diff --git a/surfinpy/chemical_potential_plot.py b/surfinpy/chemical_potential_plot.py
index bca4d53..d1355cc 100644
--- a/surfinpy/chemical_potential_plot.py
+++ b/surfinpy/chemical_potential_plot.py
@@ -31,26 +31,31 @@ def __init__(self, x, y, z, labels, ticks, xlabel, ylabel):
         self.xlabel = xlabel
         self.ylabel = ylabel
 
-    def plot_phase(self, temperature=None, xlabel=None, ylabel=None, output="phase.png", colourmap="viridis",
-                   set_style="default", figsize=None):
+    def plot_phase(self, temperature=None, xlabel=None, ylabel=None, output="phase.png", 
+                   colourmap="viridis", set_style="default", figsize=None, show_fig=True):
         """Plots a simple phase diagram as a function of chemical potential.
 
         Parameters
         ----------
-        temperature : int (optional)
+        temperature: int (optional)
             Temperature. Default=None
         xlabel: str (optional)
             Set a custom x-axis label. Default=None
         ylabel: str (optional)
             Set a custom y-axis label. Default=None
-        output : str (optional)
+        output: str (optional)
             Output filename. Default='phase.png'
-        colourmap : str (optional)
+            If output is set to `None`, no output is generated.
+        colourmap: str (optional)
             Colourmap for the plot. Default='viridis'
-        figsize : tuple (optional)
+        figsize: tuple (optional)
             Set a custom figure size. Default=None
+        show_fig: bool (optional)
+            Automatically display a figure. Default=True
+            If set to False the plot is returned as an object.
         """
-        plt.style.use(set_style)
+        if set_style:
+            plt.style.use(set_style)
         levels = ut.get_levels(self.z)
         ticky = ut.get_ticks(self.ticks)
         temperature_label = str(temperature) + " K"
@@ -75,8 +80,12 @@ def plot_phase(self, temperature=None, xlabel=None, ylabel=None, output="phase.p
         cbar = fig.colorbar(CM, ticks=ticky, pad=0.1)
         cbar.ax.set_yticklabels(self.labels)
         plt.tight_layout()
-        plt.savefig(output, dpi=600)
-        plt.show()
+        if output:
+            plt.savefig(output, dpi=600)
+        if show_fig:
+            plt.show()
+        else:
+            return ax
 
     def plot_mu_p(self, temperature, output="phase.png", colourmap="viridis",
                   set_style="default"):
@@ -92,7 +101,8 @@ def plot_mu_p(self, temperature, output="phase.png", colourmap="viridis",
         colourmap : str
             colourmap for the plot
         """
-        plt.style.use(set_style)
+        if set_style:
+            plt.style.use(set_style)
         p1 = ut.pressure(self.x, temperature)
         p2 = ut.pressure(self.y, temperature)
         temperature_label = str(temperature) + " K"
@@ -140,7 +150,8 @@ def plot_pressure(self, temperature, output="phase.png", colourmap="viridis",
         colourmap : str
             colourmap for the plot
         """
-        plt.style.use(set_style)
+        if set_style:
+            plt.style.use(set_style)
         p1 = ut.pressure(self.x, temperature)
         p2 = ut.pressure(self.y, temperature)
         temperature_label = str(temperature) + " K"
diff --git a/surfinpy/pvt_plot.py b/surfinpy/pvt_plot.py
index 98bba67..c5463ac 100644
--- a/surfinpy/pvt_plot.py
+++ b/surfinpy/pvt_plot.py
@@ -30,7 +30,8 @@ def plot(self, output="Phase.png", colourmap="RdBu", set_style="ggplot",
         atmospheric_conditions : list
             location of bars showing atmospheric conditions
         """
-        plt.style.use(set_style)
+        if set_style:
+            plt.style.use(set_style)
         fig = plt.figure()
         ax = fig.add_subplot(111)
         ax.contourf(self.x, self.y, self.z, cmap=colourmap)