New gas furnace, 80-90 or 95% efficient?

[Jeff S.]

While my 44 year old gas furnace in a rental runs good the management company had a furnace guy say it is in bad shape. It is actually running good but hard to argue the point since 44 is pretty old. BTW my home furnace is 42 and runs great. New furnace good for 15 years.

Contractor recommends 80% (for a rental) because of maintenance issues with extra venting and water condensation that needs to be removed. Hard to get money back for extra cost but this is a more expensive ($2400) rental and hate to cheap out. Price differences about 1k to 1.3k. It has old central air too will need help soon too. Thoughts?