  We present an overview on how variability can be used to constrain the
location of the ionized outflow in nearby Active Galactic Nuclei using
high-resolution X-ray spectroscopy. Without these constraints on the location
of the outflow, the kinetic luminosity and mass loss rate can not be
determined. We focus on the Seyfert 1 galaxy NGC 5548, which is arguably the
best studied AGN on a timescale of 10 years. Our results show that frequent
observations combined with long term monitoring, such as with the \textit{Rossi
X-ray Timing Explorer (RXTE)} satellite, are crucial to investigate the effects
of these outflows on their surroundings.
