This Winter Is 37% Warmer than 2010-11 (by Heating Degree Days)

We celebrated Groundhog Day earlier this month. Naturally, that means we held our annual juggling festival here in Atlanta, but some people associate groundhogs with their weather forecasting ability. My question this year was, How can Punxatawney Phil (the weather predicting groundhog) or General Beauregard (his Southern counterpart) say anything at all about more winter when we haven't really had a winter at all? Yes, it's been quite warm this winter, especially in comparison to last year. So I thought I'd check to see just how much warmer it's been.

First of all, looking at the number of Heating Degree Days (HDD) is a great way to compare the cold weather of one year to another. There are three nice websites where you can get the Heating Degree Days for your location:

You should definitely check them out.

Heating Degree Days are a way of looking at how much time your area has spent below a given temperature, called the baseline temperature. The most commonly used baseline here in the States is 65° F, so here's how what it means:

  • 1 minute at 64° F gets you 1 Heating Degree Minute.
  • 1 hour at 60° F would be 5 Heating Degree Hours.
  • 24 hours at 30° F accumulates 35 Heating Degree Days.

See how it works?

One way that you can use these numbers is to calculate the amount of heating your home needs. Since your heating load depends on how cold it is outside, the more Heating Degree Days you have, the more heating you have to pay for. The basic equation for this is:

 

The number of Heating Degree Days tells you the ΔT over a given time period.

So, here in Atlanta, we had a total of 3396 HDD in the 2010-11 winter. It was really cold last year, and we actually had snow three times. We normally get one little snow a year, but we even got shut down for a whole week with snow that turned to ice on the roads and then stuck around. Our 30 year average is about 3000 HDD, so last year was colder than normal.

This year however, if we look just at December and January, we find a huge difference:

 
December 2010: 891
December 2011:506


January 2011: 823
January 2012: 570

 

The 37% number in the title of this article comes from comparing the HDD of just those two months. We had 1714 HDD in those months in 2010-11 and 1076 HDD this winter. It's great for heating bills and getting outside and doing stuff here. Not so great killing bugs though.

How do your Heating Degree Days this winter compare to last winter?

 
This article was one of many that we publish in the Energy Vanguard Blog. To get them all as they're published, you can subscribe to our blog by entering your email address in the box at the top of the page.

Photo by AlicePopkorn2 from flickr.com, used under a Creative Commons license.

Views: 465

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Comment by David Meiland on February 21, 2012 at 8:02am

My perception was that we have had a warm winter, but comparing December and January this season to last, it has actually been a bit colder this season.

Comment by Edythe Moore on February 20, 2012 at 4:58pm

We are in Michigan, "the Winter Wonderland!" and my friends in Dallas Texas got more snow then Michigan this year.  I can't recall a November in Michigan where I only wore a sweater for outerwear! 

Comment by Paul Raymer on February 20, 2012 at 7:42am

From the log on my office, we are about 30% warmer this Dec + Jan than last year.  The way it's going this February, looks like it will be equally as warm.  The only measurable snow we have had here on Cape Cod was while I was away at the ASHRAE conference and my wife was left to shovel the driveway!  Our 2009 HDD were 5211, 2010 = 5403, 2011 = 4955.  I heard there is an organization for non-skiers that has been started - "Central New Yorkers for Global Warming!" 

Comment by Craig A. Lawson on February 20, 2012 at 7:11am

There's 12 months.  Here's the data taken from the KSTS station

Station: SANTA ROSA SONOMA COUNTY, CA, US   (122.81W,38.51N)
Station ID: KSTS
Month starting HDD
2/1/2009 489
3/1/2009 438
4/1/2009 357
5/1/2009 250
6/1/2009 186
7/1/2009 211
8/1/2009 179
9/1/2009 176
10/1/2009 271
11/1/2009 462
12/1/2009 652
1/1/2010 549
  4220
2/1/2010 430
3/1/2010 470
4/1/2010 416
5/1/2010 313
6/1/2010 158
7/1/2010 191
8/1/2010 208
9/1/2010 170
10/1/2010 252
11/1/2010 429
12/1/2010 481
1/1/2011 580
  4098
2/1/2011 510
3/1/2011 431
Comment by Ed Minch on February 20, 2012 at 6:59am

Craig

Is there a reason you only accounted for 11 months of each year?  That would make the 12 month totals even worse when adding January to each.

Comment by Craig A. Lawson on February 20, 2012 at 6:52am

Santa Rosa, California   

2/1/09 to 1/1/10 = 4,220 HDD

2/1/10 to 1/1/11 = 4,098 HDD

2/1/11 to 1/1/12 = 4,183 HDD    

100 year average = 3,019 HDD

 

In our local, it begs the question, "Where's the heat?"

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Mst. Fatema Aktar is now a member of Home Energy Pros
3 hours ago
Robert Leone added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Blower Door Package for Sale

Hi,I am selling my blower door with extras as a package or individually. These items are used but…See More
10 hours ago
Profile IconRobert Leone and Richard Vito joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
10 hours ago
Richard Vito joined Sean Lintow Sr's group
Thumbnail

Best Practices (Residential)

Best Building, Retrofitting, or even Auditing Practices - what are they, what should change, what…See More
18 hours ago
Richard Vito joined James Sayers's group
Thumbnail

Marketing Energy Efficiency

Sharing ideas, tools and examples of promoting energy efficiency to consumersSee More
18 hours ago
Richard Vito joined Allison A. Bailes III's group
Thumbnail

HVAC

HVAC design, Manuals J, S, T, & D, Duct leakage, Air flow, ENERGY STAR new home requirements,…See More
18 hours ago
Richard Vito joined Kyle Brown's group
Thumbnail

Wrightsoft - Manual J / Manual D

If you use Wrightsoft to calculate loads or design ducts, you likely have questions.  Get answers…See More
18 hours ago
Jim Gunshinan commented on Jim Gunshinan's blog post Energy Upgrade California—Up Close and Personal
"I had a revelation while attending Bruce Manclark's session of duct leak testing at the Energy…"
yesterday
George J. Nesbitt commented on Jim Gunshinan's blog post Energy Upgrade California—Up Close and Personal
"Blower Door; the 2007 test was a depressurization test, and the 2014 a pressurization test, which…"
yesterday
George J. Nesbitt replied to Kaushal Bharath Raju's discussion Affordability & Deep Energy Upgrade/Passive House Retrofit in Berkeley, California.
"Plan, plan, plan, plan. The 1st step to is to understand the house, how it's built, the…"
yesterday
George J. Nesbitt posted an event

High Performance Windows - A Panel of Experts at Pyramid Alehouse`

April 26, 2014 from 3pm to 5pm
Join a lively panel discussion on high performance windows. We'll cover some basics, as well as…See More
yesterday
Kaushal Bharath Raju replied to Kaushal Bharath Raju's discussion Affordability & Deep Energy Upgrade/Passive House Retrofit in Berkeley, California.
"Hi David, Thanks for pointing out Martin Holiday's article. I do not wish to engage in the…"
yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service