"Må" is a rather unique verb that is only used to mean "to feel" in the context of a person's (or animate object's) mood, health, etc. For example, the phrase "Hur mår du?" ("How are you feeling?") is inquiring about the physical and/or mental state of the respondent. For all other purposes where you would use the English verb "to feel", you would use "känna" in Swedish. You can therefore say "Huset känns tomt" ("The house feels empty"), but you cannot say "Huset mår tomt".