You old heater model number would help
SAVE THE DOOR FROM YOUR OLD HEATER!!!!!!!!!! The new door will most likely be white.
Google …...Suburban RV water heater…..and….Atwood RV water heater.
They should have a chart with the dimensions….or their phone number
OR RV Parts and Accessories for Sale - PPL Motor Homes
Or call Inland RV...Toll-Free: 800-877-7311 ( Airstream Specialists/Experts )
You could have a new heater on your doorstep in a matter of days