A sign of
good ventilation is that you don't notice it. A ventilation system that
operates unnoticeably requires careful design, which involves paying attention
to the characteristics of the building, the users and the purpose of use. Good
ventilation is silent, consumes a small amount of energy and keeps indoor air
fresh in all situations.
1. Hire a
house is a strictly regulated process. According to the land use and building
acts, if you start a building project, you have to take care of designing and
constructing the building in accordance with the building permission and the
related rules and regulations. A builder needs sufficient qualifications and
competent people to implement the project. Because of this, you have to hire a
principal designer who is responsible of the ventilation system of the house,
old house is renovated, the role of design is even more significant, for
ventilation needs to be an unnoticeable part of the old building.
it is good if every house builder and renovator himself knows the many factors
that have to be taken into account when ventilation is installed. The Finnish
society of indoor air quality and climate (www.sisäilmayhdistys.fi) recommends
that you write down the indoor air quality objectives in design documents by
consulting manuals such as
Classification of Indoor Environment 2008,
2. Correctly sized
choose a ventilation unit, it is essential to choose the size of the unit to
match the needs. In normal circumstances, the ventilation unit must be able to
change the calculated air volume once every two hours at about half power. This
ensures that ventilation can be boosted if needed. In order to save energy it
is also good if ventilation can be easily reduced when the dwelling is empty.
It has to
be remembered, however, that dimensioning based on air volume is not always
correct. The number of persons and functions also have an effect on the
therefore important to use the number of persons as the primary starting point
for the dimensioning of the outdoor air flow.
functions of the unit
sensible to adjust ventilation as needed in order to have the system consume as
little energy as possible. If ventilation operates all the time at the same
power, it is sometimes insufficient and sometimes too high. There are many
options for controlling ventilation, from manual adjustment to fully automatic
ventilation. Humidity and carbon dioxide sensors enable an intelligent
home/away/boost automation: the amount of ventilation is adjusted depending on
air quality, or the current humidity and carbon dioxide load.
4. Heat recovery
capacity of the unit
important characteristic of a ventilation unit is its heat recovery capacity.
It refers to the capacity of the unit to heat the air coming in with the heat
from the air extracted. This means that less energy is required for the heating
of cold outdoor air.
measure of the heat recovery capacity is annual efficiency. Annual efficiency
has a large impact on the primary energy indicator and the actual energy
consumption. You can calculate the annual efficiency of the ventilation unit by
using the annual efficiency calculator provided by the manufacturer.
5. Location of the
ventilation unit has to be located indoors, in a warm room with a temperature
of at least +10 °C. The location of the
ventilation unit is good when its sound does not disturb and its maintenance is
easy. It is not nice to replace dirty filters in a walk-in closet, for
instance. Moreover, as efficient heat recovery cells are big, a considerable
space is needed for detaching them for cleaning.
technical room, a warm storage or a utility room are good locations. Because of
disturbing sounds, the unit must not be fixed on a wall next to a bedroom or
living area. When choosing a location, you should also pay attention to the
fact that the unit has many electrical connections, and also condensing water
has to be drained.
recommended to build the ventilation ductwork as short as possible; a long and
complicated ductwork is expensive and backfires as far as SFP and sound level
are concerned. It is good if the ductwork can be installed in warm rooms
indoors. Suspensions, intermediate floors, enclosures and partitions provide
good routes for ventilation ducts. If all ducts are inside the vapour barrier,
there is no need to insulate them thermally, nor are there any unnecessary
holes in the vapour barrier.
living comfort, it is also important to pay attention to attenuating the sound
of the ductwork. Even if a sound level meets the regulated level, it can be
disturbing in a bedroom, for instance. It pays to implement the sound
attenuation of the ductwork with silencers located in the ductwork. In some
unit types, sound attenuation can be implemented with a silencer part in the
unit combined with duct silencers if needed. In addition, it is wise to make
sure that the sound cannot travel in the structures from the technical room to
bedrooms, for instance.
location for the outdoor air duct
air grille located on a wall or below the eaves must be located on the cooler
side of the house so that the sun will not heat the air coming in too much in
summer. Furthermore, supply air should not be taken indoors in a place which is
close to a dusty street. Exhaust air is led to the roof or from the wall to the
outside if the local building supervision allows it.
8. Air circulation
For air to
circulate in the whole dwelling, suitable circulation routes are needed. One
way to ensure this is to have no doorsteps under doors. Alternatively, you can
insert ventilation openings in doors or walls. Mechanical supply/extract air
ventilation does not prevent you from having windows open or airing through
windows. When ventilation has been planned properly, there is no need for
window ventilation, for the unit brings clean filtered air into the living
rooms. The best air quality in the living areas is ensured by leading supply
air to the cleanest rooms, such as bedrooms in dwellings. From there it flows
to the kitchen and the wet rooms and goes back to the outside through the
discharge openings located in the rooms last mentioned.
9. Taking into use
ventilation system is bought, it is always necessary to agree with the supplier
upon the adjustments for the system. Proper implementation of ventilation also
involves guidance and information of the operating speed of the unit in order
to ensure sufficient ventilation in different situations.
cleanliness of the ventilation unit at an interval of 3 to 6 months. If needed,
clean or replace the filters and remove other litter and dirt. In the course of
time, you will learn to know the maintenance interval required by the unit, but
many models also have a maintenance reminder. The filters should be replaced/cleaned
in spring and autumn, but you have to replace them at least once a year. The
need for maintenance depends on the residential environment.