Eco-compatible buildings: cost-benefit balance

If you build or renovate in an environmentally responsible manner realize how much it cost the same jobs with traditional techniques would have probably already in the new era. Instead, despite the progress made in recent years, the construction techniques and innovative materials have yet to deal with a surplus of costs difficult to transfer to the final consumer in a scenario where the sales market still struggling and the front prices steady for a long time. But stifle innovation is mainly the difficulty of estimating the exact benefits achievable with each type of intervention and the timing of return on investment. For this reason we tried to put on the plate - through concrete actions - costs and savings, highlighting the shortcomings (on all the difficulty of finding appropriate professional) that still characterize the sector.

New building

The insulation size of 30% consumption for heating

Cost containment in the bill reaches the maximum results if the measures they take the path already in the planning stage, so going to create buildings that in itself minimize losses and are open to the use of renewable sources and subsequent optimizations. As demonstrated by the experience of a company Umbrian construction that a few months in Perugia has completed the first building in energy class A certificate Casaclima the region. A building with five apartments, "conceived before the recession," says the owner of the company, "when it was already clear the need to stand out from the competition to emerge." Build in an environmentally responsible manner by means, first, flip the priorities: "Usually you are designing on the basis of prevailing technologies, referring to the construction phase the search for the most suitable for the isolation," he explains.

"Instead, the objective of certification has prompted us to move in the opposite direction, dedicating an additional study at the design stage, so look for solutions from the outset with better impact on consumption and not to mention an analysis of costs and benefits, a must for any business-oriented market. " The backbone of the intervention consisted in the creation of a system for the insulation coat, "a measure that allows to reduce by 30% the cost of home heating." For another, the realization has uncovered during construction that the costs for the materials are even lower than traditional masonry cassette because it reduces the use of manpower. "The main difficulty was, however, represented by the shortage of professionals able to implement this solution," he adds, demonstrating that the skill shortage is a major (though little-known) limits the diffusion of green building in our country.

The net area of ​​500 square meters is heated, heated to a net volume of 1450 m3 (S / V of 0.63) and a heating requirement for the heating of 18 kWh / square meter per annum. The vertical closures are formed of blocks thermal thickness of 30 cm on which is fixed a thermal coat of eps (polystyrene and graphite) often 14 cm. The thermal transmittance value of total building system is of 0.16 W/m2K with a phase shift of 18 hours, essentially half the limit established by Legislative Decree no. 311/06 of 0.37 W/m2K. "The detailed study made in the design stage we did also detect a dispersion of heat between balconies, sidewalks and gutter around 20-25%." Hence the idea of ​​laying on the sidewalk a block made of vetrocellulare (60% recycled glass mixed with graphite), a solution that is unaffected by moisture, has a high resistance to crushing and has a good thermal insulation value. "This mixture has a very high cost, but a small amount is enough. In our case, we spent € 2,500 in addition, 1% of the total cost of construction of housing and facilities, but who will live there will rely on a drop in consumption for heating all around '80% of which 10% only thanks to this arrangement. " Also in this case the greatest difficulties occurred at the time of realization: "In the absence of national suppliers, we had to turn to a Belgian operator."

Existing home

The domestic consumption is cut down working on the dispersion

If the best results are obtained by acting already in the design phase, the urgency for those who already own is to find a solution that would reduce the weight of bills and air pollutant emissions. "In these it is recommended to aim first of targeted solutions able to reduce heat loss to the outside of the casing of the property". "For example, the fixtures and thermal bridges have an important impact on the loss," he adds, "but the quality of the intervention varies considerably, depending on specific conformations and the materials used and exposure. The recommended solutions in order to optimize technical and economic consist of the reconstruction of the surfaces that cause loss of heat between the inside and the outside of the house, "he adds. "For example, replace the threshold of travertine placed under the window, or the insulation of containers, has a cost of between 150 and 250 € per meter - the change depends on the size of the window (the larger, the lower the cost per square meter) - with a return on investment of between two and four years. " "Similarly, the replacement of fixtures of the old generation with modern windows to thermal cut is a minimally invasive solution and at the same time of great efficiency, in this case the payback the investment must be evaluated case by case depending on the specific needs of ' redevelopment energy. " For the purpose of providing modern technology allows you to intervene in a timely manner according to the state of the property and wishes of the user: "The replacement of traditional incandescent lighting systems with energy-saving lamps, halogen or LED produces types, in the face of limited investments, a minimum return on investment, even less than twelve months. "The same applies to the production facilities of the heat," for which - depending on the type of property - can be made of the specific choices as condensing boilers and heat recovery systems that lead to a reduction in fuel consumption and emissions that starting from 20% to 45%, "he concludes.

Building a business use

With the intervention of Esco heating business is at no cost

"In the case of an industrial building the greatest room for maneuver regarding the reduction in the energy consumption of heat and electricity." "These are companies that do not sell a product or service," he explains, "but the purpose of which is to invest in technology solutions for saving energy with the aim of sharing the results with you." For energy-intensive businesses, such as food industries, dairies and paper mills, suggests the construction of a cogeneration plant, "from which comes all that the establishment is electricity, the heat." Considering a structure type 1 megawatt, "the cost of construction is around one million Euros, with a return investing approximately four / five-year useful life of 15". In cases like this is the same Esco making the investment (for which the facility at no cost to the employer), in exchange for a portion - usually between 50 and 60% - of the cost savings achieved. This would be the classic Egg of Columbus - in the sense that benefits everyone - if there was a limit: the numbers of the example are confirmed in reality only under certain conditions (including high consumption of electricity, steam and hot water ), which are assessed on a case by case basis.

 

15/01/2011

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Translated via software

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Source:

Italian version of CercaGeometra.it