First time posting here, but I've learned a lot lurking in the background so far. Now it is my turn for some questions!...

Looks like I'll be needing to replace my old and sclerotic galvanized pipes with something new. I had a shut-off valve added to a basement toilet last week and the water pressure has just never recovered (even after cleaning screens, etc.). The house is from 1952....and I would put money on the galvanized being original. So, I think it's safe to say the galvanized has served its useful life...and then some!

I'm pretty set on PEX of some sort (intrigued by the new fitting system that is starting to sell), largely because I can do some of it myself and it's (comparatively) easy to work with. I've got a plumber in town who is quite good (all the other tradespeople use him, for instance), and he is totally open to me paying him for design and consulting assistance at his hourly rate. So, this would be a DIY project, but not a complete do-it-myself type of thing. The plumbed part of my house is small (kitchen with 1 faucet that shares supply with a high-efficiency dishwasher; single toilet in basement; bathroom w/ 1 shower/tub, toilet and 1 faucet and, immediately beneath it in the basement, HE washer and another faucet; oh, and two hose bibs) and about 99% of the system is easily accessible and totally visible from the basement.

My question: is there some reason I should not just ditch my fairly mediocre (and probably 12 years old) gas-fired tank water heater AND replace it with ONLY point-of-use, electric tankless unit? I ask for a couple reasons. The big one is that my water heater is basically in the farthest corner of the basement away from everything needing hot water. So, the cold supply and hot supply have to run the full length of the house to service my kitchen (which is literally right above the service line for the house). Secondly my other two hot water areas (the bathroom as well as the laundry area) are stacked on top of each other as well. Finally, mounting and connecting (the plumbing part) an electric tankless doesn't worry me too much (they are small), and I would pay an electrician to hook them up (and I believe I have the needed unused circuits to give them enough juice).

The appeal here as a DIY repiping of the whole house is that I would massively cut down on the number of water lines running around under the house. I would use a small, under counter heater in the kitchen and a mid-size heater in the basement for the basement/bath region.

Does this seem crazy? A bad idea? Any suggestions?

Many thanks!