I agree with all of this. Hard wire if possible and battery back-up.
If you have gas appliances or fireplace plug in a Carbon Monoxide Detector near each.
I installed two smoke detectors in the garage, on the ceiling over each Morgan.
The loudest I could buy.
The toaster does set them off!!
TomS
Have to ask, Why do you make toast in the garage?
Otherwise agree, 100%
I wondered about the CH boiler as this is a modern condensing version with no openings to the room in which the boiler sits. The professional view is that a CO detector shouldn't be needed, but you never know and if the flu gets blocked then CO could seep into the room. So better to fit one.
Likewise the wood burner: running correctly all products of combustion should go up the flu, but again, you never know. Interestingly we had to have a 2" air pipe from outside fitted when we replaced an open fore with a wood burning stove, to ensure proper combustion.
