Recently I've been looking around for washer and dryer for my new house.

I realised there's different types of model and some with 2 in 1 washer & dryer combo machines.

However, I would like to know why washer has a bigger kg and dryer has less?

The salesman told me that you cannot put 7kg washer cloths into 7kg dyer.

And if I have a combo machine (7kg washer/ 5kg dryer), and full load the washer to 7kg, I will have to remove some cloths before it run in the dryer). If that's the case, then why I need a combo machine in the first place??

I dunno what he means.

Can anyone who is using a dryer explains the logic of the different KG volume in the both washer and dryer?

Should I get 2 in 1 combo machine?

Because if you put max load; the your cloths would be "compacted" together and the inner part would not dry.
However, because water still sip through; thus even with max load, water can still sip through for washing.

Anyway, there's some talk about washing machine and specs if you wish to pursue more: https://forum.lowyat.net/index.php?showtopic=751267