"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.

Once you've got that figured out move on to your car---must be a way to
reduce the gas flow so that the car will run slower no matter how hard you
step on the gas pedal. You'll get where you're going, will take longer and
you will save on fuel. At least, if done right, (like putting a wooden
block under the gas pedal) the engine won't blow up---can't say the same
for your furnace.
MLD