Another option is to direct vent it right out thru the brick if the masonry structure is at one end of the house. I helped a bud install an Accentra that way last summer. We still brought the liner up thru the damper so we didn't have to deal with the steel heat form enclosure. I simply fabricated a small aluminum cap & siliconed it to the flue tile on top. We used the Harman pass thru so he had an OAK for combustion air. No need to get up top come cleaning time, either...
