Is this a job for SUMPRODUCT? Or is it easier?

[Bob Phillips]

OK. I used (Sheet Names Changed, Sorry)

=SUMPRODUCT((ISNUMBER('Cold Difference'!$1:$4))*('Cold Difference'!$1:$4<=Charts!A1)*(('Cooling Type'!$A$1:$A$4="C")+('Cooling Type'!$A$1:$A$4="K")))

and it seems to work. Sorry..."C" or "K" would be found in column "A" not "B"

Mine is neater! But that is sophisticated SP for someone who supposedly doesn't understand it.

Oops. I meant (Column A is a "C" or "K") AND (Column B is a "T")

for which I used

=SUMPRODUCT((ISNUMBER('Cold Difference'!$1:$4))*('Cold Difference'!$1:$4<=Charts!A1)*(('Cooling Type'!$A$1:$A$4="C")*('Cooling Type'!$B$1:$B$4="T")))

which also works fine.

Dont' you mean

=SUMPRODUCT((ISNUMBER('Cold Difference'!$A$1:$IV$4))*('Cold Difference'!$A$1:$IV$4<=Charts!A1)
*(ISNUMBER(MATCH('Cooling Type'!$A$1:$A$4,{"C","K"},0)))*('Cooling Type'!$B$1:$B$4="T"))