The construction is always passive
A lot is said about the standards NF15 and NF40 (known also as EUco<15 and EUco<40), which define the overall demand for energy used for heating and ventilation of one square meter per year. These parameters are respectively 15 kWh / m2 / year and 40 kWh / m2 / year. However, these are the standards defined under current regulations change, which is expected in connection with the implementation of European directives 2012/27/EU and 2010/31/EU, as well as earlier ones, which now are already used or implemented in practice in Poland.
The National Fund for Environmental Protection and Water Management (Poland) supports activities aimed at the use of appropriate energy standards in new buildings as providing subsidies for investment.
In practice, to get a first threshold of a grant, the building must meet the requirements for NF40, but there is nothing to prevent the values closer to the lower demand of energy, for example at the level of 20 kWh / m2 / year. Many people choose such a version, calculating the value of the subsidy in relation to the amount of expenditures that need to be incurred to complement standard NF15.
The problem is the use of traditional systems that are tailored to the requirements of passive instead of using the technology, designed with the aim of passive houses. The requirements for buildings are unrelenting, and the coefficients reveal the weaknesses of the systems, which have been used for hundreds or tens of years. For example, the requirements for external walls in standard NF15 stand at Umax = 0.12 W / m2*K, the same for roofs. In turn, the ceilings should have a conductivity of not more than Umax = 0.15 W / m2*K. For example, according to data from the calculator of thermal transmittance to reach the permeability coefficient of 0.11, using Porotherm 38 DRYFIX one needs to use as much as 20 cm of polystyrene in passive houses, ie with low conductivity coefficient of 0.032. This gives the thickness of the wall with insulation up to 58 cm and when it comes to elimination of thermal bridges in places where rates are disturbed, it is even more. In contrast, our system with a standard wall designed for NF15 has a thickness of 36 cm and with easily achieved coefficient of 0.11. Importantly, our walls do not need further warming – the construction is simply passive.
An important factor in the construction of passive houses is also the amount of thermal bridges and coefficients characterizing them as well as their effective reduction. Our design virtually eliminates the occurrence of thermal bridges by the continuity of the insulating layer in the external walls and their connections.
The main advantages of the structure should be:
– Elimination of bridges on the joints frame-jamb, down shutters, door thresholds for balcony and input
– Connections occurring in roof windows
– Connection of external walls with a roof
– Connection of ceilings above unheated basements of the external walls,
– Switching places of external and internal walls
In conclusion, our patented construction is always passive, so even the use of other elements, such as cheaper windows, doors or lack of heat recovery do not reduce so much parameters of energy efficiency of home, which may be an intermediate solution for those who wish to combine classic effects of passive solutions and thereby reduce the cost of home maintenance.