Every time I make this calculation, the gas beats the electric. We
have had recent price hikes in both gas and electric. If you can
easily install the gas dryer, that would be the better of the two.
With a scientific background, I can't see how altitude can make any
difference (but I'd be curious to read the reason!). I have found
that gas dryers cost more initially, but will save money in the long
At high altitudes, the air is thinner, so you are more likely to have
problems with incomplete combustion. You have to lower the gas
pressure or change the orifice size to reduce the gas input. A gas
dryer will dry slower at high altitude because the heat input is lower.
That does not make it less efficient, just slower. Being slower with
a lower heat input, it will use less gas per hour than at sea level.
The total amount of gas used to dry a load of clothes should be about
the same. As was pointed out, burning gas in air produces water vapor,
so the air leaving the flame is wetter, but because the temperature is
higher, the RELATIVE HUMIDITY is lower, even though there is more
moisture in the air. That is because air at high temperatures can hold
more moisture than air at low temperatures.