Ventilation with heat recovery is the most energy-efficient type of ventilation, as it uses the heat or cold energy of the exhaust air to heat or cool the supply air.

• Maintenance requirements must already be taken into account during the design phase to ensure that parts of the ventilation system can be easily accessed for inspection or cleaning.
• It is not desirable to install the fresh air supply ducts and the indoor air exhaust ducts located outside the building close to each other to prevent the ventilation equipment from supplying the air that has just escaped from the house back into the building.

• By lowering the temperature of the supply air, less energy will be needed to heat the air.

• No matter how well the ventilation system works, regular checks by a specialist are required every year to ensure the longevity of the system. The technician can identify problems, for instance, the degree of wear of the parts.
• Air filters need to be changed and cleaned regularly to ensure that the ventilation equipment works efficiently and safely. Maintenance frequencies for most appliances differ according to the manufacturer. It is also affected by the intensity of the load on the ventilation unit, outdoor air pollution and the geographical location of the building.
• Cleaning the grilles, especially those in the kitchen, is essential to ensure air flow. The primary causes of airflow blockage are accumulated dust and a greasy ventilation grille.

• It is important to choose the volume of an electrical volume water heater or boiler depending on the needs of each family. Water heaters of larger volume consume more electricity. Meanwhile, if family members use water at different times of the day, a smaller boiler can also be used.
• When thinking about buying a water heater, you should examine the information provided in the energy label. Not only does it give you the energy efficiency class, estimated electricity consumption and noise level but it also helps you compare different appliances.

Recommended water heater capacity depending on the number of people in the household:

• 1 person → 30–70 litres
• 2 people → 80–150 litres
• 4 people → 100–250 litres
• 5 or more people → up to 300 litres

Depending on the space available in the room, both vertical and horizontal water heaters are available; however – vertical water heaters are easier to maintain.

It is preferable to place the volume water heater as close to the point of use as possible to prevent the heated water from cooling in the pipes.

• The temperature of the water that needs to be heated should be set between 55–59 ˚C to avoid calcification of the heating element, as well as an increase in water heating time and electricity consumption.
• If you are away from home for a long time, it is advisable to disconnect the appliance from the power supply before you leave.
• If the water heater is located in a summer house, it can be switched on remotely exactly at the time you need it by using a smart socket.
• If you do not use your water heater for a long time and turn it on again, you should first drain the water as it may contain unwanted bacteria.

• It is preferable to entrust the maintenance of the water heater to a specialist and to perform it no less frequently than once per year.
• Before cleaning, the volume water heater must be disconnected from the electricity and water supply.

Instantaneous heaters mostly require a three-phase connection and high permissible loads. Prior to buying a heater of this type, it is important to check whether it can be connected to the existing electricity grid.

There are three important criteria to consider when buying an instantaneous water heater:

1. Number of water consumption points,
2. The total possible water flow rate,
3. Technical possibilities of electricity supply.

• A 7–10 kW instantaneous water heater will allow you to shower comfortably, but for larger consumption, a heater of more than 18 kW is preferable.
• It is recommended to place the instantaneous water heater as close to the point of use as possible. However, if the living area is large and the distance between the water outlets is long, the installation of two separate instantaneous heaters may prove to be more optimal.

• Since an instantaneous water heater is more efficient than a boiler, you may need to rethink your water consumption habits to be able to reduce consumption, for instance, by using less hot water.
• Remember not to waste water unnecessarily and to reduce the water flow rate if possible.

• As with all appliances, it is best to entrust the service of your equipment to a professional, as well as to consult the user manual.
• Many water heater models have a water filter to protect against hard water, limescale and sediment. This filter needs to be cleaned. If the appliance doesn’t have a water filter, it is sometimes possible to install one, in order to improve water quality and protect the appliance.
• It is recommended to wipe the outside of the container to ensure that no dust or debris accumulate on it. Power supply must be switched off before doing so.

• Combined boilers are most often chosen for apartments or small houses, where the amount of hot water that is needed simultaneously is small.
• This solution heats water in a flow-through mode and its biggest advantage is maximum efficiency of gas consumption. This will consume less gas than a solution with a boiler connection, as the boiler heats the hot water at the moment when the hot water tap is opened.
• The energy label is awarded to combined boilers that are designed for the heating of premises and hot water preparation. The energy label indicates two energy efficiency classes: one indicates how efficiently the appliance heats the space, the other – how energy efficient it is when heating water. The energy label can also be used as a guide when comparing appliances.

• It is not advisable to consume water in several places at the same time, for instance, to take a shower when someone is already taking a bath, as the hot water temperature will drop at all points of use.
• Combined boilers should be located as close as possible to the hot water points and, preferably, no more than 10 m away.

• Regular maintenance will help to detect problems early, avoiding costly repairs or even replacing the boiler. Maintenance is also necessary from a safety point of view. Like any gas appliance, a boiler can be dangerous if problems are not properly addressed.

A regularly serviced heat pump uses 10–25% less electricity than a neglected unit.

• Outdoor units of the heat pump must not be covered.
• Check regularly for accumulations of autumn leaves or snow on it. This also applies to the bottom and side of the heat pump.
• During the winter months, take care to ensure that excessive ice or snow doesn’t accumulate on and around the equipment. This is particularly important in adverse weather conditions.
• Sharp knives or tools must not be used to remove ice or dirt from the heat pump coils. This can cause serious damage to the equipment and physical injury. If the appliance becomes frosty again, a specialist should be contacted.
• System maintenance should be carried out according to the manufacturer’s instructions, and the filters should be cleaned monthly or as required.
• A professional technician should service your heat pump once per year.

• To ensure safe and efficient operation, a gas boiler must be serviced regularly – at least once per year. Maintenance of gas boilers must be performed by a certified specialist.
• Even a few millimetres of soot and a poorly adjusted burner consume 5–10% more in terms of energy. Similarly, gas consumption increases if a component of the heating system, such as a pump, filter or valve, doesn’t work as planned. Maintenance is mandatory after the first year of operation.