Heads up...
As of September this year manufacturers will not be allowed to import or manufacture for sale in Spain conventional gas wáter heaters or conventional boilers into Spain. All boilers will need to be:
- balanced flu wáter heaters
- condensing boilers

Existing stocks can continue to be sold until exhausted.

So what?
1. They are more expensive
2. They need electric power to function

In the case of the boilers this is normal so shouldn't cause problems (excpt in installations running on solar - see the bit about an earth below).

In the case of wáter heaters there are many installed in houses where there is no 220V power available (running on 12V system) or generator only. Some are installed in places where there is no power available.

A secondary problem is that some boilers and heaters require an earth to correctly function. Most solar systems are installed without an earth or in a way that an earth wasn't deemed necessary.

So, just in case you are planning your big reform/rebuild/new build, take into account that you will need to have a power source for your wáter heater, if not today then in the future when your existing heater breaks down.