Based on calculations, we came to the values that were needed for taking dimensions of underfloor heating system and to the energy certificate that was nevertheless important to see how much of energy was spent in order to achieve thermal comfort.Furthermore, the popularity of pellet furnaces is increasing in the last few years because pellets can be bought in bags, filled in the tank and automatically dosed. An advantage of pellets is their efficiency: they can be made from small twigs as well as from remains of materials from wood industry. The underfloor heating system was chosen simply because the project house is a family house, where a lot of time is spent. In this way the thermal comfort was achieved in feet zone, eliminating the possibility of getting cold feet.Another important factor is the best possible isolation of the house during the winter period because otherwise the heat released in the water boiler would go throughout the walls and doors, instead of keeping the people inside warm. In that case, even more energy would have to be spent to follow up on the lost one.Because of the expensiveness of those kinds of investments, the government provides various stimuli for choosing energy efficient products and for modernisation of heating system. With the increasing number of companies oriented that way, this kind of investment will become more affordable for consumers. To conclude, another reason to use the energy efficient products is the reduction of expenses. The more outside temperature is being used, the less energy is being taken from the network, the expenses are becoming lower.