Comment on "Heat-Flow Induced Anomalies in Superfluid 4He near Tλ"

In a recent Letter [1], Haussmann and Dohm (HD) presented a renormalization group treatment of the 4He lambda transition in a heat current Q. In this Comment, we use simple arguments that yield the same critical point exponent for the depressed Tl, and nearly the same critical velocity, but indicate that HD may not have calculated the proper specific heat anomaly.