We had the inspection today and all the utilities (plumbing, heat, electric) are in need of a full replacement.

.- even if you don’t think you have problems with things like AC, heating, plumbing, etc., have it inspected.

We plan to replace with tankless water heaters and in-unit high-velocity small duct central heat and air (using electric baseboard for the garden unit heat), and also remove all the radiators from the building.With the furnace and water heater removed, we would like to knock down the walls dividing the current furnace room, and make one larger rear, which is the bulk of the remodeling work to be done. don't not currently have drawings or architectural plans.

My wife is at a yoga retreat in Bali and wondered why she would be getting a call like this! 

The yard is suffering because of the heat.

The costs of concrete, site work, utilities, permits, licensed tradespeople, heating systems, button-up, garages/decks, etc will blow you away.

The allure of being able to cap major expenses for an AC or Heat pump at 450$ a year plus 100$ per incident charge seems like a good way to keep your costs fairly predictable.I suppose, if you pay this thing for 10 years, and have some minor things like a dishwasher/ AC issues/ Heat pump issues and they fix it, could be a wash more or less.   

I’m in the process of locking in subcontractors for my latest project in Sparrows Point, MD and was wondering if anybody could recommend an HVAC company to install a new heat pump (or mini-split) system in a single family house.  

You did not specify electric or gas or the size of the unit by I use them often because:-For smaller units they are cheaper and easy to install-Take up very little space-Are efficientThe negatives:-May require a breaker reconfigure as the usually require 2 30amp breakers-In bigger properties with a long run say to the other side of the house, it takes a minute or 2 to heat up

Heat is natural gas.