The planning of ventilation affects the energy-efficiency and indoor air quality of
your home. Before building or renovating ventilation in the home, the first step is
to hire a HVAC designer.
When preparing the ventilation plan, the designer observes the requirements related to the indoor
air and ventilation of the building. For instance, the plan describes the airflows in the apartment, the
implementation of soundproofing and the type of a suitable ventilation unit. The designer also specifies
the efficiency of ventilation for various circumstances in the home. Builders of their own homes
and those renovating ventilation are advised to contact an HVAC designer to discuss the automation
and control options to find the best ventilation solution to suit their needs and preferences.
Mechanical ventilation promotes energy-efficiency
The airtightness of the building affects energy-efficiency, which is why controlled ventilation plays a major role. The energy consumption of mechanical ventilation is affected by two factors:
- Heating of the air that replaces the air being extracted. The more efficient the heat recovery, the less energy the postheating radiator consumes.
- With the current EC motors, the electricity consumption of the fans is quite low.
Heat recovery can generate savings in other heating of the house, as the ventilation unit can use the heat in the extract air. When choosing a ventilation unit, the annual efficiency is the most important figure indicating energy consumption. It indicates how much of the heat in the extract air the unit’s heat recovery system can utilise on average throughout the year. The figure takes into account important
practical questions, such as the operation of freeze protection and the weather conditions. Therefore, the annual efficiency figure is always lower than the temperature efficiency figure, and this should be kept in mind when comparing the efficiency of units. For instance, in larger detached houses, the annual efficiency of a typical MyVallox 149 CFi ventilation unit is as high as 83%!
Recover heat, don’t waste it
The heat recovery cell plays an essential role in mechanical ventilation. It utilises the heat recovered from the extract air and transfers it into the supply air. This way, the supply air is also suitably warm in cold weather, in addition to which the system reduces the heating need of the house. Even on cold days, the ventilation unit can heat the supply air to +17 degrees Celsius, and the heating system of the home
has to account for only a few degrees.
Smart defrosting automation
All Vallox ventilation units feature defrosting automation that is activated only when needed. The cell is defrosted with the heat in the extract air and the post-heater heats the supply air, while the electric heating is fully used for heating the home. The Vallox winter function prevents unnecessary defrosting cycles, so that a better annual efficiency is achieved.
It is wise to use ventilation according to the need
Standard ventilation is dimensioned for each room according to use. Ventilation must be boosted when
the humidity and carbon dioxide content of indoor air increase. Lower efficiency is sufficient when the apartment is left empty. Demand-based ventilation adapts to the use of the room. It is also energy-efficient: when the efficiency is halved, the energy consumption of ventilation drops by more than half. Therefore, there is no need to turn ventilation off completely for energy saving reasons but use it according to the need.
Automated MyVallox ventilation units ensure demand-based ventilation. The integrated carbon dioxide and humidity level sensors automatically boost ventilation, until the desired level is reached. This way, ventilation is never accidentally left too high.
Mechanical or natural ventilation?
Mechanical ventilation only accounts for about ten per cent of all the electricity consumed. Similarly, in houses with natural or extraction ventilation, ventilation takes up roughly 20–40% of the energy used for heating. For this reason, the energy-efficiency of the ventilation system has a significant impact on the heating costs of the building.
The calculation of the energy consumption of the household used as an example was based on a terraced
home with two residents. In this house with district heating, the average annual electricity consumption is 4,100 kW.
What should a builder know about ventilation design?
