KOFINAS Passive House

Based on the needs of the modern era for energy savings, in the company KOFINAS Prefabricated Houses we follow construction practices of reduced energy consumption. Our constructions have been distinguished according to the Energy Efficiency Regulation of Buildings (KENAK) as energy class A ‘houses, while our guarantee is the model building, the so-called “Passive House” KOFINAS.

What is a Passive Home?

A passive is the house that meets all the conditions to be characterized as fully energy efficient and environmentally friendly. Specifically, a Passive House offers high energy efficiency, economy and sustainability, with minimal energy requirements and costs for heating and cooling.

According to the official definition by the German Institute of Passive Building, “The passive building is a building in which the internal thermal comfort (ISO 7730) is ensured exclusively by preheating or cooling the amount of fresh air required (DIN 1946) for proper indoor atmosphere, without the use of additional air recirculation. ”

The company KOFINAS Prefabricated Houses as an official member of the Hellenic Institute of Passive Building, is active in the design and construction of Passive buildings with the corresponding official institutional certification, combining the quality constructions of the company with data of sustainability and comfort!

What are the benefits of a Passive Home?

Energy Efficiency

Through the passive heating and cooling system, the Passive House has the ability to maintain the correct and desired temperature inside all year round, regardless of the climate zone in which it is located. The fact that a Passive House uses alternative heating and cooling methods, such as solar energy, indoor heat sources, natural ventilation, etc., makes conventional heat and cooling sources that consume huge amounts of energy, completely useless and inefficient. Precise design, properly selected materials and of course the modern passive heating and cooling systems, offer to each tenant / user of the house the best healthy living conditions without humidity, ensuring a constant temperature.


The Passive House operates by reducing heat loss and securing thermal gains. Due to the bioclimatic design of a passive house, its percentages of energy consumed in one year are obviously reduced compared to the data of a conventional house. Relatively, the energy required for heating and cooling in a Passive House is up to 90% less. Due to this, the emissions of pollutants that drastically affect the greenhouse effect are significantly reduced. Thus, the choice of a passive house can be characterized as one of the most sustainable building and living options, with low environmental impact, since the primary energy used is extremely small.

At the same time, it is important to mention that in relation to a conventional house, the additional energy required to achieve the heating and cooling of a Passive house is negligible if we consider the savings data they offer. Typically, according to EIPAK, “in a passive house, less than 1.5 liters of oil or 1.5 cubic meters of gas per year is required to heat a square meter of living space”.


In a passive home, saving money is evident from the beginning of life. Minimum energy requirements reduce to the maximum the necessary operating costs, which in contrast to conventional houses reach heights both for heating in winter and for cooling in the warmer months.

At the same time, what is certain is that every tenant / user does not need to worry about unnecessary expenses or when the initial amortization of the initial investment will take place, since the cost of a passive house is extremely affordable. Specifically, in the company KOFINAS prefabricated houses, the cost of using the highest quality building materials and construction of a passive house, is directly balanced by the reduced operating costs and the long-term energy efficiency.

Comfortable living

As mentioned in the official definition of the Passive House, the main result and benefit of the passive cooling and heating systems, is to ensure a healthy and proper indoor atmosphere. Indeed, due to the way these systems operate with air filter, automatic humidity adjustment, prevention of mold and damage it may cause, the atmosphere inside a passive house becomes the most suitable for optimal living and excellent quality of life. The fact is, how the passive house contributes to the health of the users while at the same time it is an absolutely practical and quality choice, since it does not require constant intervention for ventilation, heating, cooling, hot water etc.

What are the basic principles of operation of a Passive Home? 

The operation of a Passive House is based on 5 basic principles of design and construction, related to the exploitation of free energy and heat.

More specifically, the so-called “free” heat is produced mainly by electrical appliances that are used daily in a house. In order to be able to immediately utilize and reuse this heat, for the purpose of the desired heating, the passive house must follow the following 5 specific modes of operation:


As mentioned, the heat generated by electrical appliances can be stored in a passive house and thus reused for heating purposes, without unnecessary energy requirements and losses. In order to make this possible, it is necessary to take care of the complete insulation of the house, so that the building shell is completely airtight to keep the heat inside during the winter months and to be prevented accordingly during the summer.


Quality windows of a passive house play an equally important role for its maximum energy efficiency. In particular, windows with insulating design, equipped with low-reflection glazing are fully necessary to prevent the inflow or outflow of heat.


In a passive house, the maximum airtightness of the whole construction is provided in order to minimize possible leaks through openings and thus to increase the energy efficiency levels.

Absence of thermal bridges 

With proper and careful insulating shielding of the entire passive house, the goal is the absence of thermal bridges that are often responsible for the development of moisture, mold and corresponding damage. This creates the conditions for a comfortable living, in a perfectly healthy atmosphere and safe environment.


A key factor in the operation of a passive house, of course, are the ventilation systems that are integrated for maximum energy efficiency and the regulation of air, humidity and heat that enters the building.

In practice, how does a passive house work?

  1. A ventilation system with an air-to-air heat exchanger is installed so that it can simultaneously bring fresh air from outside and at the same time release a quantity of stale air from inside the building.
  1. During the winter months, the cold outside fresh air enters the heat exchanger, receives the heat of the exhausted stale air and enters the passive house. Specifically, the hot stale air that leaves the house, “brings” the “free” heat, which through the exchanger heats the fresh air that enters the house.
  1. In summer the exhausted stale air cools the warmest incoming fresh air, maintaining proper cooling levels inside the house.
  1. In case the above system is combined with geothermal energy (the fresh air diffuses first from the earth and then goes to the exchanger), the profits and the general energy benefits are multiplied for both winter and summer.

As a result of all the above, the installation of a conventional heating and cooling system can be avoided and the house can function fully efficiently through the mechanical ventilation systems for absolute energy efficiency.

What is the cost of a Passive Home?

Based on the data and specifications of the company KOFINAS Prefabricated Houses, it is important to mention how the cost of a passive house of 100 sq.m. is about 10% larger than that of a typical construction of our company.

This difference is obviously insignificant, compared to the long-term savings offered by a passive home due to the minimized operating costs since the amortization is done immediately and the benefits become obvious from the very first moment, both in energy and financial level.

Certification of the company KOFINAS for the Passive Home 

A basic condition for designating a house Liabilities is to test in practice all its functions in order to check whether it meets the basic principles of how to organize a passive house.

The company KOFINAS, which as it has proved is most interested in the scientific certification and guarantee of all the practices and technologies it utilizes, has been submitted to the certification process for the Passive Home.

The certification criteria for passive homes are set by the Passive Housing Institute, based in Darmstadt, Germany.

After a series of detailed scientific tests, it turned out that the company KOFINAS follows all the necessary design and construction standards of the passive building, in order to provide all the energy and practical benefits to its customers.

Are you interested in building your own prefabricated house according to the best and highest quality specifications of the market?

The company “Kofinas” is certified by Greek and international agencies for all the materials it uses and for the manufacturing process that follows.

In this way, our constant quality and reliability is proven, which characterizes every construction of “Kofinas” from 1977 until today.

Contact us, and we will undertake to make the prefabricated house of your dreams come true