a friend of mine, needs a imported UPS e.g APC etc. which model and makes I should recommend him ? From where in Lahore he can buy it ? what should be the battery size ?
Any 1000VA should be enough to handle this situation. I am not sure about purchase location in Lahore but Hall Road / Hafeez Center might be good starting point for such items.
Regarding battery size, the rule of thumb is "the bigger the better" especially in Lahore.
any recommended brand ?
APC or Homage / Mercury
Also look for Ecostar its emerging brand and enjoying good reputation. My neighbour is using it and satisfied
very good info about UPS facilities and its capacity
They all work just about the same, I must ask how much budget do you have. A 1000VA APC 24V UPS should serve the purpose for a good couple of years.