A flueless gas fire in Ireland will always require you to have 2 vents fitted within the room. One fitted must be fitted at high level and 1 fitted at low level.
Flueless Gas Fires are generally upto 100% efficient -so you get upto 100% of the gas you use as heat in to the area. They range in heat output normally from 2 kilowatts to around 3.5 kilowatts.
-because are generally 100% efficient they will use 3.5 kilowatts of gas . Gas in Ireland is typically between 4-6 cent per kilowatt.
Example 3.5 by 6 cents = 21 cents per hour