It is possible that the voltage reaching your house is low. That may require an electrician to verify, although your power company should be willing to perform at least some initial testing at no (or limited) cost.
A higher-quality PSU may compensate for this. You want one with full range active PFC (will have NO little voltage switch). A quality modern PSU also has some level of 80+ certification for efficiency. Seasonic, Antec, Corsair, XFX, and Enermax/LEPA are among the better brands.