Apartment-specific ventilation for new apartment block
Published 23.11.2015, edited 5.2.2024
Apartment-specific ventilation makes living more comfortable
As they say, a sign of good ventilation is that you don’t notice it. For ventilation to function smoothly, it must conform to very different needs. The number of persons in similar apartments may vary a lot. One-person households get by with considerably lower-scale ventilation than larger families. A variation is also caused by the hours of the day. Older people may be very sensitive to draughts. On the other hand, modern and efficiently insulated apartment blocks often have problems with overheating. In a very warm apartment, the indoor air quality is experienced as being poor. Many blame the ventilation, while the actual reason may be a too high temperature indoors. It is, therefore, important that the residents can influence the efficiency of the ventilation.
The removal of humidity is the most important function of ventilation. Wet rooms must be dried quickly after use, so that the structures stay in good condition and the home is kept fresh. However, it is not sensible – and not comfortable either – to have such efficient ventilation on all of the time. Room-specific ventilation can be boosted when the need arises. A humidity sensor connected to the ventilation unit does this automatically, and boosting is never left on when it is not needed.
Indoor air can feel too dry in winter but, on the other hand, the drying of large loads of laundry requires the efficient removal of humidity. When there is no one at home, it is possible and recommendable to reduce the ventilation to save energy. When residents can adjust the ventilation according to their needs, their satisfaction increases. Moreover, the housing company can achieve considerable savings in heating energy and electricity consumption by using apartment-specific and needs-based ventilation adjustments.
An apartment-specific ventilation system is simple and reliable
Apartment-specific ventilation units are factory-made ready-for-service units that include the desired automatic functions as well as connections to other building technology solutions.
In a building equipped with apartment-specific ventilation units, the ventilation does not change when outdoor temperatures vary, which can happen with centralised ventilation systems covering an entire house or the apartments served by the same staircase. When there is no duct connection between apartments, there is no “chimney effect” that often appears in apartment blocks: the apartments on the upper floors suffer from overpressure generated through the ventilation ducts, while extract ventilation on the lower floors increases, causing increasing underpressure, air infiltration from the structures and draught.
Moreover, decentralised ventilation has other advantages that increase the comfort of living: sounds, smells or possible combustion gases cannot migrate between apartments through ventilation. A decentralised ventilation system is fireproof, as all of the ducts and parts are located in an individual apartment. The ducts do not need dampers that require maintenance or monitoring; it is not always easy to notice that dampers have gone faulty.
Ventilation units equipped with a plate heat exchanger do not mix clean and dirty air and do not return the smells or humidity of extract air in supply air into the apartment. The plate heat exchanger does not contain any moving, wearing or breaking parts and does not require any other maintenance than cleaning.
An apartment-specific ventilation system is basically simple, easy to adjust and quick to take in use. The speed of the DC fans can be adjusted steplessly, and the supply and extract air ratio can be adjusted independently. The system can be taken in use in one apartment at a time as the ventilation installations progress; there is no need to wait for all the apartments to be complete.
Thanks to the ingenious Vallox defrosting automatics, defrosting cycles do not create additional underpressure in the apartments on cold winter days. The heat recovery cell is defrosted in the most economical way: with the heat energy of extract air. No electrical resistor is used for keeping the cell defrosted. Instead, the heating energy of the house is used for this purpose, whether it comes from district heating, geothermal heating or overheat. Both fans are always on, and at the moment of defrosting, supply air comes in past the heat recovery cell. The post-heating resistor takes care of the heating supply air, so the defrosting periods are not noticeable. As the amount of energy consumed for post-heating is low, post-heating can always be implemented with an electric resistor, which further increases reliability.
The constant flow feature keeps the air pressure at a constant level
A ventilation unit equipped with constant flow fans ensures that the air pressure in the apartment remains at a constant level. A unit with a CF fan compensates for the change in pressure differences caused by dirty filters and valves, fluctuating outdoor temperatures, the formation of ice and condensing water on the heat recovery cell, heat recovery bypass, etc.
The constant flow feature is particularly useful in apartment blocks, as it can be used for compensation of the wind effect. It prevents problems caused by variations in air pressure, such as the misting of windows caused by overpressure and the accumulation of heat on the upper floors. Equipped with constant flow fans, the Vallox 99 MV CF ventilation unit is an excellent choice for apartment-specific ventilation in apartment blocks.
Apartment-specific ventilation is economical
The costs of purchasing a ventilation system depend not only on the unit and duct system but also the associated building work. Auxiliary work can account for a significant share of the starting costs of ventilation. Apartment-specific ventilation is economical to implement as there is no need for a machine room and large duct grooves.
An independent cooker fan usually removes cooking smells better than a cooker hood connected to the ventilation unit. However, cooker hoods are normally used in apartment blocks, so that a specific extract duct from the cooker to the roof is not needed. If cooking smell removal by the cooker hood is connected to the ventilation unit, the extract air from the cooker hood must also pass through the heat recovery cell, so that the cell stays defrosted even in cold winter weather and ventilation works properly.
Inside the apartment, there are usually only a few ventilation ducts. Most of the ducts are installed in the ceiling of the bathroom and the entrance area. Other rooms may only have a ventilation valve on the wall.