In terms of condition and performance, it is extremely important to maintain ventilation units at regular intervals. Maintenance interval varies by location. If the unit is in town, built-up area or by an active traffic area, the basic maintenance should be done twice a year. In rural areas one year service interval is usually sufficient.

In basic maintenance, the ventilation unit filters are replaced, the heat recovery cell is cleaned and the inside of the unit is vacuumed. The above-mentioned measures are carried out in accordance with the unit manufacturer's instructions. The following is a small checklist for maintenance:

  1. Turn off the ventilation unit to prevent the filter dust from spreading into theducts and around the room facilities. Take the ventilation unit’s fuse off to avoid electric shock.
  2. Open the ventilation unit. (Read the manufacturer's maintenance instructions)
  3. Remove the old filters. It is convenient to put the old filters into the box that came with the new ones. After the service you can dispose of the box with regular household trash.
  4. If the device is equipped with a removable heat recovery cell, remove and wash / vacuum the device according to the manufacturer's instructions. This ensures the heat recovery cell’s  100% operational activity and you will save money on post-heating costs. (Read the manufacturer's maintenance instructions)
  5. Vacuum or wipe carefully the interior of the device. (read the manufacturer's maintenance instructions)
  6. Set the heat recovery cell in place.
  7. Insert the new filter into place.
  8. Close the unit.
  9. Turn on the fuses and the unit.

If the checklist seems too challenging, the local service companies will perform maintenance in no time.


What are the consequences if the ventilation unit is not maintained periodically?

Replacement of the filters as well as cleaning the inside of the device is a very important part when fresh and clean air flow is expected. Failing to follow these measures will without a doubt pollute the indoor air, whether it's old or new dwelling.Service life of a filter is usually six months to one year. Within this time the dust load ofthe filter become full, and the technical characteristics of the filter starts to deteriorate. The indication of deterioration is, among others, the pressure difference which is higher thaninitial values ​​(clean filter), which significantly reduces the amount of fresh air flowing in to the building. In addition to theincrease in pressure difference, dust, accumulated in the filter, form an excellent breeding ground for mould. Along with the heat and humid air and the dust, several years old filters without replacement becomea risk to health.

Air quality-related harmful effect in addition to maintenance neglect is also reflected in the energy consumed by the ventilation unit. Heat generated from exhaust air is recovered by heat recovery cell in almost all ventilation systems. As in Finnish, the heat from the exhaust air is transferred through the cell to the supply air. If the annual maintenance is neglected, the airborne dust particles are accumulated in the heat recovery cell surface.

This dust prevents and weakens the heat transfer into the supply air, and thus reduced the cell's ability to recover heat. This phenomenon of losing ability to recover heat is compensated by post-heating radiator, which means that the unit has to heat the air, for example electrically or with a water heater. Annually this additional heating costs, at worst, many times the price of a single filter.Given the above information, it is easy to see that a few tens of euro’s is a small price to pay compared to the health risk caused by mould.