As a customer, how would I know they’ve done a heat loss calculator or the installer has done a DNO? 2022-05-10T15:51:50+01:0010 May 2022|FAQ Domestic|0 Comments You need to ask. Also heat loss calcs and Connect and Notify (DNO) is required as part of the MCS process so your installer should do that to remain MCS compliant. Share This Story, Choose Your Platform! FacebookXLinkedIn