Outlook365 draining battery on Macbook Air

Question

Since upgrading to Yosemite and installing Outlook365, the battery is draining on my MBA.  The fan is on and the machine is running hot. The problem seems to be Oulook365 that's using a really high level of CPU.  If I switch on "Work Offline" or exit Outlook the problem goes away.
Has anyone seen this and have any suggestions on how to rectify?
Here's the output from Etrecheck:
Problem description:
Battery problems with Outlook365
EtreCheck version: 2.1.1 (104)
Report generated 7 December 2014 00:00:11 GMT
Hardware Information: ℹ️
  MacBook Air (Verified)
  MacBook Air - model: MacBookAir6,2
  1 1.4 GHz Intel Core i5 CPU: 2-core
  8 GB RAM Not upgradeable
  BANK 0/DIMM0
  4 GB DDR3 1600 MHz ok
  BANK 1/DIMM0
  4 GB DDR3 1600 MHz ok
  Bluetooth: Good - Handoff/Airdrop2 supported
  Wireless:  en0: 802.11 a/b/g/n/ac
Video Information: ℹ️
  Intel HD Graphics 5000 -
  Color LCD 1440 x 900
System Software: ℹ️
  OS X 10.10.1 (14B25) - Uptime: 2 days 12:34:21
Disk Information: ℹ️
  APPLE SSD SD0256F disk0 : (251 GB)
  S.M.A.R.T. Status: Verified
  EFI (disk0s1) <not mounted> : 210 MB
  Recovery HD (disk0s3) <not mounted>  [Recovery]: 650 MB
  MacOSX (disk1) / : 249.67 GB (196.75 GB free)
  Encrypted AES-XTS Unlocked
  Core Storage: disk0s2 250.01 GB Online
USB Information: ℹ️
  Apple Internal Memory Card Reader
  Apple Inc. BRCM20702 Hub
  Apple Inc. Bluetooth USB Host Controller
Thunderbolt Information: ℹ️
  Apple Inc. thunderbolt_bus
Gatekeeper: ℹ️
  Mac App Store and identified developers
Kernel Extensions: ℹ️
  /Library/Application Support/Symantec/AntiVirus
  [loaded] com.symantec.kext.SymAPComm (12.2f1 - SDK 10.6) [Support]
  /Library/Extensions
  [loaded] com.symantec.kext.ndcengine (1.0f2 - SDK 10.6) [Support]
  [not loaded] org.virtualbox.kext.VBoxDrv (4.2.16) [Support]
  [not loaded] org.virtualbox.kext.VBoxNetAdp (4.2.16) [Support]
  [not loaded] org.virtualbox.kext.VBoxNetFlt (4.2.16) [Support]
  [not loaded] org.virtualbox.kext.VBoxUSB (4.2.16) [Support]
  /System/Library/Extensions
  [loaded] com.symantec.kext.internetSecurity (5.2f1 - SDK 10.6) [Support]
  [loaded] com.symantec.kext.ips (3.5f1 - SDK 10.6) [Support]
Startup Items: ℹ️
  VirtualBox: Path: /Library/StartupItems/VirtualBox
  Startup items are obsolete in OS X Yosemite
Launch Agents: ℹ️
  [running] com.symantec.uiagent.application.plist [Support]
  [running] jp.co.canon.CUPSCMFP.BG.plist [Support]
  [running] jp.co.canon.UFR2.BG.plist [Support]
  [not loaded] org.virtualbox.vboxwebsrv.plist [Support]
Launch Daemons: ℹ️
  [loaded] com.adobe.fpsaud.plist [Support]
  [loaded] com.microsoft.office.licensing.helper.plist [Support]
  [loaded] com.symantec.liveupdate.daemon.ondemand.plist [Support]
  [loaded] com.symantec.liveupdate.daemon.plist [Support]
  [not loaded] com.symantec.sep.migratesettings.plist [Support]
  [running] com.symantec.sharedsettings.plist [Support]
  [running] com.symantec.symdaemon.plist [Support]
User Launch Agents: ℹ️
  [running] com.spotify.webhelper.plist [Support]
User Login Items: ℹ️
  UNKNOWN UNKNOWN (missing value)
  iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)
  Dropbox Application (/Applications/Dropbox.app)
  Spotify Application (/Applications/Spotify.app)
Internet Plug-ins: ℹ️
  FlashPlayer-10.6: Version: 15.0.0.239 - SDK 10.6 [Support]
  QuickTime Plugin: Version: 7.7.3
  Flash Player: Version: 15.0.0.239 - SDK 10.6 [Support]
  Default Browser: Version: 600 - SDK 10.10
  SharePointBrowserPlugin: Version: 14.4.5 - SDK 10.6 [Support]
  Scorch: Version: Unknown - SDK 10.2 [Support]
  MeetingJoinPlugin: Version: Unknown - SDK 10.6 [Support]
  JavaAppletPlugin: Version: 15.0.0 - SDK 10.10 Check version
Safari Extensions: ℹ️
  Extensions: No such file or directory
3rd Party Preference Panes: ℹ️
  Flash Player  [Support]
  PrintOptionPane  [Support]
  Symantec QuickMenu  [Support]
Time Machine: ℹ️
  Time Machine not configured!
Top Processes by CPU: ℹ️
    156% Microsoft Outlook
      12% WindowServer
      2% Dropbox
      1% AppleSpell
      1% sysmond
Top Processes by Memory: ℹ️
  395 MB Microsoft Outlook
  335 MB SymDaemon
  215 MB com.apple.WebKit.WebContent
  198 MB mds_stores
  155 MB Safari
Virtual Memory Information: ℹ️
  946 MB Free RAM
  4.73 GB Active RAM
  1.52 GB Inactive RAM
  1.05 GB Wired RAM
  26.53 GB Page-ins
  8 MB Page-outs
Diagnostics Information: ℹ️
  Dec 6, 2014, 04:21:40 PM Microsoft Outlook_2014-12-06-162140_fatboy-2.cpu_resource.diag [Details]
  Dec 6, 2014, 10:09:54 AM com.apple.WebKit.WebContent_2014-12-06-100954_fatboy-2.cpu_resource.diag [Details]
  Dec 5, 2014, 03:43:37 PM SymDaemon_2014-12-05-154337_fatboy-2.cpu_resource.diag [Details]
  Dec 5, 2014, 12:02:24 PM Microsoft Outlook_2014-12-05-120224_fatboy-2.cpu_resource.diag [Details]
  Dec 4, 2014, 05:35:39 PM Microsoft Outlook_2014-12-04-173539_fatboy-2.cpu_resource.diag [Details]
  Dec 4, 2014, 11:32:08 AM Microsoft Outlook_2014-12-04-113208_fatboy-2.cpu_resource.diag [Details]
  Dec 4, 2014, 11:26:26 AM Self test - passed

Answer 1

Hi there. I also have a few questions on this point, please.
You say "delete the ones you think you don't need" but what do I need and what do I not need, please?! I have a new (July 2012) MacBook Air 13" and I have also been concerned about the battery running down quickly - in a couple of hours when watching films. Reading a couple of threads I have identified Safari Silverlight as still running after I have quit Safari but I have also been trying to work out what the other processes are that are in the Activity Monitor list and which ones I need, which I don't! Most of them are at 0.0% of CPU and the highest is only Safari at 12%, but there are 68 processes in there!
Also, I have looked at the Apple Support page given above about battery life and mine is already on its 11th cycle, full charge capacity 6524. I have read elsewhere that I should use my Air plugged in when near a power source - is this the best thing to do to conserve battery life? I currently use it mostly around the house, near power sources, and it is intended also to replace the PC desktop when that dies, but I bought an Air to be portable too.
I have the Default Settings for display, sleep etc.
All suggestions and advice are extremely welcome - many thanks!