The downside is they are not as efficient, nor compact, as something like brazed plate or tube-and-shell exchanger.

did not read all the replies, but if you were close in the area, i'd say "you backed out too soon". since you are far away and the seller/BP member clearly knew that, you are correct to feel uneasy. note to the seller/BP member - dont advertise as "turn key" if stuff still needs to be done to the house. turn key in most peoples minds means "i unlock the door and put my toothbrush in the medicine cabinet.

they dig down to more solid or heavily compacted ground.  

If the tenants move out, you could advertise to 'green' tenants who will attempt to use less electricity, water, gas, and trash.http://www.homedepot.com/p/StoreBound-Laundry-Pod-Non-Electrical-Compact-Portable-Washer-in-Green-LP001GRN/205034847?

I took a look at the zoning map for that area and it's all zoned CN, or compact neighborhood.

They punched a bunch a holes in the bottom and sides with a breaker on a backhoe, caved in the sides, filled with dirt and compact.

Allentown will be more compact, it will be more so middle class type properties mixed with lower end properties. 700 credit score is above average, you should be in good shape.

If it wasn't laid right on a compacted bed with rebar or remesh with stress joints then it's not worth saving.

The basement, why is it collecting water, has the soil compacted around the house?

feom the Reddit thread the site is down because of high load https://www.reddit.com/r/dataisbeautiful/comments/3z0tvi/dot_density_map_of_home_owners_vs_renters/.compact