3 tank less water heaters dwelling

[chris kennedy]

I'm not up on 220 dwelling load calcs. Question just came in from shop about if a demand factor can be applied to the thread title.
Going to review 220 now just look for help from you people that deal with dwelling units for a living.

Thanks

 

[chris kennedy]

Looks like 220.53 would only allow a demand factor if we had 4.

 

[ActionDave]

Might be more cost effective to add a fourth one to the house.

 

[LarryFine]

The neighbors would just love the flickering lights.

 

[suemarkp]

The optional calculation will count these (and most everything else) at 40% nameplate. But 3 electric tankless water heaters is a challenge for any residential service to deal with (and most take 2 or 3 double pole breakers per tankless). You'll most likely be needing a 400A service. These should really be gas fired if you want tankless water heaters. Or put in one central tankless feeding a few smaller (20 to 40 gallon) electric tank type units close to each shower or bathtub.