Does anyone have some comments on which is likely the preferred option in a mild (18*F) climate?

Monoblock looks easier to install with just water lines to the house. The freezing of these is a bit of a concern in a power failure though.

Split-type seems a bit more "traditional" in that its like a central air conditioner or boiler setup.

Thanks

John

Monoblock looks easier to install with just water lines to the house.

Correct. Just one box to install. It's faster. No refrigerant lines to and from house.

The freezing of these is a bit of a concern in a power failure though.

Exactly. Glycol anyone?

I livein a similar climate and I preferred the split option because I wanted to have some functions inside and not have to worry about the line freezing issue. And wanted to minimize the size of the outdoor unit.

you would definitely glycol the system if using the monobloc unless it just doesn't freeze in your area. Having most interface and function inside is of benefit as well. However, not having to mess with refrigerant lines is also a benefit in some cases, so each project needs to balance those pros and cons for themselves.