Green homes, for a 120m2 apartment the cost is 48 thousand euros, for the villa you need up to 86 thousand

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It won’t be at zero cost, on the contrary. The adaptation of Italian buildings to the European directive on green homes will be anything but painless. This is clearly stated in the report “The energy redevelopment of the Italian housing stock” developed by Cresme in collaboration with Symbola and promoted by Assimpredil Ance and the European Climate Foundation which was presented on 25 March in Milan. In addition to an estimate of the costs for the country system estimated at 319 billion euros for 3.2 million homes (superbonus panel), the study develops a precise simulation of the impact of the new EU rules on real estate units. And he takes two as examples, a single-family house and a condominium apartment. Let’s see them.

The calculation estimates

Two necessary premises. It must immediately be said that the simulation refers to the jump of two energy classes as envisaged in the first draft of the proposed directive. However, the example is still valid because the leap implies a reduction in emissions of 15% against the 16% set by 2030 in the latest version of the framework law voted in Stasburg. The second clarification concerns the calculation system. The Cresme and Symbola researchers used two cost estimation methods: the first cost estimation method is based on a Cresme survey on the 2023 prices of the different types of interventions and the different technologies that can be used for the interventions, the report points out; the results of this method would be used if the interventions envisaged by the EU directive were incentivized with building bonuses (basically the 50% currently in force for the “Home Bonus”). The second method is based on the average costs of the interventions resulting from the monthly Enea reports on the works carried out through the 110% superbonus; “These costs would be the most suitable to identify the economic commitment of energy requalification in case of use of enhanced incentives”, states the report. And now let’s get to the point.

Single-family house

The first simulation was conducted on an isolated single-family building, built between 1961 and 1975 in load-bearing masonry, of 120 m2 equally distributed on two levels «with a pitched brick roof, optimal orientation along the east-west axis, prevalent openings to the south (3 windows and 1 French window) and no openings to the west”, states the report. Apart from the advantageous exposure which allows you to gain heat in the winter (south-facing windows) and not receive excess heat during the summer (no west-facing windows), the building was attributed with the worst technical and plant engineering elements among those proposed by the Docet, which is the Enea application used for the energy certification of residential buildings with a surface area of ​​up to 200m2. The simulator intervened by assuming the worst energy requirements with a requirement of 731 kWh/m2 per year of global non-renewable primary energy. In this case the interventions and costs for the adaptation – and therefore for the reduction of energy dispersion – are not indifferent and are calculated on the average of the costs for each individual intervention but without VAT (see graph 1). They range from a minimum of 19 thousand euros (without VAT) for the sole replacement of the biomass winter air conditioning system which becomes 55,420 euros (again without VAT) for intervention number two, which involves the installation of a heat pump and external insulation heat on the walls. Here the economic impact of the bureaucracy and the construction site was also calculated which for scia/cilas, design and construction management varies from 6,820 euros to 9,620 euros, with an average of 8,220 euros. The biggest burden on the wallet is intervention 3, which involves the insulation of the walls and roof and the replacement of the windows. In this case the amount jumps to 85,803 euros (calculating VAT at 22% the final bill is 104,680 euros). «The payback times for the investments necessary to carry out the three types of intervention proposed, based on what was calculated by the Docet, are 9 years for intervention 1 which involves the replacement of the winter air conditioning system with a biomass system; 9 years for intervention 2 which involves the replacement of the winter air conditioning system with a heat pump and thermal insulation on the walls;
13 years for intervention 3 which involves the thermal insulation of the walls and roof and the replacement of the fixtures”, explains the dossier finally.

Condominium apartment

It’s better but the expense for a condominium apartment is still considerable (graph 2). In this case the simulation was conducted on an apartment in a large condominium with 32 interiors distributed over 8 floors, also built between 1961 and 1975 in reinforced concrete and bricks. The 120 m2 apartment is on the 5th floor, it borders the stairwell to the east and another apartment to the west, the openings are equally distributed between the south wall (3 windows and 1 French door overlooking a balcony) and the north ( 3 windows and 1 French door overlooking a balcony), explain Cresme and Symbola. Also in this case the worst technical and plant elements were attributed to it, resulting in an energy expenditure of 390 kWh/m2/year. The study suggests two types of interventions, not necessarily alternative and with distinct costs. The installation of a heat pump and new windows costs around 23,600 euros (without VAT, with VAT we are almost at 29 thousand euros) while the intervention with thermal insulation on the walls, replacement of windows and doors and condensing boiler make the bills soar to 48,464 euros without VAT. With taxes we go beyond 59 thousand euros.

The centralized heating plant

In the case of condominiums, the study highlights a third solution with a certain impact in terms of reducing emissions and more limited for the owners’ wallets: the centralized heating plant, «an intervention that leads to energy savings comparable – and in some cases superior – to previous ones (about 70%)”. This involves replacing the heat generator with a water-water heat pump powered by a low enthalpy geothermal source (open circuit or closed circuit). «The heat pump in this case, being mainly powered by a renewable source (and more precisely for 2/3 of its needs), would not present problems of burdening the electricity network and indeed, if the building were equipped with a photovoltaic system and electric storage battery, could even produce benefits in this sense.” In this case the cost per apartment would be around 19 thousand euros including the fee for the photovoltaic system and the storage battery. «It follows that the payback time of this intervention, for the same savings, is 18% better than the first simulation and 60% better than the second – explains the analysis -. Furthermore, the solution would allow the building to achieve a high degree of energy independence and to be able to maximize the convenience of possible collective self-consumption”.