When leaving home, it is tempting to switch ventilation off entirely because nobody will be there. However, materials, moisture and other sources remain in the building, and specific operating conditions may apply to the unit. On the other hand, leaving the highest setting on continuously is not always justified either. Choose an appropriate away mode according to the house, system and duration of absence, not one fan percentage prescribed for everyone.
An unoccupied house is not a place where all processes stop
When people leave, the load they create decreases, but not every indoor-air problem disappears. Damp materials, household pollution sources or the effects of basement conditions may remain; the EPA air-quality guide discusses different sources and their control. “Nobody is breathing there” is therefore not the only criterion for a ventilation decision.
It also matters whether you are leaving a completed, dry house or a new building after wet construction work. These are different cases. A seasonal country home, an unheated house and a continuously heated dwelling have different conditions. Experience at one property cannot automatically be transferred to another, even with a similar heat-recovery unit.
Start with the model's manual
The Komfovent user manual gives examples of particular control modes. Your unit may have an away, reduced-use or other function, but its meaning must be checked. A mode's name alone does not reveal the actual airflow or how all protective functions operate.
The installation manual also matters for environmental and operating conditions. A recommendation for one specific model cannot be generalised to every manufacturer. If the document specifies procedures for a longer shutdown, follow them. Do not use disconnection of the power supply as a general energy-saving function before understanding what it changes.
A percentage does not mean the same airflow in every house
The same controller percentage may mean a different airflow depending on the unit and system. Advice to “always leave it at this percentage” without a model and sizing assessment is therefore not precise. It is better to have a reduced-use mode established during acceptance of the property and clear instructions on when to use it.
Also check that reduced operation does not leave a separate zone without its intended air path. Closed doors, taped-over openings or altered finishes may affect the result. Away mode must not become a way to conceal an unbalanced system. First ensure that it operates correctly under normal conditions, then reduce the load on a sound basis.
Illustrative example: a two-week trip
Suppose a family leaves a continuously heated, dry house. The unit has a designated reduced-use function. The owner checks the filters according to the maintenance procedure, ensures there are no leaks or unresolved errors and selects the mode discussed with the contractor. This is not simply a random reduction of speed to the lowest possible number.
On returning, restore the mode to suit use. If there is an unusual smell or humidity indoors, assess whether the cause relates to the mode or to a separate problem. A brief intensive airing cannot replace a search for a leak. The sequence of observations and messages helps determine whether another check is needed.
A new, damp house needs a different plan
Leaving after concreting or plastering does not mean drying is complete. Moisture must be removed in a way that meets material and equipment requirements. A domestic system must not be used as unverified construction-site equipment. If work is still dusty, protection against contamination is needed too. Select away mode only after assessing the actual construction stage.
In this case, the owner needs to know who will monitor conditions and how faults will be addressed. A remote reading can help but does not replace physical assistance if water appears. Do not leave unclearly configured temporary equipment for a long period merely in the hope that an app will show everything. There must be a clear plan for safe use.
Winter and summer differences
In cold weather, the particular model's protective functions and the building temperature matter. In summer, outdoor air and humidity conditions may change. One year-round mode is therefore not necessarily justified for every season. Distinguish temperature maintenance from air exchange: reduced house heating may also change moisture conditions.
If the house is left unheated, a separate winterisation plan is needed for all building-services systems. Ventilation cannot be treated as frost protection for every pipe. Different systems have different tasks. When discussing an absence, explicitly identify what remains running and what protection is provided for each part.
Automation and notifications
If a weekly schedule or remote control is used, check what happens after a power cut. Does the previous mode return, how are notifications received and who has access? Control must remain with the owner, not an unclear contractor account. This is particularly important for longer absences.
Not every status displayed in an app proves actual airflow in all rooms. Automation helps control the system but does not replace installation and actual testing. If the system reports errors, do not disable them merely for peace of mind on your trip. Understand the cause of the message and, where necessary, resolve it before leaving the house for a longer period.
Try a new mode while still at home
If reduced mode has not been used before, do not leave its first long trial until nobody can inspect the building. Check the intended operation beforehand and understand the controller messages. This does not guarantee every future condition, but it helps reveal an incorrect setting or misunderstood function before departure.
After returning, record the observed condition and review the history if data is logged. Such records will help choose a justified mode next time. Do not conclude from one good experience that the same arrangement will suit a longer winter absence or a newly renovated, damp house. Reassess the plan when conditions change.
What to discuss with the contractor
Ask for a specific description of normal and away modes linked to the condition of the house. State the duration of absence, heating arrangements and remaining moisture sources. Read more about maintenance here, and submit your question in an enquiry. Sensible energy saving means a justified lower mode when suitable, not universally switching off the whole system without checking the conditions.
Information sources
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