This fireplace insert is intended for passive houses, which are subjected to an airtightness test- known as Blower Door test- of the house. This insert is the top among hot-water fireplace inserts for economical houses, which even though they have low claim to energy intensity, they cannot be without heat source in our winter climate conditions. The inserts Bef Aqualite 6 Passive are able to heat a house for a low price and create thermal comfort.