Currently we have 5.5kg machine.
But I want to use a bigger one bz, we will use the machine once in a week(it will be very diff for us in the current state to use multiple times in the week). so I am trying for a bigger capacity to reduce number WM runs.
ok, so tell us the dimensions of your present IFB drum, get a tape measure and measure depth and height and post it over here (in cm).
DD has any maintenance issues compared to belt?
If the drum support goes its no different. That 10 yr motor gurantee, you will never use because the motor rarely gives trouble.
Also running the WM in less load like 30% will have any long-term impact on WM?
This is known as underloading, in terms of washing no, but in terms of spinning it can cause out of balance more often. What you do is add some extra towels to balance the load. Sometimes it works other times it will not. Just skip the spin in that case.
I am kind of inclined towards Sammy bz of no dd, how is Sammy in this field?
Sammy is DD but they don't talk about it. The way you tell is look at the drum volume of their models and compare with equivalent LG's. Bear in mind that models that were 5.5 kg 2 yrs back are now 6kg but are still the same volume.
Sammy is new to the game, they started in 2007, LG has been at it since 2001. How good sammy's after sales is or the quality is an open question. I know people that own sammy and are happy. They've yet to get a service done though. When it comes to looks the sammy is more attractive than lg or bosch. Just slam the door and listen to the noise and most people will have a good impression of the sammy going by the exterior. What the interior is like is known for less time. Whereas the bosch or LG are better known.
Am not sure why you don't want Bosch/Siemens. Your 7-yr old IFB uses Bosch parts. Bosch drums are the same as Siemens drums in the sense if drum support goes then the entire drum has to be replaced.
