typical problems: high energy consumption levels, insufficient ventilation, uneven indoor temperatures, and insufficient thermal comfort levels. Therefore, a pretty extensive, or ‘deep’ level of renovation is required. Any large-scale and systematic renovation process for apartment buildings in Estonia is complicated due to the fact that a total of 82% of dwellings are privately owned. Apartment buildings are generally managed by apartment associations which means that all of the apartment owners in each building must agree on the volume of any renovation work and also on the budget for such work.During the period between 2010-2014, a total of 663 apartment buildings have undergone renovation work in Estonia thanks to a support scheme that is joint-financed by Assigned Amount Unit trading and a government budget, administered by Fund KredEx. The total of investment in relation to apartment associations and the grant scheme amounted to 151 million euros, of which 38 million took the form of grants. Average energy savings per apartment building were 43% and the total annual energy saving was approximately 60GWh. The main lessons learned have been that preparation with an apartment association in regard to renovation work takes time - up to two years - and there is no direct way in which apartment associations can be guided when it comes to renovation work; this can only be managed through raising awareness and though good example.A total of 102 million euros of European Union Structural Funds will be used in a new grant scheme which started in 2015, to renovate existing apartment buildings in Estonia. This paper describes the new grant scheme and measures to avoid and overcome the main problems which occurred in previous grant schemes.

Abstract EPBD directive 2002 and its recast 2010 have led to significant efforts in Member States to improve the energy performance of buildings. Important aspect of this goal is the compliance of building energy performance assessment which needs developed procedures in order to be able to achieve stringent energy targets in practice. Transmission characteristics have a significant role in energy efficient buildings. QUALICHeCK project conducted a review of thermal bridges in energy calculation and compliance procedures in nine European countries (Austria, Belgium, Cyprus, Estonia, France, Greece, Romania, Spain, Sweden). Results showed that there are four main types of methods to take thermal bridges into account in transmission heat loss calculation: the detailed calculation based on linear thermal transmittance values, simple basic rules, default transmittance values, and mean U-values. Regarding the compliance, review showed that often there are no specific thermal bridge related compliance procedures. General conclusion of this study was that compliance frameworks needs to be extended in order to be able to assess as built energy performance. It is common approach in many countries that control mechanisms stop with building permit phase.