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jmen24 · 05-06-2009, 08:44 AM

I am talking about energy consumption to make the same amount of water. Your tankless has an output rating of GPM, you take your GPM output and convert to btu's used to heat your output GPM to get the overall efficiency of your application.
If you read my post completely, I stated that it all depends on usage and energy consumption, not everyone is going to demand the same amount of water.
For an example, in a recently completed project, a 6'x5' performance shower was added in an existing system. Either way an upgrade was needed as the 12 shower heads and body sprays used 11GPM. That required the use of 380gal of storage to satisfy demand. A tankless unit would not even come close to providing the amount of GPM's needed to satisfy demand even if it was solely for that shower, not to mention it would tax the well pump for supply, because that runs the whole time as well.

Hopefully that illustrates my point a little better.

05-06-2009, 08:44 AM	#6
jmen24 Senior Member Join Date: Feb 2009 Posts: 1,139 Thanks: 223 Thanked 319 Times in 181 Posts	Energy Consumption, not hot water supply I am talking about energy consumption to make the same amount of water. Your tankless has an output rating of GPM, you take your GPM output and convert to btu's used to heat your output GPM to get the overall efficiency of your application. If you read my post completely, I stated that it all depends on usage and energy consumption, not everyone is going to demand the same amount of water. For an example, in a recently completed project, a 6'x5' performance shower was added in an existing system. Either way an upgrade was needed as the 12 shower heads and body sprays used 11GPM. That required the use of 380gal of storage to satisfy demand. A tankless unit would not even come close to providing the amount of GPM's needed to satisfy demand even if it was solely for that shower, not to mention it would tax the well pump for supply, because that runs the whole time as well. Hopefully that illustrates my point a little better.