"JohnR66" wrote in message
...
I heard that adjusting the gas valve on my standard natural gas furnace
will make it more efficient.
By partially closing the gas valve reduces the flame. Although the furnace
would run longer, the flue temp is reduced meaning lower heat loss and
improvement in efficiency.

An analogy is like driving a car the same distance once fast and once
slow. When driving slower, it obviously will take longer, the engine is on
longer, yet fuel usage is less.

I have no way to verify if this is BS or not.



Don't go fiddling with your furnace. If you want it at maximum efficiency
have a pro come in and clean the unit. Make sure that there is enough fresh
air coming into the furnace area for good combustion and for air flow up the
chimney.