Who is right?

The subject is the thermostat and blocking off little used sections of the house.
I have been a maniac about the utility bills.
I have learned that keeping doors closed or hanging curtians to block off the least used parts of the house, like the bathroom, the doorway to upstairs where there were 2 beds and a bath, and the master bedroom down stairs kept costs down.
This way, only the living room, where the sensor is located, and the kitchen stay at the temp you’ve set. It has kept my bills manageable.
Rick, who has HVAC experience disagrees with this vehemently.
However he never sees the bill…he actively avoided seeing them!
He never physically paid any bills.
Per Rick the whole house needs to be wide open for the heater / AC to work “efficiently.”
My stance was that the entire house was well above freezing because some heat reached even the blocked off ones. The blocked off ones were simply cooler than the living areas.
But the bills are correspondingly higher. We had arguments about this. I especially got angry about the bedroom because we had a heated waterbed!
He left for 7 weeks once, in the middle of winter, to care for his dad. It was in Dec / Jan. Historically the coldest days of the year.
So for 7 weeks I did it my way. This included blocking off the wood fireplace we had.
The bill for that time period was $169.00. That was, on average, $100 LESS than our usual bills for that time period.
So who was right?