You should have your air conditioning system serviced before the weather starts to heat up. Inefficient systems will not only put a strain on the units operation but also the electricity grid. By cleaning or replacing the filters and clearing out the evaporator, the efficiency of the system will dramatically improve and keep running cost down.
User-Replaceable Battery Type (9V Alkaline Battery)
It has been specified by the Australian Standard (AS) 3786:2014 that the standby mode in a smoke alarm should be capable to run for at least one year before the batter low-fault is shown. Followed by 30 days of a battery fault warning, the alarm should buzz for at least 4 minutes.