Don’t you hate it when you are talking to someone, and they start reading email on their phone? Aside from being a new technology faux-pas, there are other reasons to avoid checking your email every five seconds. Checking your email less often can also save your phones’ battery life.

When setting up email sync on mobile devices, users are often given options on push vs. poll, and options to change the timing for polling.  Since having the phone check for  email too often will kill your battery, what is the optimal setting to balance e-mail delivery and battery life?

Push vs. Poll – What’s Best for You?

Let’s start off with describing what we are talking about: push email is delivering each mail to the device as it arrives, while polling email is when your device makes regular checks to the email server for new messages (polling the server).

When I began thinking about push vs. poll, I assumed that push was always the best option.  However, as I began working through the way that connections are made, I began to realize that setting up a device to poll less often will significantly reduce the battery drain on my device and potentially improve my concentration and productivity.

Do the Math

Ok, now to walk through the data. (My assumptions and sample calculations are at the end of this post.)  If you get 25 emails per hour, email push costs 250J of energy, and polling costs between 30 and 600J/hour:

poll (min) J/hour savings

1

600

-58.33%

2

300

-16.67%

5

133

87.97%

10

79

216.46%

15

61

309.84%

20

52

380.77%

30

43

481.40%

60

34

635.29%

 

Five-minute polling uses 87 percent less energy, and 10-minute polling uses  >200 percent  less energy.

The break-even point for five-minute polling is 12 emails per hour, and for ten-minute polling, it’s 7 emails per hour.

What does all of this add up to? If you get fewer than seven emails per hour, push is the most efficient way to get your email.

Here is the kicker!  It is actually better for your battery to get email in real-time in evenings and on the weekend (when your e-mail load is hopefully lighter), and to poll at regular intervals during working hours.  I would hazard to guess that most professionals actually are doing the opposite, and their mobile batter life is suffering as a consequence.

Give it a shot, and tell me what you find out!