Friday, May 23, 2008

Remarkable Gas Savings with New Furnace

A few years ago I replaced an old gas furnace with a new, more efficient unit. The old furnace had failed, so there was no choice in the matter. This past week I captured my usage history from the web site provided by my gas provider and built this chart. The data ranges from October 2003 to the present. I replaced the 17 year old gas furnace the last week of March 2005.

It’s pretty obvious that the new unit uses less fuel. It even saves gas in the summer months most likely due to the fact that it does not have a pilot light. The plot also has a linear trend line which definitely indicates that usage has decreased. I continue to make other small adjustments to reduce consumption. For instance, I have replaced a programmable thermostat, built an attic stair insulation box and made more use of a space heater which allows me to set the thermostat lower.

The secondary axis is an inverted temperature scale and the smooth oscillating green trace represents the average temperature for each month. It’s surprising how the temperature profiles over the years follow each other so closely. There is not a whole lot of variation when averaged out over a month.

A comparison of the maximum usage of 12.3 in Feb 2005 to the maximum of 8.8 in Feb 2008 resulted in a savings of 3.5 thousand cubic feet of gas, while the average temperature was the same at 47 degrees for each of those months.

I am thrilled to be using less gas, but as you might expect, the bottom line has not changed due to rate increases. My total gas bill for the past year is remarkably similar to that in 2005.


  1. That is a remarkable savings on your gas bill, I've been doing some research on heating systems for my home and Im not sure wether the gas furnace or a heat pump would be better, I've heard that a heat pump is more efficient and I've been reading through some heat pump reviews for a better understanding of how the two operate. Great savings though!

  2. I'am thrilled to use this new furnace. The gas savings are remarkable and will truly help save a lot of cash.