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Villa a basso consumo energetico alle Sieci - Pontassieve - Firenze 
Progetto Architettonico ed energetico, direzione artistica

Impresa: Costruzioni Pieri, Firenze
Cliente: privato 
Costo: € 375.000,00

The projet consists in a low-energy semi-detached house placed in a very small sized triangular sloping plot. The plot is located in a hilly area of landscape value, slightly urbanized, named Le Sieci near Florence. The area consists of a part, free from vegetation, and a part with a forest of conifers and hardwoods. The building contains two independent apartments, each equipped with an individual entrance, a panoramic view over the valley to the northwest and an access to the garden to the south, where the plot widens towards the forest property. The strong constraints of the site determined the functional organization and volume, defined by three boxes stacked and staggered.


Low-energy and well-being
The proposed internal layout, and openings, were affected by the environmental performances that have a greater impact on psychological well-being: - Hygrothermal comfort in summer and winter - Indoor air quality - Natural lighting - Enjoyment of the landscape The size of the openings takes into account the use of space, increasing daylighting in day rooms. The summer sun protection of windows required a special study in order to minimize the need for mobile screens (blinds and curtains), especially in living areas, which requires the persistence of the view. The preference was for permanent shielding (overhangs and shelters) that allow the winter radiation for passive solar gain, and simultaneously provide effective protection from the summer sun. Indoor air quality is increased by the openings placed on the four cardinal points and by air extractor located in toilets, that allow a reliable and effective natural ventilation. The roof is partly flat, with terraces for the use and enjoyment of the landscape and with a''green roof'' that provides high thermal inertia reducing heat island effect, as well as an outdoor space to the attic; the roof is also sloping as a support for the architectural integration of solar thermal panels and part of photovoltaics. The building reaches the energy class A with a estimated consumption of 34.43 kWh/sqm per year.



Sustainable and Easy to do
The energy design has been set on the principle of availability of materials, simple design of technical systems and technical solutions, as well as easy maintenance. Therefore, the focus was primarily on a high performance envelope, leaving a secondary role to the plants and avoiding the high-tech. The winter thermal behavior, the acoustic behavior and the summer massive behavior of envelope has been maximized, preferring ''damp''solutions the know-how is widespread among construction workers in Tuscany. The innovation lies in the choice of simple technologies such as hollow bricks, for walls, and reinforced concrete lightened with polystyrene blocks, for floors, which alone provide the required transmittances. The thermal bridges of beams and pillars have been avoided from the design of envelope solution, and the minimum transmittances of law greatly improved with the addition of insulation: - polyurethane panels in the floors, for its durability, rigidity, breathability; - glass wool in the walls, for its characteristics of high breathability and sustainability (with a certified product processing waste glass and formaldehyde-free); glass wool was placed inside the wall that ensures effective protection and durability of the insulation. Finishes are planned with low-maintenance materials, such as aluminum high-energy performance frames and stoneware porcelain external paving, with EPD environmental certification; Other finishes are low-tech and low-cost solutions, such as lime plaster, highly breathable, or ''kilometer zero'', such as stone walls, made with stones from the nearby fields. The system of plants, very easy to do, consists of a condensing gas boiler and low temperature radiant floor panels. During the summer the radiant floor panels work with fresh water, whose temperature is lowered by heat exchanger using thermal gap of rainwater stored in the underground tank. The wood and its necessary maintenance ensures food for the fireplaces thath actively contribute to the reduction of energy consumption.

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