Avtrekksvarme

Avtrekksvarme refers to the heat energy contained in the air that is exhausted from a building through its ventilation system. In systems with energy recovery, the outgoing warm air passes through a heat exchanger where its heat is transferred to the incoming outdoor air, preheating it before it enters living spaces. This process reduces the heating demand and is a central feature of ventilation systems with heat recovery (MVHR).

Technologies used to recover avtrekksvarme include plate heat exchangers and rotary heat exchangers (enthalpy wheels), as well as heat pipes. Some systems also recover latent heat, meaning moisture from the exhaust air is transferred to the incoming air to help maintain indoor humidity. The choice of technology affects efficiency, maintenance requirements, and the extent of humidity control.

Avtrekksvarme is widely used in residential and commercial buildings in climates with cold winters, where it can significantly reduce energy consumption and CO2 emissions while improving indoor comfort. By maintaining more stable indoor temperatures and providing continuous ventilation without increasing heating load, it supports better overall energy performance.

Efficiency and performance depend on factors such as outdoor temperature, indoor-outdoor temperature difference, and the building’s airtightness. Typical sensible heat recovery efficiencies range widely by system and conditions, and latent heat recovery can enhance humidity control. Maintenance is important to prevent reduced performance, odors, or mold, including filter cleaning and ensuring there is no unintended bypass.

Design considerations include proper sizing of the MVHR unit, minimizing pressure drops, and ensuring good filtration. Avtrekksvarme is a key component of energy-efficient building ventilation and is often part of broader strategies for sustainable heating and air quality.