Standard boiler efficiency ratings can be compared here: http://www.ncm-pcdb.org.uk/sap/searchpod.jsp?id=17Thanks for the responses, it's appreciated.
I would have been helpful if Atmos published some efficiency figures for boilers in the same way cars quote things like 'miles per gallon', else how can you compare them?
Is it enough to state how much heat can be generated without saying how much power is used?
This is yours:
http://www.ncm-pcdb.org.uk/sap/pcdbdetails.jsp?pid=26&id=005983&type=105&mid=000141