ENERGY IMPROVEMENT OF BUILDINGS

ENERGY RETROFIT AND ADDITIONAL STOREY OF A TWO-FAMILY RESIDENTIAL BUILDING
The owner has expressed a desire to improve the energy efficiency of his building, a villa with two apartments built in the Province of Como in the first half of 2000, with concrete structures and brick walls and, at the same time, take advantage of the opportunity given by the regional and municipal rules, to recover the attic, thus obtaining a widening of one of the two existing units.
The choice fell on laminated wood for the structure of the new roof and reinforced concrete and brick, for the building of the vertical structures and of the perimeter walls, all construction techniques already in use in the existing building.
Of the two solutions proposed in the energy audit, the client chosen the most efficient, in terms of energy, as follows:
  1. Pitched roof timber: thermal insulation with wood fiber (thickness 28 cm), which ensures high performance and comfort both in winter and in summer;
  2. attic: thermal insulation with mineral wool (thickness 20 cm);
  3. exterior elevations: thermal insulation with polystyrene with graphite (thickness 20 cm);
  4. basements: inner thermal insulation with panels in Stiferite (thickness 12 cm);
  5. windows: larch wood with triple glazing, with noble gas and low emissivity treatment, darkening system with wooden shutters, already present in the existing building;
  6. door entrance: armoured with high thermal performance (Ud = 1.1 W/mqK);
  7. solar blinds: placed on the south elevation, aimed at limiting the direct sunshine in the summer and the consequent overheating of the interior.
  8. Particular attention has been given to the solution of various thermal bridges determined by the original building, particularly at junctions floor - wall.

For the the technological plants has been provided:
  1. heat production: kept the two existing boilers, with a natural gas;
  2. diffusion and heat setting: maintained the existing cast iron radiators with area thermostats; added thermostatic valves for temperature separation of the individual rooms;
  3. production of heat: wood stove soapstone;
  4. heating and cooling of larger apartment: split system with reversible heat pumps;
  5. controlled mechanical ventilation: two technological plants planned controlled mechanical ventilation, with heat recovery with high efficiency;
  6. domestic hot water production: combined boiler, solar panels and buffer tank;
  7. photovoltaic solar panels: two plants installed on the roof of 3 kWp (the small house) and 4,5 kWp (for housing larger, extended composition);
  8. appliances: electromagnetic induction plates.

At the conclusion of the work, in addition to high levels of comfort found, it was noted a marked improvement in the energy management of the entire building, so that in the first winter it was possible to heat the entire widened apartment, depending on the external environmental conditions and related affordability, radiators and boilers to natural gas, with split and reversible heat pumps, stoked, the latter, using self-generated electricity with photovoltaic panels (contractual system – Scambio sul posto) or, alternatively, the stove Soapstone.
The good result of the intervention was also confirmed by the energy certification, obtained by the two houses with Cened Protocol:
  1. Widened apartment: Energy Efficiency increased from Class "E" (Eph 132.39 kW h/mq a), to Class "A +" (Eph 12.75 kW h/ mq a);
  2. Small apartment: Energy Efficiency increased from Class "G" (Eph 230.41 kW h/ mq a), to Class "A" (Eph 16.49 kW h/ mq a).

The building has received the following tax benefits, that will significantly reduce the payback period of the investment:
  1. tax breaks for building renovations (deduction 50%);
  2. tax breaks for work aimed at energy savings (deductions 55 and 65%), both for the building envelope for the installation of solar panels;
  3. tax incentives for the installation of photovoltaic panels.
TYPE OF INTERVENTION: Energy retrofit and additional storey

TYPE OF USE: Residential

LOCATION: Lombardy

SIZE OF INTERVENTION: 270 sq.m.

ENERGY CLASSIFICATION: Class A + and A - Cened Protocol

DESIGN - PROGRESS: 2012 – Works completed in 2014
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