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This diagram displays the variations in quantity and quality of the energy balance of a house. Although passive houses theoretically have balance between supplied (QG) and consumed (QV) energy, i.e.:


they require a heating system which will maintain that balance when extreme temperatures occur at any time of the year. The minute requirement for heating of the passive house can be satisfied in many ways like for example by means of: solar and earth collectors, accumulating tanks, heat pumps etc. The economic benefit determines the choice of a heating system.

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Already in 2006 „MEGAMAT LTD" recognised the potential of heat pumps as a heating technology of the future and directed its efforts together with “Unitherm Ltd” towards their introduction in our country.
Heat pumps utilize in a most effective way (Coefficient of performance СОР = 4,5) the energy of the sun accumulated in the earth, water or air to provide heating, cooling and hot water for the home all through the year. The choice of one of the ways for obtaining energy from nature depends on the characteristics of the terrain. We install and maintain the most reliable and effective heat pumps of the leading Swedish company “Thermia”.
„MEGAMAT LTD" is the only company in Bulgaria that produces earth collectors which are placed horizontally or vertically at about 2,5 m under ground.
These collectors deliver in a most profitable way the energy of the sun accumulated in the earth or water for heating during winter and passive cooling in summer.

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The use of direct solar energy by means of solar panels for supplying hot water for household needs gains more and more popularity.
But the investment in them is hardly profitable if they are used only to supply hot water for the household. „MEGAMAT LTD" uses the opportunity for mounting the solar panels into the roof and walls and in this way we considerably reduce the initial investment.
By means of accumulating tanks the heat energy of the sun is used for heating in winter.

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The application of an accumulating tank considerably increases the opportunities for storage and dephased use of:
- solar energy for heating.
- energy from the earth for passive cooling.
- the warmth from a fireplace, gas or solid fuel boilers.
- the energy accumulated during the night and any other energy obtained economically profitable.
The accumulating tank is used for passive cooling of the building in summer through the direct exchange with the cool in the earth extracted by the earth collectors.
Thus in winter and summer the accumulating tank provides passive air conditioning of the house.
This method of conditioning of passive houses which takes into consideration the climate characteristics in Bulgaria adds more meaning to the term “passive house” than there is for the houses in western Europe.
The fully equipped and insulated tanks are transported and installed together with the earth collectors by our company.


The firm uses water or air as a heat carrier to distribute the heat in the rooms of the house.

Heat carrier – water
The systems which use water as a heat carrier have their coils placed on the floor, walls or ceiling and they provide both heating and cooling.
Тhe systems installed in this way transmit radiantly heat, respectivelly cold in the building. Beside the economic benefit of the low temeperature heating it creates an exceptionally wholesome temperature comfort in the whole room.

Heat carrier – Air
The use of air for ventilation and conditioning of the rooms considerably simplifies the system. The heating, respectively cooling of the air is performed by a heat carrier which gains energy from earth. Due to this energy the filtrated and fresh incoming air is delivered at the necessary temperature of 14 - 22 ºC.
The outgoing air gives off its heat to the incoming in the energy recovering device. In an electrical or water heat - exchanger the incoming air can be heated to the necessary temperature ensuring the heating of the house.

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According to Bulgarian standards ventilation is not required. In passive houses, however, it is a substantial part of the energy balance and is extremely important for creating a wholesome inner climate.
The traditional way of ventilating the rooms by opening the windows is ineffective and leads to big heat losses and for this reason in a passive house it is replaced by controlled ventilation and effective heat recovery.
The incoming air, rich with oxygen, is cleansed from dust, flower pollen and microorganisms and is delivered to the rooms heated at about 20 - 22ºС . The outgoing foul air takes away the extra humidity and smells after it has already given off 50 - 90% percent of its heat to the incoming air in the heat recovery device. The precise planning of the ventilation system guarantees noiseless ventilating of every room with 0,3 times exchange of air. The harmful condensation and mould are impossible to appear in a house built by us. Most of the time during the year the minimal amount of heat needed for reaching the adequate temperature is provided by the incoming air.
This air is heated passively by the temperature of the earth and warmed additionally by the outgoing air in the heat recovery unit and the heat-exchanger after it. Economically this is the most efficient way to do ventilation and heating. Cooling of the house is done in the same passive way by taking advantage of the relatively low constant temperature of the ground.

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The electrical and water supply installations are designed according to every project. The parts of the installations which will be placed in the separate components like for example, the foundation, walls and volumetric modules are fitted in advance during manufacturing of the components.


We offer mounting of photovoltaic installation in the walls or roof, which taking into consideration the reduced energy consumption can make the passive house completely independent from the power supply.