Hello there, My names James Etherington. I am a qualified and legal electrician from Nar 3 apartment 159. We supply and fit Card operated meters for aircon units for 150euros. It's a similar system optioned by most land lords where by you allow your tenants to purchase 10euro electricity cards which they use to top up the meter. The rates for the electric can be selected by the owner. Often this system is adopted if you currently have a keyholder. If this is the case, your keyholder will already be familiar with this system also as there are numerous properties with this installation. Please get in touch if you have any other questions and would like to purchase the system from us. Also we Supply and fit whole house surge protection, which is advisable as the electrical supply in Spain is quite dirty and the voltage prone to numerous spikes and surges. These can cause your appliances circuit boards to blow. This includes your aircon units and any other appliances of value.
My number is: 673576441 All the best, hope this information helps at the very least.
Aircon units tend to cost round about 20p per hour including tax per unit.