Just get the Panasonic.

Any water heater will not hot enough if the flow of water is too fast.

Not reliable electronic component.

That is why need a 2nd RCD near the heater. At least it is not a electronic component.

Life depend on the heater safety component is dangerous.

Are you telling the Alpha no good ?

You said it is good is because technician will visit if problem. I don't see the point of good on that heater unit.

Than only in warranty condition. Finish warranty, no coming ?

Price ?

Ok boss.

Normally such rare heater in here will cost a bomb. They can claim how high tech and save cost, but the heater initial cost is high that can't return back the cost when calculate the usage.

Few hundred expensive. But price still afford I guess.

Go and try. Let us know here.

Makesure it safe enough. Don't pay too much attention on the high tech. But not safe to use.

If you see the spec clearly, it didn't save much or pretty non. It selling point is the heating element.

Joven take 30min at 3kw to boil the water to 70°.

Hydro1 take 36min at 1.5kw to boil to 44°c. See the temp different.

I don't see the Hydro1 save in electricity.

Hydro1 have 30L, 50L and 80L. Check at the Specification.

Base on the Eco30 L, 36min - 44°. If reach to 70° will take - 70/44x36= 57min.

Base on Eco50L, 45min - 44°. If reach to 70° will take - 70/44x45= 71min.

Base on the Joven JH35L, 60min - 70°.

Base on the Joven JH50L, 90min - 70°.

Try la. no worry.

Later let us know here.

I don't see any good point of 1.5kw element. It is just lower power element. While Joven have 3kw and 1.5kw element.

In term of save, 50L have more advantage. Another is, it can adjust the temperature you want.

But for me, it is useless as the storage heater will be hide inside ceiling. If many people using, you have to set it max to reduce the hot water usage ratio.

The only point worry is, how long the heating element can last. And what is the cost to replace. This might turn you off.

Imagine have a tong gas size at the corner of the bathroom. That is the 40-50L size of a storage heater. With the piping and wiring, it is an eye sore in your bathroom. If with a small bathroom, it look crush in there.

Storage heater have to install height above. Who want to climb ladder adjust the knob everytime ? It is not same as instant heater height level. You going to knock your head with that tong gas size heater in the bathroom.

You can mix the water at the tap to get the right temperature you want. It is not same function as instant heater. There is no logic to adjust the temp...before use ?

It is not necessary to install a pressure gauge for the incoming water. I believe the tank can stand well above the normal house water pressure.

The pressure relieve valve don't have the gauge reading. It is just a spring load valve mechanism. You can test it once a yrs by pulling the shaft ring. So not necessary to be eye visible the storage heater. There is nothing to see at all.

Go for storage.

Instant not mean for strong pressure.

If he mean the instant water heater with pump have a rain shower, he will be disappoint with the pressure.

If he mean without pump instant heater with rain shower head, 3.6kw might not be enough. And that is max you can set.

Why risk to gambler on instant ?

Just straight go for storage. You get 100% satisfy result from the installation. All his requirement can be meet with got extra controllable heat.

For me, the meaning "rain shower" is not high pressure bath. But I don't think people will understand what mean of "Rain Shower".

Your instant heater pump cannot coupe with this big shower head. It not enough power to pump the large amount of water for this big shower head.

The most bigger size for instant heater is 7" head. The istant heater have to design for the shower head, Not any instant heater.

Another problem is the water temperature will drop alot. This is due to

1) high flow water cannot absorb enough heat from the heater.
2) Because of the slow water drop from shower heat, the water been cold down by the air between the water travel from the head to your body. You can feel the water colder than using the hand shower.

Use water heater tank.

Follow the contractor advise.

This point look dangerous and no earth wire.

It is better to direct the wire into the heater instead a wall socket. With a switch outside the bathroom.