Fixtures: energy efficiency, tax deductions, legislation and certifications to ensure the correct insulation of doors and windows.
When it comes to energy efficiency of doors and windows many problems have to be faced: the windows must provide lighting and ventilation as well as the doors that give to the outside allow entry and exit from the building, we are talking about points of discontinuity in the entire building structure.
By replacing the fixtures, an energy redevelopment of the building is carried out, thanks to which there are three advantages:
- Increased living comfort
- Possibility to access tax deductions (Ecobonus)
- Energy saving on your bill, see: energy saving with fixtures
The technological solutions currently available on the market open the door to a more effective one insulation of the fixtures. In ascending order of price and thermal insulation offered, we have:
- Laminated glass: double or triple glass.
An air chamber increases the "U Factor" and therefore the thermal and acoustic insulation offered.
- Glass with shielding film
It is laminated glass with the addition of shielding films capable of reflecting heat.
- Solar control glass: reflective or selective.
It is able to reduce thermal loads from radiation.
- Low emissivity glass
It is a solution that is able to reduce radiative exchanges with the outside by means of a thin metal film.
Just like the glass, even the proper windows cause heat loss, just think of the classic drafts of doors and windows. The cheapest fixtures are those in wood, immediately followed by fixtures in polyvinyl chloride (PVC) and fixtures in metal, among the most common ones in aluminum. For excellent insulation, the best combination involves the use of wooden frames associated with low-emission glass. A insulating window of this kind (with wooden frames associated with a low-emissivity glass) has an indicative price ranging from 300 to 500 euros for sizes of 80 - 120 cm. The lowest prices are obtained with windows in pvc and laminated glass (double glass).
Energy efficiency of windows and tax deductions
With the replacement of the fixtures, a revaluation of the building is carried out which, according to the Stability Law, can be incentivized by means of a tax relief set at 65% if the intervention is carried out by the end of 2015. Tax deductions for the replacement of doors and windows drops to 50% for interventions carried out in 2016 and to 30% if the replacement with insulated windows and insulated doors is carried out in 2017.
In order to access the deductions, the intervention must be configured as a replacement or modification of existing and new elementsdoors and windowsinstalled must be characterized by certain values ofthermal transmittance marked by the unit of measurement Uw. Thermal transmittance is nothing more than the amount of heat dissipated through the fixtures.
For the calculation of the thermal transmittance of doors and windows, please refer to the booklet made available byNational Agency for Energy Efficiency, available for download in pdf format at the end of the page.
Theenergy efficient fixturesare certified by the manufacturer to guarantee the real performance they offer. Almost like a light bulb, the fixtures also have an energy certification. The certification of the fixtures examines the thermal transmittance of the glass and frames without forgetting the installation context. Therelegislationin force onenergy efficiencyof fixtures and their certification also examines the climatic bands. The legislation provides for thermal transmittance limits based on the location where the fixtures will be installed. The law also provides for a difference between newly built homes and those undergoing simple renovation
In order to evaluate theenergy efficiency of windows, the end user, after installation, can perform a thermographic analysis or the so-calledBlowing Door test. These are tests that can detect any residual criticalities in the face of an energy revaluation intervention. These tests become mandatory if the user intends to access the tax deductions provided for by the eco-bonus: in this case an energy certifier must issue the document of the building's class both before and after the installation of the new fixtures.
Files to download: Calculate the thermal transmittance