Passive houses
Most energy-efficient type of housing, healthy and high quality indoor environment, pleasant temperatures on hot summer days, even in the most frosts, constantly fresh air. These are the basic features of a passive house, which is obtained in compliance with simple but effective measures. All at a minimal additional cost compared to a conventional building.
The principle is:
consistency and logic of the proposal
meet the basic criteria and requirements for passive houses - specific heat demand for heating max. 15 kWh / (m2a) airtightness n50 max. 0.6 1 / h specific primary energy max. 120 kWh / (m2a)
utilization of heat gains from the sun, appliances and people
respecting the laws of building physics
the use of energy from renewable sources
quality execution
Why choose a passive house?
extremely low heating costs
more comfortable life
a constant supply of fresh air
do not form the draft
no temperature difference in the room
pleasant temperatures in winter and in summer
Eco-friendly living to nature
modern trend - in Germany and Austria to 50% of new construction
What is required (in brief) for a passive house?
a thick layer of insulation
compact shape
high-quality windows and frames
airtightness of the building
effective ventilation with heat recovery
reduction of primary energy
Thermal insulation passive houses
Passive House has an extremely low heat consumption. To do it could deliver a minimum amount of power, and yet it remained thermal comfort, it is necessary to protect the heat in the house. A thick layer of insulation without thermal bridges significantly reduces heat loss.
Unless you want to achieve the passive standard, forget variant walls without insulation. Ensuring ventilation and air exchange is for passive houses always ensure recovery, so that myths and superstitions that house "breathing" are mere ignorance of the issues.
The supporting structure consists classic materials (e.g. brick, vápenopísek), preferably with a good heat accumulation and insulating material on the outer side wall forms a polystyrene or façade rockwool. To get to the passive standard, be aware that the minimum thickness of the insulator is 300 mm, which means using two layers of insulation with proper anchoring. The surface of the facade forms a thin plaster in the interior is then used best finish on the material carrier.
For ventilated insulation systems is inserted between the insulation supporting elements of the grid, which is secured to the carrier walls. Several crossover grid is suitable due to the elimination of linear thermal bridges. Another important part of the system is purged gap thickness at least 25 mm, the distances forms another part of the grate - vertical battens. Covering part of the air gap creates a facade cladding - wood, fiber cement, ceramics etc.
The compact design of the passive house
The ideal shape for a passive house is a sphere. Build a house with this shape, however, it is rather difficult and input cost would be very high. That is why we are trying to build houses with a real shape so that the building shaped simple as possible.
Each corner in addition, or corners, not only increases the cooling area, but also increases the risk of thermal bridges. But if we insist on architectural complexity, it is necessary to further insulate the house so that the average coefficient of heat structures as low as possible.
Windows and frames for passive houses
The passive house windows are the weakest link in the overall thermal envelope of the building. That does not mean that we have to minimize them.
Indeed fulfills two important roles: not only allow us to X-ray room, but also contribute significantly to savings in heating energy. The energy that gets through the windows into the interior, reducing the need for heating. This is especially useful in winter.
Conversely, in summer when the sun is more, we have to reckon with some of shielding systems. These systems may operate aesthetically, e.g. overlap balcony. Or we can replenish window blinds or shutters. Achilles' heel of the window consists of a frame that is necessary to insulate well (best break lining exterior parts).
Even so, it is important to choose a frame with excellent thermal insulating properties and it does not matter whether plastic, wood, or a combination. When choosing a window, it is important to focus on the overall heat transfer coefficient, ie including the frame, which should not exceed 1 W / (m2K). As with low-energy houses, and even passive houses, we use a system of multiple glazing. The minimum is to use double glazing, most often triple, which are filled with argon or krypton.
Today, as part of the glazing using heat mirror or if MirrorTM Heat, which is a polyester film coated with special layers of metal oxides, whose location is in the middle layer between the panes. This application significantly improves the heat transfer coefficient of glass, but the purchase price of such a system glazing is somewhat higher. Some windows can be designed as neotvíravá.
This will improve the overall thermal characteristics of the window, but on the operational aspect of the proposal (possibility washing windows, possibility of escape).
Air tightness for passive houses
Basically, in every house we wanted to achieve a certain airtightness, or airtightness, the overall building envelope.
So how low-energy buildings, and especially in passive houses have to create a continuous airtight envelope and thus prevent not only heat loss, but also to ensure the proper functioning of ventilation equipment.
In massive structures not ensuring airtightness big problem, bigger part eliminates well-executed finish plaster.
The most critical points are found mainly in windows where contact materials quite often underestimated. Appropriately designing the overall song structure and using vapor barrier adhesive tape or special collars can prevent problems. The film is also used to arrest the flow of moisture inside the structure can cause considerable problems.
To properly check whether we have the passive construction, sealed well, serve us with a special measuring device that is placed in the front door. Building inflates and measurement is carried out.
At constant pressure of 50 Pa per hour should not replace leakage amounts larger than 0.6 times the volume of air in the entire measurement object. This test is called a blower-door, or if you want to test airtightness.
Ventilation and heat recovery for passive houses
Ventilation escapes from the interior of a large amount of heat. In a passive house to opening windows or do not remember, because it provides a fresh air ventilation system with heat recovery, professionally speaking, controlled ventilation system with heat recovery.
The device automatically sucks in fresh air from outside and brings it inside.
While the air passes through a filter which removes pollutants and it before entering the room still heats to room temperature. The air that leaves the room through a heat exchanger passes a large part of the heat and air supply. The effectiveness of these so-called heat exchangers is about 95%.
It means that the reheated either electrically or warm water, you only have the remaining 5%. And that's a big saving heat. The house is always fresh air, which is due to quality filters free of dust, pollen and other impurities, which is an important factor for allergy sufferers.
The entire system is held in the floor or ceiling. However, the system is constructed so that the house you are nothing but pipe. The air inlet in the residential area (rooms, bedrooms, living room) located using diffusers on the floor or in the wall just above the floor.
Exhaust air is in the central area (hall, corridor) and logically where we need to exhaust pollutants and moisture, ie toilet, bathroom, kitchen, and possibly in the locker room. In these rooms can be lowered ceiling and so it is ideal to place the suction head into the ceiling design or just below the ceiling.
The ventilation unit is most often placed eg. In the utility room, where there is such a high demand for sound insulation, but the overall operation of ventilation is practically inaudible. The perfect effect it is appropriate to combine the unit with air geothermal heat exchanger, which is essentially a pipeline buried approximately 2 m below ground level.
During winter, it works as a natural protection against frost and vice versa during the summer allows pre-air and improved thermal comfort in the building. It is due to the fact that at a depth of 2 m is a constant temperature of about + 10 ° C.
Primary energy for passive houses
In terms of the overall energy balance of the building it is not only an important energy consumption measured at the entrance to the building.
To this must be added the quantity of primary energy, which had to be for that purpose in a power system released and transported to the place of consumption.
For example, for heating electricity is the primary energy to four times higher than while using renewable resources. Simply put, if we use solar panels or biomass boiler, thereby dramatically reduce primary energy.
