The article presents a concrete example of a real operational problem with the use of so-called double-walled hot water heaters resulting from the heat-technical properties of such water heaters.

The parameters and characteristics obtained from the laboratory test are used to compare products in terms of performance and efficiency. The results also serve for the correct design and evaluation of the year-round behavior of the element built into the entire thermal system.

The article deals with the definition of consumer and basic heating rate. It is recommended to use the ratio of 50 % basic nad 50 % consumer rate or 60 % consumer and 40 % basic if individual heat meters are used.

For individual payment calculation for hot water we need an invoice from heat supplier with the total cost of the property in CZK and with the amount of GJ. In addition, we need the water supplier invoice, which includes the total cost of water and sewerage. For the calculation then we need water consumption from water meters.

Paper presents the analysis of water heating by a heat pump and influence of tank size, temperature setting and heat pump selection on annual use of electric energy.

The article deals with the issue of safety valves installation for water heaters. Neglecting of the installation conditions often causes damage to the installed appliance, or (as shown in the paper) loss on the water and sewer charges in the case of a safety valve installed in the water heater safety group.

The article summarizes overview of ways to secure water heaters in Europe, which became the basis for design of integrated methodology applied in the Czech Republic.

Sulfate attack is one of the major threats for durability of concrete in sewage collection systems where concrete sewer pipes are exposed to sulfates from waste water as well as from biogenic activity of bacteria. Damage due to sulfate interaction can result in the cracking and softening with loss of strength of concrete and it may lead to the concrete desintegration. Gypsum is the primary product of sulfate attack on concrete, after which ettringite is subsequently formed. Ettringite and gypsum are considerably larger in volume than the initial compounds, which leads to increased pressure within the concrete structure. This paper is focused on the sulfate attack on fine-grained concrete where the effect of 12 months contact of 0.5% sulfuric acid, simulating biogenic sulfuric acid corrosion, 5% sodium sulfate solution and solution simulating sewage water on various types of concrete has been investigated. The concrete specimens were characterized after exposition to the corroding media by their mechanical parameters, changes in pH and content of sulfates. It was found that after one-year exposure to sulfuric acid solution, the compressive strengths of all types of concrete significantly decreased. Sodium sulfate solution and the artificial waste water did not represent the significant corrosion environments for the concretes in terms of their strength reduction, increasing of sulfate ions content and the reduction in the pH of their aqueous leaches. The fine-grained concretes containing metakaolin and ground limestone showed the highest coefficient of corrosion resistance for the applied corrosive solutions.

The article deals in detail with the solar water heater from the EU Commission Regulation 812/2013. It describes what information provides the label and how it originated classification in the relevant energy efficiency class water heating.

The paper gives a simple method for calculating the annual production of condensate in the condensing boiler.

This article summarizes the basic concepts of Commission Regulation EU 811/2013 and 812/2013, focusing on solar equipment, solar water heaters and solar packages. Describes the responsibilities of suppliers who place such products on the market.

Rainwater is largely perceived as a waste water in Slovakia and in the Czech Republic, which should be divert as soon as possible to the sewage system. For many years it was mostly only one way of drainage of buildings and paved surfaces generally called “conventional way” of drainage. This paper describes the possibility of using rainwater in the school building, on the basis of the measured volume of rainwater runoff draining from the roof construction. The data were compared with the theoretical values of the water needs for the building.

This paper describes measured data and evaluation of water consumption in a family house, where secondary source of water was introduced - water from a well. Potable water was fully replaced by well water for the purpose of flushing toilets and laundry . This paper also describes the measurement data of stormwater runoff from the roof of the school building as a potential alternative water source for this building. Next step was the comparison of the current potable water consumption in the building with inflowed rainwater and evaluation of its potential for supplying the object in case of accumulation of this water.

Apartment buildings often deal with the question whether it is preferable to install gas boiler in every apartment or to build boiler room and transport heat to apartments. The article proposes a procedure to obtain information for decision.

Paper shows the results of laboratory testing of heat exchanger and its application in real operation in household. Although the efficiency of shower heat exchanger reaches even above 40 %, achieved energy savings for hot water preparation range between 10 and 15 %.

The introduction of stricter Ecodesign requirements for products associated with the consumption and production of energy is related to a smooth transition to the use of gas condensing boilers. In practice, exchanges of old boilers meet incorrect interpretation and perceptions about the benefits of condensing boilers. The article therefore assesses the impact of condensation theory and measurement and answers some practical issues.

There are a number of hydrogeological sites unsuitable for construction - there is nowhere to drain and building in the inappropriate area creates barriers to drain rainwater from the site. Then, the only solution is to minimize runoff.

The introduction of stricter Ecodesign requirements for products associated with the consumption and production of energy is related to a smooth transition to the use of gas condensing boilers. In practice, exchanges of old boilers meet incorrect interpretation and perceptions about the benefits of condensing boilers. The article therefore assesses the impact of condensation theory and measurement and answers some practical issues.

The article deals with possibilities of using heat from waste water discharged by outlet pipes of house appliances. The first section describes the basic possibilities of the local heat recovery (recuperation), used mainly in showers and shower baths. Theoretical analysis of the efficiency and related achievable savings is supported by an experimental measurement of a selected type of recuperative heat exchanger. The results of the measurement are compared with the classification according to the Passive House Institute. In addition to the efficiency and energy savings achieved by deploying the recuperative heat exchanger, the economic return of the specific heat exchanger is also determined for different boundary conditions.