My next plan is to replace the 5,000 Btu roof unit with a slightly larger by only 2-3 " 8,000 Btu window unit also with a larger 4" hose and a larger 4" blower. That should work much better as I am really satisfied with the performance of the small roof unit, it seamed to work great up to about 90 deg in full sunlight. I will add some pictures to this entry as I get started with the project.
I just ordered a 4" x 10 ft plastic hose from harbor freight in hopes that the blower will not be quite as loud.
Update: The hose arrived supper fast in 4-5 days...but has a very strong chemical - plastic smell, so I need to air it out for some time.
I just found and ordered this new water heater from Lowe's....But fast service and local PU is not in their book ....