The ecological house? Economical that is!
Sustainable construction is becoming increasingly important.The newly constructed buildings use technologies and products that ensure the lowest power consumption possible.The existing building are already subject to thermal performance improvement.This makes them less burdensome for the environment and yes, less heavy on the wallet.What sustainable construction really is?
Energy-efficient buildings include low-energy and passive houses but also those in which energy consumption amounts to nearly zero. They are called the nZEB – Zero Energy Buildings. What are the differences? Buildings have their energy standard, which shows their annual energy consumption. For the energy-efficient buildings, the standard is NF40 - EUco<40 kWh / (m2 per year) for passive houses: NF15 - EuCO<15 kWh / (m2 per year). As for the nZEB buildings, the standard reaches 0 kWh / (m2 per year). However, it is good to bear in mind that in addition to these, there are buildings with positive energy balance. This means that within a year they produce more energy than they consume.
A passive building? What is it?
Not everyone may be familiar with this term. These buildings have low energy requirements for heating purposes. Passive buildings consume no more than 15 kWh/m2,which corresponds to 1.5 m3 gas per 1 m2 of the surface. The level of primary energy consumption in this kind of building cannot exceed 120 kWh/m2 per year for all energy needs, which include heating, hot water and electricity consumption needed for living.At the same time, in residential buildings, the energy consumption (heating only) is up to 120 kWh / (m2 year) – says Piotr Piątek, Engineer and Thermal Calculations Specialist at Aluprof. The demand for energy in passive buildings is eight times smaller than in traditional ones.
The essence of the energy-efficient buildings is to minimize energy loss.Here, each stage is of importance, whether we choose a right plot, a suitable project, and this until the very last details such as installing a window sill. A passive house is above all perfectly insulated house that prevents heat from escaping – explains Piotr Piątek from Aluprof.
Passive houses – what makes them different
The entire external layer of the passive building is air impermeable. However, the heat transfer coefficient (U) of the walls must be lower than 0.15 W/(m²K). This type of building requires appropriate windows, since untight window frames may lead to up to 30% of home’s energy loss. That is why the windows’ heat transfer coefficient should not exceed Uw= 0.80 W/(m²K). Passive houses often come equipped with a ground heat exchanger and a recuperator. These devices allow to regain the heat from air conditioning and hence reduce home energy loss by 75 – 90%. Solar collectors are becoming increasingly popular, and the energy they collect may be used to heat the tap water or provide 25 – 35 % of the energy for space heating purposes.
What might come as a surprise, passive buildings use a large amount of glazing (windows, glazed façades, etc.). Glazed areas are installed mostly at the southern side of the building and are practically absent from the northern, as the passive solar gain is usually rather low in there. Today, the energy-efficent windows can greatly reduce the heat losses and enable the maximum daylighting of interior spaces.In addition, they provide free solar energy to heat the rooms – explains Piotr Piątek from Aluprof.
Passive house – how much does it cost?
Building a passive house is more expensive than a traditional one, but this should be considered as a one-time investment. It will however pay off through low bills during the entire building’s life cycle. Building a passive house may cost zł.700 to zł.1000 more for each m².Energy-saving technologies allow for savings up to 80% on heating bills.We should also pay attention to the fact that the prices of gas and electricity rise every year – says Piotr Friday from Aluprof.
To encourage the Poles to build “ecologically” and “economically”, the National Fund for Environmental Protection and Water Management (NFOŚiGW) has launched a programme of subsidized loans for energy-efficient houses. The amount of a single “grant” can go up to zł.50,000 for buildings that reach the required energy standard NF15 – EuCO 15 kWh/(m2 per year) – this concerns passive houses. Bonuses will be paid upon completion of the construction and after the relevant inspection – for the building must comply with the required parameters.
All the more reason to capitalise on a house that is more friendly to us and to our planet, and reduces energy consumption for heating, lighting and air conditioning.
Aluprof’s energy-efficient systems have been used in many passive housing investments, in both residential and commercial buildings. A residential building in Berlin, located at Lutzowstrasse, uses MB-86 Aero (with aerogel) and MB-TT50 systems. Other Aluprof solutions: MB–70 HI and MB–SR50 HI systems have been used to build GPP Business Park in Katowice, Poland. This office complex has been awarded with a prestigious distinction at the Green Buildings Awards Gala. Another energy-efficient building that uses Aluprof systems (MB-SE75 unitized façade and MB-TT50 mullion-transom façade) is Alchemiaoffice building in Gdańsk, Poland.