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Residential ventilation

Energy efficient FTX-solution

Envistar Home Concept is a range of centrally located, highly efficient FTX units tailored specifically for blocks of flats. Customised control equipment and a wide range of fans, motors and heat recovery units provide everything you need for energy optimised air handling.

Simple ownership

Do you need to improve the ventilation in your property or are you constructing a new build? In which case, we would recommend the Envistar Home Concept unit, tailored specifically for blocks of flats.

The central location of the unit facilitates service and supervision. It reduces your costs and you do not need to disturb any tenants to carry out servicing.


High efficiency means that the heat recovery must be above 80%, dry temperature efficiency. In addition, the fans that drive the unit have a very low SFPv value.


  • Centrally located
  • Customised control equipment for blocks of flats
  • High degree of heat recovery
  • Components with low pressure drop
  • Efficient fans, low SFPv value
  • Each unit manages 6–160 flats
  • Easy for the property owner, the installer and the tenant

F-systems, extract air ventilation system without heat recovery


Fresh air is brought in via trickle vents in window frames. Extract air is extracted through valves in bathrooms and kitchens. The heat in this system is not recovered but disappears straight out through an extract air fan.


  • Simple duct system


  • No energy recovery means a lot of energy is wasted
  • Complicated access for filter replacement and cleaning of trickle vents
  • Cold and draughty
  • Does not meet the requirements from the Swedish National Board of Housing, Building and Planning for renovations and new-builds

Extract air unit with recovery via external heat pump


Fresh air is brought in via slot valves in window frames. Extract air is extracted through valves in bathrooms and kitchens. The heat in this system is recovered through an external heat pump, which is connected to the extract air unit via a brine system.


  • Simple duct system
  • Heat recovery from the extract air


  • Two heat exchangers result in inferior efficiency. Extract air to brine and brine to heat pump
  • Brine systems that use cold liquids give rise to exhaust air and corrosion problems and must be insulated in order to prevent condensation
  • Many separate control systems must be coordinated

Older, centrally located FTX unit with coil heat exchanger, plate heat exchanger or heat pipe



  • Easy access for replacement of filters and servicing. For example, 30 apartments = one unit, which means two fans and two filters
  • Central control and monitoring
  • Separate air paths, no risk of air transfer between extract air and supply air


  • Low-efficiency fans, usually belt driven with high maintenance costs
  • Low heat recovery rate, 40–55%

Apartment unit, FTX with heat recovery



  • Heat recovery


  • Many units give high maintenance costs. For example, 30 apartments = 30 units, which means 60 fans and 60 filters
  • Complicated access for replacement of filters
  • Risk of high noise levels
  • Installation more expensive than for a central unit