Experience report bluMartin freeAir100
For all builders who are dealing with the topic of ventilation systems, our experiences with the ventilation system bluMartin freeAir100. House: built in 2015, timber frame construction, 175 sqm, 2 floors, pellet heating, solar system, photovoltaic system, decentralized ventilation system bluMartin freeAir100 (3 main units each with one secondary room connection), KFW 55. We decided on bluMartin freeAir100 because, in our opinion, it combines the advantages of a central and a decentralized system and due to the passive house certification. Result: It is worth mentioning positively that the system is able to dehumidify the rooms. Especially in the laundry room, all the moisture generated from drying laundry is expelled outside. According to the manufacturer's analysis software, the heat recovery is also high. The air quality is not sufficient. Without open windows, we perceive the air in closed rooms as stale after a few hours. Extensive measurements (device: CO2 monitor by Dostmann) showed that the CO2 concentration in the morning was between 1500 ppm and partly over 2000 ppm. There are no legal requirements for private houses. Recommendations (e.g. Pettenkofer value of 1000 ppm) are, however, exceeded. As a result, we have to tilt the windows in the bedrooms and regularly open windows in other rooms for ventilation. The units are audible even at the lowest level. For sleeping, they are too loud for us in the rooms with main units. In the rooms with secondary connection, the ventilation is barely audible at the lowest setting. The longer the filter is in use, the louder the noise develops. I also switch off the system when reading. The filters must be changed at least once a year or when the maintenance indicator appears. In our case, the error message "Filter Error" always appears well before one year has passed. The required set is only available via Amazon and costs us 96 euros for three units in total (as of 10/2019). Meanwhile, the manufacturer has fortunately dispensed with the aluminum frame, which improves the ecological balance. After four years of use, all three units had to be sent to the manufacturer for repair work. The customer receives shipping cartons for this purpose. For two devices, the error message "Filter Error" did not disappear even after filter replacement. The third device switched off by itself. (When trying to turn it on again, I received an electric shock on the main switch, which is made of metal! The main circuit board had to be replaced.) The repair costs, despite generous discounts, were more than 500 euros. Conclusion: If faced with the decision again, we would either choose a central ventilation system or dispense with it entirely, even though we are aware of the problem of ventilation in airtight construction. The costs for the system in the amount of 12,000 euros net (2015) could, for example, be invested in other energy-saving or energy-generating measures. We would not choose the product bluMartin freeAir100 again.
Best regards Dietmar