Understand that thanks.

 

My comment about testing was because I assume the danger of battery models is the battery going flat?

 

There are some quite sophisticated multisensor wireless linked battery models that save quite a bit.

 

Saving £200 would be very nice unless there is a good reason for going with mains?

Mains smoke alarms run on mains and if the mains is lost then the battery should take over.

Battery only models should have two battery supply's for the sounder part. One primary battery for normal day to day and a secondary battery should the primary battery fail. Not to be confused with standard battery operated smoke alarms.

I don't know to any domestic primary & secondary battery powered smoke alarms, unless someone has a web link.

 

90% of my domestic customers always say no when I offer to install some smoke alarms. They always say "We have a battery one there" we normal look to find no smoke alarm on the ceiling as its in the kitchen drawer because the toaster keeps setting it off (should be heat detector in the kitchens).