A Conditional formula that adds values in column but ignores other values

I have a spreadsheet that lists the power consumption of various electrical devices.

Column A has the name of the device, Column B lists the energy in Watts and Column C has a Yes/No note on whether the item is on 24/7 or not.
eg: Modem, TV (stand-by mode), printer, clock would all be on 24/7, whilst the kettle, TV (watching TV), dishwasher, cooker would only be on occasionally.

I want to be able to add up all those values in Column B that are on 24/7 so I know the base energy usage. So if Cell C1 is YES, then the value in Cell B1 is added. If Cell C2 is NO (or blank) then the value in Cell B2 is ignored.

The intention is that the answer at the bottom of column B only includes those items which are on 24/7.

Hope I’ve explained myself clearly.

I can send a mock-up if this helps.

Welcome to the forum

You can use SUMIF

=SUMIF(C1:C100,"Yes",B1:B100)

Thanks Jonmo1 & Wayne. Not only for your answers but the incredible quick response.

You're welcome.