How would anyone interested calculate the loads for a tankless water heater. I am pricing a new home for a customer that has two of them( one 28kw, one 18kw). Using the optional calculation method calls for a 225 Amp service. Standard calculation method calls for 400 Amp. How do you handle it.
Tankless Water Heater
- Thread starter fido
- Start date
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cadpoint
Senior Member
- Location
- Durham, NC
fido said:
There quite a few threads here on your post subject tankless water heaters that you might search and review and get back to us with details of your the install ...
I have gotten with the POCO. There will be a charge to the homeowner as this is a new development( 5 acre tracts). haven't heard back from them yet. This is a new house 2200 +/- sq ft. all electric. Not overboard on the fancy stuff. Most load is the 2 tankless heaters and 20kw strip heat. Ran the numbers in standard calculation method ended up with 385 Amps demand. Optional method ended up with 223 amps demand. Just cautious about putting too small a service on this house. I ended up quoting the 400 Amp service. I am going to do some testing on these water heaters after install to get some real world numbers for future reference demand wise.
Thanks for the replies
Paul
Thanks for the replies
Paul
- Location
- Chapel Hill, NC
- Occupation
- Retired Electrical Contractor
With 20 KW strips and the two tankless water heaters (Are you sure of the wattage on thos water heaters--seems excessive for a small house) , I would without a doubt install a 400 amp service.
I don't have time to do the calculation but with a heat pump and all that other stuff it doesn't seem possible to use a 225 amp service.
I don't have time to do the calculation but with a heat pump and all that other stuff it doesn't seem possible to use a 225 amp service.
- Location
- Massachusetts
Dennis Alwon said:
With tankless electric water heaters the size of the home will not have much influence on the size of the heaters although it will control how many of the units are needed.
If you want a tankless to make enough hot GPM for a decent shower it will take a lot of power no matter the size of the home.
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