[mctabish]

We are finishing up a new home build and are looking for a solution for our needs.
We have been planning on a tankless water heater since conception. My contractor was ordering and somehow, the energy calcs for the heater was not included by our architect!
Our home does not have any gas, so Electric is the way we have to go. I may be able to add solar supplement down the road, but currently is not planned.
We have 320 amp is 400 amp @ 80% rated main panel feeding into 2 sub panels of 200 amp each. One for the house and one for the connected wood shop.
Hot water demands are for bathing:
3 showers (morning use mostly) two may typically be used at the same time, the third is in the shop and planned usage is rarely
1 85 gal tub used nightly
laundry about 8 loads a week.

Our "home" circuit panel is apparently fully used, so it seems we will need to be using power from the shop sub panel.
I don't want breakers to be popped every time I run my lathe, shaper (2-3hp motors), saw(5hp motor) etc.

We also dont want to run out of hot water while taking shower or filling the tub. Tub and showers will rarely be used at the same time, sometime 1 shower maybe ran when filling tub.

With the available power, and our desire for continuous (or appearing to be) hot water, what system(s) would be best? I have about 3k if needed for the heater system, so if need be combining 2 heaters, that would be OK. MFG & models would really be helpful!

As a side note, we are TRYING to meet LEED for Homes, but comfort may dictate otherwise.

We do have 11.4 kW Solar panels, but it is my understanding that these should not be used in the demand calcs.

Thanks! Bruce

 

[Bud9051]

Hi Bruce, I'm not a good one for recommending your heater but wanted to comment. You say "TRYING to meet LEED for Homes" yet your description for hot water needs and use seem to be miles away from that goal.

Leed implies conservation, so what are you and yours doing personally to conserve.

I apologize for my perspective, I'm a retired energy auditor, as I have always looked for ways to use less. Adjusting to the new world where an acre of solar panels can support a lavish "home energy" style is proving difficult for me.

Bud

 

[joecaption]

Why not consider LP?
They could even install a underground tank for a better look.
Faster recovery, far cheaper to run then electric.

 

[rjniles]

Hybrid electric 75 gallon water heater?

 

[mctabish]

Bud9051, you are correct!

Water is being captured in several ways. All rain water is captured to 20k tanks for storage for irrigation (and fire control), gray water is also captured and used daily for irrigation. Non permeable surfaces are also captured. We have 2.5 acre and have left most of the property native. We will have fruit trees/plants and veggies.
I need the tub due to a back injury.
We have spray foam insulation. Heating is provided by a heat pump and radiant heat. We are using solar with plans to add more.
We do want to live comfortably, but where we take, we try to replenish. We are trying to make what we DO use, go as far as possible.
A/C is seer 18.5, Merv 15

Title 24 calcs are 33.7 above Title 24, not including input from solar (as is standard). This was including a Stiebel Eltron Tempra 29 Plus 28.8 kW , but did not account for the circuit load on the breakers.

The shop is my livelihood.

Our efforts HAVE been there, and HOPEFULLY we will meet the goal. We have been paying LOTS for all of the adjustments to meet the goals and we have hired a LEED certifier and have been working with him throughout the project, so we are (were??) all on goal to at least be certified. I WAS shooting for Platinum, but we cannot make that, so we will have to settle for between certified and gold.

 

[Bud9051]

Thanks Bruce,
I was feeling a bit guilty about poking you in the ribs, but after reading your reply I'm glad I did. Really nice project and if you can, fill us in when it is done.

CA I assume?

Bud