Ok, lets calculate the cost at 20yrs usage between electric storage heater and solar heater. Base on the max solar heater lifetime. (some claim at 15yrs)

Solar heater
Price range at RM5.5k.
Maintenance 4x in 20yrs - 4x900=RM3.6k
Total usage cost - RM5500 + RM3600 = RM9100

Storage heater
Price range at RM850. (68L Joven)
Usage perday boil once perday at for 60min at 3kw. 3kw x 365/12 = 91.25kwh/mth. If your bill is RM100/mth, that is 0.28 x 91.25 = RM25.55/mth
For 20yrs electric usage - RM25.55 x 12 x 20 =RM6132
Maintenance - For safety reason and lifespan, give it 10yrs to change once. So in 20yrs require 2unit. And the 2nd unit price might be up. Put it at RM850 +RM200 = RM1050
Total usage cost - RM850 + RM6132 + RM1050 = RM8032.

I will use solar heater for safety reason. Storage heater for the cost usage.

I think there is something wrong with your unit.

1.5yrs is crazy short life. Doesn't makesense every 1.5yrs got to change the heater.

weikee how long the heater last ?

If water is an issue, solar storage may also cause problems. The solar storage is also metal/s.steel and many piping inside the solar too.

I don't buy their word. It still doesn't make sense.

How much is the heater cost change ?

Why you still use it when the repairing cost is expensive. Those cost yrs add up can buy a instant heater which have no problem with the heater.

This is totally a design product failure. Nobody will buy a storage heater is the heater only last that short period.

Where got in Malaysia. I don't have problem since move in 2011, and i stay in Malaysia.

Probably this is just your case.

Not all. weikee unit been using for 7yrs now.

Why don't change the whole unit? 2nd time spoiled already have to consider hard not to continue use that crap heater anymore.

Storage heater not that expensive either.

Landed, USJ area, i am using 3M AP902 for incoming filter.

Doubt so, how is your house water (direct) If your water is ok for laundry, it will be okay to be use for storage heater. 

Have you seen the damage heating element? how is it look like?

Your neighbour heater is also same model and from developer ?

Check the model and Google see any complain on this particular model.

Developer will not choose the best model for you guy. They look for the cheapest and most basic model. You can't complain right? That is how easy to earn money.

If its lime/calcium build up can always sand it off. Look like your water need some filtering.

Is the element break? not generating heat. This usually happen when is too hot usually only happen if its "dry burn" without water or the element is not 100% into the water.

mcb trip or rcd trip?

Erm.... 
Maybe you don't know the difference between rcd and mcb.

Mind to take a picture?

Erm.... 
Maybe you don't know the difference between rcd and mcb.

Mind to take a picture?

Wow.
A 63 amp 2pole mcb tripping.

You have some problem.
1. The solar heater don't have internal protection from dry burn and load protection.

2. You don't have a dedicated mcb for the heater.
3.  I also suspect the contact point for the mcb are loose. Get a wireman to come and check.

Go and change the new storage heater la.

Add in an additional RCD beside the ON/OFF heater switch.

Why you still want to use a heater that every 1.5yrs got to repair ?

i agree with ozak.

your heater unit has inherent problems.
also, if changing unit just get the wireman to install the dedicated mcb/rcbo for the heater. and at the same time check the contacts for all the mcb.

Can you let me know,

1) Is you home hot water consumption is high? You guys bath at the same time in all the bathroom ? What is the pattern of usage everyday?
2) your storage heater supply to how many bathroom ? Kitchen ? WM?
3) What is the storage heater capacity and power?
4) heater ON for 24hr ? Or when off and when on ?