diff --git a/app/helpers/cache_keys_helper.rb b/app/helpers/cache_keys_helper.rb
index 6bcd8ca91..be23439dd 100644
--- a/app/helpers/cache_keys_helper.rb
+++ b/app/helpers/cache_keys_helper.rb
@@ -22,4 +22,9 @@ module CacheKeysHelper
     user_status
   end
 
+  # when commentable id and type are used but no need to update cache on updated_at changes
+  def commentable_cache_key(commentable)
+    "#{commentable.class.name}-#{commentable.id}"
+  end
+
 end
\ No newline at end of file
diff --git a/app/models/comment.rb b/app/models/comment.rb
index efa9ec7a0..233736824 100644
--- a/app/models/comment.rb
+++ b/app/models/comment.rb
@@ -2,7 +2,7 @@ class Comment < ActiveRecord::Base
   acts_as_paranoid column: :hidden_at
   include ActsAsParanoidAliases
   acts_as_votable
-  has_ancestry
+  has_ancestry touch: true
 
   attr_accessor :as_moderator, :as_administrator
 
diff --git a/app/views/comments/_comment.html.erb b/app/views/comments/_comment.html.erb
index d29c19ebe..0ac6b9be1 100644
--- a/app/views/comments/_comment.html.erb
+++ b/app/views/comments/_comment.html.erb
@@ -1,102 +1,104 @@
-<div class="row">
-	<div id="<%= dom_id(comment) %>" class="comment small-12 column">
+<% cache [locale_and_user_status(comment), comment, commentable_cache_key(@commentable), comment.author, (@comment_flags[comment.id] if @comment_flags)] do %>
+  <div class="row">
+  	<div id="<%= dom_id(comment) %>" class="comment small-12 column">
 
-    <% if comment.hidden? || comment.user.hidden? %>
-      <% if select_children(@comments, comment).size > 0 %>
-        <div class="is-deleted">
-          <p><%= t("debates.comment.deleted") %></p>
-        </div>
-      <% end %>
-    <% else %>
-      <% if comment.as_administrator? %>
-        <%= image_tag("admin_avatar.png", size: 32, class: "admin-avatar left") %>
-      <% elsif comment.as_moderator? %>
-        <%= image_tag("moderator_avatar.png", size: 32, class: "moderator-avatar left") %>
+      <% if comment.hidden? || comment.user.hidden? %>
+        <% if select_children(@comments, comment).size > 0 %>
+          <div class="is-deleted">
+            <p><%= t("debates.comment.deleted") %></p>
+          </div>
+        <% end %>
       <% else %>
-        <% if comment.user.organization? %>
-          <%= image_tag("collective_avatar.png", size: 32, class: "avatar left") %>
+        <% if comment.as_administrator? %>
+          <%= image_tag("admin_avatar.png", size: 32, class: "admin-avatar left") %>
+        <% elsif comment.as_moderator? %>
+          <%= image_tag("moderator_avatar.png", size: 32, class: "moderator-avatar left") %>
         <% else %>
-          <%= avatar_image(comment.user, seed: comment.user_id, size: 32, class: "left") %>
-        <% end %>
-        <% if comment.user.hidden? %>
-          <i class="icon-deleted user-deleted"></i>
-        <% end %>
-      <% end %>
-
-      <div class="comment-body">
-        <div class="comment-info">
-
-          <% if comment.as_administrator? %>
-            <span class="user-name"><%= t("debates.comment.admin") %> #<%= comment.administrator_id%></span>
-          <% elsif comment.as_moderator? %>
-            <span class="user-name"><%= t("debates.comment.moderator") %> #<%= comment.moderator_id%></span>
+          <% if comment.user.organization? %>
+            <%= image_tag("collective_avatar.png", size: 32, class: "avatar left") %>
           <% else %>
+            <%= avatar_image(comment.user, seed: comment.user_id, size: 32, class: "left") %>
+          <% end %>
+          <% if comment.user.hidden? %>
+            <i class="icon-deleted user-deleted"></i>
+          <% end %>
+        <% end %>
 
-            <% if comment.user.hidden? %>
-              <span class="user-name"><%= t("debates.comment.user_deleted") %></span>
+        <div class="comment-body">
+          <div class="comment-info">
+
+            <% if comment.as_administrator? %>
+              <span class="user-name"><%= t("debates.comment.admin") %> #<%= comment.administrator_id%></span>
+            <% elsif comment.as_moderator? %>
+              <span class="user-name"><%= t("debates.comment.moderator") %> #<%= comment.moderator_id%></span>
             <% else %>
-              <span class="user-name"><%= comment.user.name %></span>
-              <% if comment.user.official? %>
+
+              <% if comment.user.hidden? %>
+                <span class="user-name"><%= t("debates.comment.user_deleted") %></span>
+              <% else %>
+                <span class="user-name"><%= comment.user.name %></span>
+                <% if comment.user.official? %>
+                  &nbsp;&bullet;&nbsp;
+                  <span class="label round level-<%= comment.user.official_level %>">
+                    <%= comment.user.official_position %>
+                  </span>
+                <% end %>
+              <% end %>
+              <% if comment.user.verified_organization? %>
                 &nbsp;&bullet;&nbsp;
-                <span class="label round level-<%= comment.user.official_level %>">
-                  <%= comment.user.official_position %>
+                <span class="label round is-association">
+                  <%= t("shared.collective") %>
                 </span>
               <% end %>
-            <% end %>
-            <% if comment.user.verified_organization? %>
-              &nbsp;&bullet;&nbsp;
-              <span class="label round is-association">
-                <%= t("shared.collective") %>
-              </span>
-            <% end %>
-            <% if comment.user_id == @commentable.author_id %>
-              &nbsp;&bullet;&nbsp;
-              <span class="label round is-author">
-                <%= t("debates.comment.author") %>
-              </span>
+              <% if comment.user_id == @commentable.author_id %>
+                &nbsp;&bullet;&nbsp;
+                <span class="label round is-author">
+                  <%= t("debates.comment.author") %>
+                </span>
+              <% end %>
+
             <% end %>
 
+            &nbsp;&bullet;&nbsp;<time><%= l comment.created_at.to_datetime, format: :datetime %></time>
+          </div>
+
+          <% if comment.as_administrator? %>
+            <p class="comment-user is-admin"><%= comment.body %></p>
+          <% elsif comment.as_moderator? %>
+            <p class="comment-user is-moderator"><%= comment.body %></p>
+          <% elsif comment.user.official? && comment.user_id == @commentable.author_id %>
+            <p class="comment-user level-<%= comment.user.official_level %> is-author"><%= comment.body %></p>
+          <% elsif comment.user.official? %>
+            <p class="comment-user level-<%= comment.user.official_level %>"><%= comment.body %></p>
+          <% elsif comment.user_id == @commentable.author_id %>
+            <p class="comment-user is-author"><%= comment.body %></p>
+          <% else %>
+            <p class="comment-user"><%= comment.body %></p>
           <% end %>
+          <span id="<%= dom_id(comment) %>_votes" class="comment-votes right">
+            <%= render 'comments/votes', comment: comment %>
+          </span>
 
-          &nbsp;&bullet;&nbsp;<%= time_ago_in_words(comment.created_at) %>
+          <div class="reply">
+            <%= t("debates.comment.responses", count: select_children(@comments, comment).size) %>
+
+            <% if user_signed_in? %>
+              <span class="divider">&nbsp;|&nbsp;</span>
+              <%= link_to(comment_link_text(comment), "",
+                          class: "js-add-comment-link", data: {'id': dom_id(comment)}) %>
+
+              <%= render 'comments/actions', comment: comment %>
+
+              <%= render 'comments/form', {commentable: @commentable, parent_id: comment.id, toggeable: true} %>
+            <% end %>
+          </div>
         </div>
-
-        <% if comment.as_administrator? %>
-          <p class="comment-user is-admin"><%= comment.body %></p>
-        <% elsif comment.as_moderator? %>
-          <p class="comment-user is-moderator"><%= comment.body %></p>
-        <% elsif comment.user.official? && comment.user_id == @commentable.author_id %>
-          <p class="comment-user level-<%= comment.user.official_level %> is-author"><%= comment.body %></p>
-        <% elsif comment.user.official? %>
-          <p class="comment-user level-<%= comment.user.official_level %>"><%= comment.body %></p>
-        <% elsif comment.user_id == @commentable.author_id %>
-          <p class="comment-user is-author"><%= comment.body %></p>
-        <% else %>
-          <p class="comment-user"><%= comment.body %></p>
+      <% end %>
+      <div class="comment-children">
+        <% select_children(@comments, comment).each do |child| %>
+          <%= render 'comments/comment', comment: child %>
         <% end %>
-        <span id="<%= dom_id(comment) %>_votes" class="comment-votes right">
-          <%= render 'comments/votes', comment: comment %>
-        </span>
-
-        <div class="reply">
-          <%= t("debates.comment.responses", count: select_children(@comments, comment).size) %>
-
-          <% if user_signed_in? %>
-            <span class="divider">&nbsp;|&nbsp;</span>
-            <%= link_to(comment_link_text(comment), "",
-                        class: "js-add-comment-link", data: {'id': dom_id(comment)}) %>
-
-            <%= render 'comments/actions', comment: comment %>
-
-            <%= render 'comments/form', {commentable: @commentable, parent_id: comment.id, toggeable: true} %>
-          <% end %>
-        </div>
       </div>
-    <% end %>
-  <div class="comment-children">
-    <% select_children(@comments, comment).each do |child| %>
-      <%= render 'comments/comment', comment: child %>
-    <% end %>
+    </div>
   </div>
-</div>
-</div>
\ No newline at end of file
+<% end %>
\ No newline at end of file
diff --git a/app/views/comments/_form.html.erb b/app/views/comments/_form.html.erb
index 5c9f4eab2..3704b2fa1 100644
--- a/app/views/comments/_form.html.erb
+++ b/app/views/comments/_form.html.erb
@@ -1,26 +1,28 @@
-<% css_id = parent_or_commentable_dom_id(parent_id, commentable) %>
-<div id="js-comment-form-<%= css_id %>" <%= "style='display:none'".html_safe if toggeable %>>
-  <%= form_for [commentable, Comment.new], remote: true do |f| %>
-    <%= label_tag "comment-body-#{css_id}", t("comments.form.leave_comment") %>
-    <%= f.text_area :body, id: "comment-body-#{css_id}", label: false %>
-    <%= f.hidden_field :commentable_type, value: commentable.class.name %>
-    <%= f.hidden_field :commentable_id, value: commentable.id %>
-    <%= f.hidden_field :parent_id, value: parent_id %>
+<% cache [locale_and_user_status, parent_id, commentable_cache_key(commentable)] do %>
+  <% css_id = parent_or_commentable_dom_id(parent_id, commentable) %>
+  <div id="js-comment-form-<%= css_id %>" <%= "style='display:none'".html_safe if toggeable %>>
+    <%= form_for [commentable, Comment.new], remote: true do |f| %>
+      <%= label_tag "comment-body-#{css_id}", t("comments.form.leave_comment") %>
+      <%= f.text_area :body, id: "comment-body-#{css_id}", label: false %>
+      <%= f.hidden_field :commentable_type, value: commentable.class.name %>
+      <%= f.hidden_field :commentable_id, value: commentable.id %>
+      <%= f.hidden_field :parent_id, value: parent_id %>
 
-    <%= f.submit comment_button_text(parent_id), class: "button radius small inline-block" %>
+      <%= f.submit comment_button_text(parent_id), class: "button radius small inline-block" %>
+
+      <% if can? :comment_as_moderator, commentable %>
+        <div class="right">
+          <%= f.check_box :as_moderator, id: "comment-as-moderator-#{css_id}", label: false %>
+          <%= label_tag "comment-as-moderator-#{css_id}", t("comments.form.comment_as_moderator"), class: "checkbox" %>
+        </div>
+      <% end %>
+      <% if can? :comment_as_administrator, commentable %>
+        <div class="right">
+          <%= f.check_box :as_administrator, id: "comment-as-administrator-#{css_id}",label: false %>
+          <%= label_tag "comment-as-administrator-#{css_id}", t("comments.form.comment_as_admin"), class: "checkbox" %>
+        </div>
+      <% end %>
 
-    <% if can? :comment_as_moderator, commentable %>
-      <div class="right">
-        <%= f.check_box :as_moderator, id: "comment-as-moderator-#{css_id}", label: false %>
-        <%= label_tag "comment-as-moderator-#{css_id}", t("comments.form.comment_as_moderator"), class: "checkbox" %>
-      </div>
     <% end %>
-    <% if can? :comment_as_administrator, commentable %>
-      <div class="right">
-        <%= f.check_box :as_administrator, id: "comment-as-administrator-#{css_id}",label: false %>
-        <%= label_tag "comment-as-administrator-#{css_id}", t("comments.form.comment_as_admin"), class: "checkbox" %>
-      </div>
-    <% end %>
-
-  <% end %>
-</div>
+  </div>
+<% end %>
diff --git a/app/views/debates/_comments.html.erb b/app/views/debates/_comments.html.erb
index 5fbea960d..2a2fb518e 100644
--- a/app/views/debates/_comments.html.erb
+++ b/app/views/debates/_comments.html.erb
@@ -1,28 +1,29 @@
-<section class="row-full comments">
-  <div class="row">
-    <div id="comments" class="small-12 column">
+<% cache [locale_and_user_status, commentable_cache_key(@debate), @all_visible_comments, @all_visible_comments.map(&:author), @debate.comments_count, @comment_flags] do %>
+  <section class="row-full comments">
+    <div class="row">
+      <div id="comments" class="small-12 column">
+        <h2>
+          <%= t("debates.show.comments_title") %>
+          <span>(<%= @debate.comments_count %>)</span>
+        </h2>
 
-      <h2>
-        <%= t("debates.show.comments_title") %>
-        <span>(<%= @debate.comments_count %>)</span>
-      </h2>
+        <% if user_signed_in? %>
+          <%= render 'comments/form', {commentable: @debate, parent_id: nil, toggeable: false} %>
+        <% else %>
+        <br>
 
-      <% if user_signed_in? %>
-        <%= render 'comments/form', {commentable: @debate, parent_id: nil, toggeable: false} %>
-      <% else %>
-      <br>
+        <div class="alert-box radius info">
+          <%= t("debates.show.login_to_comment",
+              signin: link_to(t("votes.signin"), new_user_session_path),
+              signup: link_to(t("votes.signup"), new_user_registration_path)).html_safe %>
+          </div>
+        <% end %>
 
-      <div class="alert-box radius info">
-        <%= t("debates.show.login_to_comment",
-            signin: link_to(t("votes.signin"), new_user_session_path),
-            signup: link_to(t("votes.signup"), new_user_registration_path)).html_safe %>
-        </div>
-      <% end %>
-
-      <% @root_comments.each do |comment| %>
-        <%= render 'comments/comment', comment: comment  %>
-      <% end %>
-      <%= paginate @root_comments %>
+        <% @root_comments.each do |comment| %>
+          <%= render 'comments/comment', comment: comment  %>
+        <% end %>
+        <%= paginate @root_comments %>
+      </div>
     </div>
-  </div>
-</section>
\ No newline at end of file
+  </section>
+<% end %>
\ No newline at end of file
diff --git a/config/locales/rails.en.yml b/config/locales/rails.en.yml
index cb5bdc38f..e45dfce7e 100644
--- a/config/locales/rails.en.yml
+++ b/config/locales/rails.en.yml
@@ -20,3 +20,6 @@
 # available at http://guides.rubyonrails.org/i18n.html.
 
 en:
+  time:
+    formats:
+      datetime: "%Y-%m-%d %H:%M:%S"
diff --git a/config/locales/rails.es.yml b/config/locales/rails.es.yml
index 9a6e698d2..31cc02e92 100644
--- a/config/locales/rails.es.yml
+++ b/config/locales/rails.es.yml
@@ -196,4 +196,5 @@ es:
       default: "%A, %d de %B de %Y %H:%M:%S %z"
       long: "%d de %B de %Y %H:%M"
       short: "%d de %b %H:%M"
+      datetime: "%d/%m/%Y %H:%M:%S"
     pm: pm
\ No newline at end of file
diff --git a/spec/features/comments_spec.rb b/spec/features/comments_spec.rb
index 2bdd380bd..40e75a281 100644
--- a/spec/features/comments_spec.rb
+++ b/spec/features/comments_spec.rb
@@ -14,7 +14,7 @@ feature 'Comments' do
     comment = Comment.last
     within first('.comment') do
       expect(page).to have_content comment.user.name
-      expect(page).to have_content time_ago_in_words(comment.created_at)
+      expect(page).to have_content I18n.l(comment.created_at, format: :datetime)
       expect(page).to have_content comment.body
     end
   end