Tankless Electrical Water Heaters

No, they are not regulated.

For modeling purposes, on instances where I have electric tankless water heaters in the proposed, would the baseline's counterpart just be an identical water heater?  The first two rows in Table 7.8 are for electric water heaters, but they assume a storage of some volume, not tankless.

Table G3.1.1 (11) Baseline describes the baseline water heating system. It does appear that you model the same system type in the baseline as the proposed.

Section 7.4.2 makes the statement, "Equipment not listed in Table 7.8 has no minimum performance requirements".  Electric tankless is not listed. G3.1.1 (11)b references new hot water systems, which is my case, but it refers back to 7.4.2 which simply says no minimum performance requirements exist.  Since both of the above seem to point back to each other with regard to electric tankless, it's more of an unwritten rule for for systems not specified in Table 7.8 that it simply must be identical to the Proposed. Would you agree? That is not explicitly said (which would be nice), but seems to be the logical conclusion. I wish I could have a singular reference to back that up.

Also, is the SL value supposed to be the same for Proposed and Baseline? I appreciate your feedback and clarifications, Marcus!

In this case yes it would be modeled identically. 7.4.2 is a mandatory provision so this is simply saying that there is no minimum efficiency required for tankless water heaters. G3.1.1(11) Baseline says that the baseline water heating system should be the same fuel source as the proposed. The reason that tankless systems should be modeled idetically is bacause they do not have a minimum efficiency requirement. IF you want to try and show any energy savings you could try to use the exceptional calculation method.

Yes I think the SL should be the same. Again if you want to claim any savings relative to a tank-type water heater use the exceptional calculation method.

Great! Thank you very much for the guidances.

I also have a gas tank heater in the project with 96% Et. In this case, there would be savings associated with the increased efficiency over Baseline 80% Et correct?

Yes there is!

The SL has an Et term in the equation. My proposed has the 96% Et, but the baseline would be based upon 80% Et. So the SL would be a bit different in that case, resulting in savings from both the overall Et and the computed SL as well, correct? Also, the SL is based upon a 70F temperature difference between stored water and ambient; the relation will be used nontheless, even when this temperature difference is not 70F?

In 90.1-2010 Table 7.8, for gas storage water heaters, the relation for SL is .8*Et*(Q/800 + 110*V^.5). If my proposed Et is 96% and baseline is 80%, then there is savings from Et alone, and from SL since there is Et in the relation. Do I interpret that correctly?

My mistake. I looked at a User's Manual and found that the max SL does not include the .8*Et. The formatting in the chart makes it look like it's all one relation.