I'm having trouble interpreting Table 7.8 in 90.1-2007. The way the performance requirements are listed is confusing, especially for gas water heaters, but I'll get to that in a bit. For electric water heaters it reads: =12 KW, Resistance >/= 20 gal. Is that just saying it's an electric resistance water hear and if it's at least 20 gallons the following performance requirement applies, but if it's less than 20 gallons, there is no required performance?

Then it reads: "0.93-0.00132V EF" Am I correct in interpreting that as: "minimum required EF=0.93-0.00132V"?

Then if the electric water heater is >12 KW, it reads: "20+35 square root of V" and then SL, Btu/h on the next line. So that should read as: Standby Loss=20+35*square root of V"?

Going down to a gas storage water heater >75,000 Btu/h input, it reads:
80%Et(Q/800+110*square root of V)

Is that saying the Standby Loss = 0.80 x Thermal Efficiency x (Gas Input / 800 + 110 x square root of Volume)? Or is it saying the thermal efficiency must be at least 80% and then Standby Loss = actual rated efficiency x (Q/800 + 110 x square root of V)?

Also for any given water heater in that table, only a Standby Loss or EF is regulated, but not both. So if they dictate the EF, they don't care how good or bad the SL is and if they dictate the SL, they don't care how good or bad the EF is? So in documenting water heaters for Tables 1.4, you only list EF or SL depending on the category of water heater, but not both?

If I have a 100 gallon gas fired storage water heater with 199,000 Btuh input, what is the required rating? What do I need to list in Tables 1.4 for both the baseline and proposed case?

Hopefully someone can clear this up for me. Thanks.