diff --git a/app/assets/javascripts/map_functions.js b/app/assets/javascripts/map_functions.js
index 4c8dcac..c71a653 100644
--- a/app/assets/javascripts/map_functions.js
+++ b/app/assets/javascripts/map_functions.js
@@ -132,5 +132,5 @@ function updateSelector(lat, lng) {
   lng = lng.toFixed(1)
   $('#latitude').val(lat)
   $('#longitude').val(lng)
-  console.log("Clicked on " + lat + "," + lng)
+  console.log(`Clicked on ${lat}, ${lng}`)
 }
diff --git a/app/controllers/weather_controller.rb b/app/controllers/weather_controller.rb
index 8fb0d5a..2cbe64d 100644
--- a/app/controllers/weather_controller.rb
+++ b/app/controllers/weather_controller.rb
@@ -36,7 +36,12 @@ def et
         data = response[:data].collect do |key, value|
           key = JSON.parse(key.to_s)
           value ||= 0.0
-          {latitude: key[0], longitude: key[1], et_mm: value, et_in: value * 25.4}
+          {
+            latitude: key[0],
+            longitude: key[1],
+            et_mm: value,
+            et_in: helpers.mm_to_in(value)
+          }
         end
         send_data(to_csv(data, headers), filename:)
       }
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 9d51b09..794f10c 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -2,18 +2,36 @@ module ApplicationHelper
   FROST_COLOR = "blue"
   FREEZE_COLOR = "#c5050c"
 
+  # unit conversions
   def c_to_f(c)
-    return if c.nil? || !(f.is_a? Numeric)
-    c * (9.0 / 5) + 32
+    c * 1.8 + 32.0
+  rescue
   end
 
   def f_to_c(f)
-    return if f.nil? || !(f.is_a? Numeric)
-    (f - 32) * (5.0 / 9)
+    (f - 32.0) * (5.0 / 9.0)
+  rescue
+  end
+
+  def in_to_mm(inches)
+    inches * 25.4
+  rescue
+  end
+
+  def mm_to_in(mm)
+    mm / 25.4
+  rescue
+  end
+
+  def mj_to_kwh(mj)
+    mj / 3.6
+  rescue
   end
 
+  # formatters
   def fmt_num(num, digits = 0)
     return num || "" unless num.is_a? Numeric
+    return 0 if num.zero?
     sprintf("%.#{digits}f", num.round(digits))
   end
 
diff --git a/app/models/unit_converter.rb b/app/models/unit_converter.rb
deleted file mode 100644
index 92661f4..0000000
--- a/app/models/unit_converter.rb
+++ /dev/null
@@ -1,5 +0,0 @@
-module UnitConverter
-  def c_to_f(c)
-    c * (9.0 / 5.0) + 32
-  end
-end
diff --git a/app/views/weather/_data_tbl_et.html.erb b/app/views/weather/_data_tbl_et.html.erb
index 5ee4c8b..c1b8efc 100644
--- a/app/views/weather/_data_tbl_et.html.erb
+++ b/app/views/weather/_data_tbl_et.html.erb
@@ -28,8 +28,8 @@
           <td><%= day[:date] %></td>
           <td><%= fmt_num(day[:value], 3) %></td>
           <td><%= fmt_num(day[:cumulative_value], 3) %></td>
-          <td><%= fmt_num(day[:value] * 2.54, 3) unless day[:value].nil? %></td>
-          <td><%= fmt_num(day[:cumulative_value] * 2.45, 3) unless day[:cumulative_value].nil? %></td>
+          <td><%= fmt_num(in_to_mm(day[:value]), 3) unless day[:value].nil? %></td>
+          <td><%= fmt_num(in_to_mm(day[:cumulative_value]), 3) unless day[:cumulative_value].nil? %></td>
         </tr>
       <% end %>
       </tbody>
diff --git a/app/views/weather/_data_tbl_insol.html.erb b/app/views/weather/_data_tbl_insol.html.erb
index bbfe332..4b379c0 100644
--- a/app/views/weather/_data_tbl_insol.html.erb
+++ b/app/views/weather/_data_tbl_insol.html.erb
@@ -22,7 +22,7 @@
             <td><%= i + 1 %></td>
             <td><%= day[:date] %></td>
             <td><%= fmt_num(day[:value], 2) %></td>
-            <td><%= fmt_num(day[:value] / 3.6, 2) unless day[:value].nil? %></td>
+            <td><%= fmt_num(mj_to_kwh(day[:value]), 2) unless day[:value].nil? %></td>
           </tr>
         <% end %>
       </tbody>
@@ -32,7 +32,7 @@
             <td></td>
             <td><%= k %>:</td>
             <td><%= fmt_num(v, 2) %></td>
-            <td><%= fmt_num(v / 3.6, 2) unless v.nil? %></td>
+            <td><%= fmt_num(mj_to_kwh(v), 2) unless v.nil? %></td>
           </tr>
         <% end %>
       </tfoot>
diff --git a/app/views/weather/_data_tbl_precip.html.erb b/app/views/weather/_data_tbl_precip.html.erb
index c6d32c5..363d477 100644
--- a/app/views/weather/_data_tbl_precip.html.erb
+++ b/app/views/weather/_data_tbl_precip.html.erb
@@ -25,8 +25,8 @@
           <td><%= day[:date] %></td>
           <td><%= fmt_num(day[:value], 2) %></td>
           <td><%= fmt_num(day[:cumulative_value], 2) %></td>
-          <td><%= fmt_num(day[:value] / 25.4, 3) unless day[:value].nil? %></td>
-          <td><%= fmt_num(day[:cumulative_value] / 25.4, 3) unless day[:cumulative_value].nil? %></td>
+          <td><%= fmt_num(mm_to_in(day[:value]), 3) unless day[:value].nil? %></td>
+          <td><%= fmt_num(mm_to_in(day[:cumulative_value]), 3) unless day[:cumulative_value].nil? %></td>
         </tr>
       <% end %>
       </tbody>
diff --git a/app/views/weather/precip.html.erb b/app/views/weather/precip.html.erb
index 9e09bdb..e59a4cf 100644
--- a/app/views/weather/precip.html.erb
+++ b/app/views/weather/precip.html.erb
@@ -20,7 +20,7 @@
 <% if @start_date %>
   <h4 id="map">Cumulative precipitation map for <%= @start_date.strftime("%b %-d") %> to <%= @date.strftime("%b %-d") %> (<%= pluralize((@start_date..@date).count, "day") %>)</h4>
 <% else %>
-  <h4 id="map">Precipiation map for <%= @date.strftime("%b %-d") %> (<%= pluralize((Date.current - @date).to_i, "day") %> ago)</h4>
+  <h4 id="map">Precipitation map for <%= @date.strftime("%b %-d") %> (<%= pluralize((Date.current - @date).to_i, "day") %> ago)</h4>
 <% end %>
 
 <%= render_async url_for(action: :map_image),