So finally everything is in place: * mvhr unit up and running * terminals and valves installed * house pretty much as air tight as it will ever be * Anemometer Tesla 405 borrowed with extra large valve covers - big thanks @JSHarris   So to work on balancing. Any tips on how best to approach this? * Screw everything shut and open on longest extract one first get its flow rate right and then open another set it and go back to first readjust? * Set all valves