I have been eager to get my natural gas bills to try and determine how well my new furnace is working. It should be a lot more efficient than the old one, plus insulation was added to the attic, the ducts are much more airtight, and a lot of work was done sealing air leaks. But there are also some things going on that make comparisons with previous years more difficult. One is it has been really cold this winter. The other is that Eric is here, so I have changed the thermostat setting and am keeping the house at the same temperature all the time now instead of turning the heat down during the day when I’m at work and at night when I’m asleep.
Right now my natural gas provider is Scana. I have been with them for about 5 months. On their website you can download your bill with the gas usage and cost on it. One thing that happens is one month might have a couple of more or fewer days in it due to the length of the month or where weekends fall for the billing cycle. But the other big variable is the weather. Some Decembers are just colder than others. But that’s a really hard thing to determine. But Scana has some information in their usage section that gives you the average temperature during the billing cycle as well as the number of days where the temperature goes below 30 degrees. I don’t know that I could use those numbers to perfectly determine the right gas usage, but it would help to know that the reason I am using more gas is that it has been significantly colder or warmer than last year. The problem is I haven’t been with Scana for long enough to do a comparison year-to-year (and may not be with them next year).
I have looked on the internet before for past weather information, but I have had a hard time finding it. Nobody really cares about past weather, just present weather and future weather. But I looked again and found that Weather Underground lets you look up historical weather information. That’s maybe not that surprising from Weather Underground, since their site has a tendency to bombard you with tons of data from dozens of different weather stations in your area. The data they have for me comes from Peachtree Dekalb airport, so it should be pretty consistent. I was able to pull up information for an entire year and then export that to a comma-delimited file that I could then import into a spreadsheet. Then it wasn’t too hard to come up with an average temperature for the month and a number of days below 30 degrees (Scana lets you pick any temperature you want, so I set the spreadsheet up the same way). Just comparing December 2013 to December 2012, it was definitely colder this year, with an average temperature of 46.3 in 2013 compared to 48.6 in 2012. In December 2013, it got below 30 degrees on 10 days vs. only 4 days for December 2012. 2010 was significantly colder, but I think the data is wrong because it shows the low on December 12 as -2, which seems very unlikely. If I look for data in a nearby zip code, the low that day was 26, but overall it was a pretty cold month with 16 days below 30 and my gas usage was pretty high then, so maybe the rest of the days are right.
To really get it right, I would need to look at the billing period which tends to go from somewhere around the middle of the month. The key thing is having the data, and I’m not sure I want to go in and enter all of the billing dates (though I keep track of those).