Wood is one of the oldest building materials in the world, offering incomparable warmth and comfort for entire generations.

Low Energy Houses


What is a low energy house?

It is any type of house wherein the indoor temperature of 20°C can be reached without using any standard heating and cooling systems. Such buildings are also known as passive houses because the prevailing heat sources are passive, e.g., solar heat, the heat emitted by people and appliances, etc. More heat, if necessary, can be obtained from the use of a controlled ventilation system.
The basic features of a passive house are as follows:

  • Compact form
  • Superinsulation
  • Southern orientation and shade considerations
  • Perfect building envelope air-tightness
  • Passive air heating systems
  • Highly efficient heat recovery from exhaust air
  • Hot water supply using regenerative energy sources
  • Energy-saving household appliances.
The schedule and implementation of the plan in compliance with the passive house requirements should be guided by the basic holistic approach defined by Aristotle in the Metaphysics: "The whole is more than the sum of its parts".

We offer our clients investment in home constructions - foundation, wall and roof insulation. This is a onetime investment meanwhile heating costs are daily and ever-increasing. The key criterion for a low energy house is the building air-tightness. Air-tightness prevents heat loss.
This is the house we built to our customer in Denmark. This house is of a cost-effective rectangular shape and the space inside the house does not exceed the height of 2.50 m. It is oriented toward the south where stained glass windows are installed. A special glass and window structure prevents the inside of the house from being heated by sunrays even on a hot summer day whereas in winter when the sun rises lower, the inside of the house gets enough light and an adequate quantity of heat.
Unless the house is air-tight, huge amounts of energy are lost due to excessive air filtration. Most heat is lost due to improperly installed foundations, external walls, roof constructions and poor quality windows therefore we offer our customers to focus on the given structures.
We produced 43-cm-thick external wall elements with thermal resistance R - 9.80 (0.1 W/m2K) and 53-cm-thick roof elements (thermal resistance R - 12.60 (0.08 W/m2K)) to our customer in Denmark. In accordance with the recommendations adopted in Germany, it is desirable that the heat transfer coefficient U for outdoor partitioning (walls, roof and floor) does not exceed 0.10 W/K (sq. m.) in a passive house.
The air leakage test of the building ("Blower Door Test") was performed on the initiative and at the expense of our Danish customer. The results were excellent. Certificate.

What is the air leakage test of the building? It is a diagnostic test to determine the building air-tightness and to trace air leakage sites. During the test, an air flow resulting from creation of pressure differences between the inside and outside by means of a special fan is measured. The air flow (m3/h) is measured at the pressure difference of 50 Pa. The air change rate is determined by dividing the internal volume of the building by the measured air flow. Typical air change rates:

  • for a leaky house n50 > 3 h-1
  • for a low energy house n50 > 1,5 h-1
  • for a passive house n50 > 0,6 h-1

If we took into account a long-term perspective, we would realize that the construction of a passive house is cheaper than that of a traditional one so do not try to save on the most important things!

Passiv House Pictures

We are glad to see this house after six years!