It is probably going to be more expensive to have two meters, as you will have to pay a fee for each of them. However, if you would like your tenant to pay for the electricity costs associated with his or her apartment, you will need to get a second meter.
We recommend you discuss your project with a master electrician. You should know that the work done will be at your expense, and that your master electrician will contact us so that we may carry out the necessary work and install the meter. You will then be billed for the work done.