Effect of Transformer AC/AC: 27W Ingoing, 20VA Outgoing

[johann1301]

I have a transformer AC/AC which says that the ingoing effect is 27W and the outgoing effect is 20VA.

which means it loses about 7 J every second to heat. (?)

Any idea as to why it is written as VA instead of W on the outgoing line?

 

[CWatters]

Google "What is the difference between VA and W" without the quotes.

 

[johann1301]

Thanks:)