At LHC energies, the high amount of energy available in the c.m.s enables the production of W bosons with fairly large yields. Their production will permit to probe PDFs at low Bjorken-x range, $x \sim (10^{-4}-10^{-3})$ for $Q2 \sim m_{W}^{2}$, and to study nuclear modification of quark distribution functions. Furthermore, as electroweak probes produced in initial hard collisions, they will allow to check Glauber model scaling and they could serve as a reference tool for observing medium induced effects on other probes, like energy loss of high $p_T$ b-quarks. W production at LHC and its detection in the ALICE muon spectrometer will be presented for p+p, Pb+Pb, p+Pb and Pb+p collisions. Muon charge asymmetry and muon yield ratio for different $p_T$ bins will be discussed as single muon observables for W production and for studies of heavy quarks energy loss, respectively.