A counterflow heat exchanger configured to exchange thermal energy between a first fluid flow at a first pressure and a second fluid flow at a second pressure less than the first pressure includes a first fluid inlet, a first fluid outlet fluidly coupled to the first fluid inlet via a core section, a second fluid inlet, and a second fluid outlet fluidly coupled to the second fluid inlet via the core section. A heating arrangement is configured to heat the second fluid inlet to prevent ice ingestion via the second fluid inlet.