https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/ Building science knowledge, HVAC design, & fun Fri, 29 Oct 2021 14:25:53 +0000 hourly 1 https://wordpress.org/?v=6.6.2 https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7688 Thu, 26 Feb 2015 18:31:34 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7688 Georg: Yes
Georg: Yes, degree days do depend on the temperature scale because Fahrenheit and Celsius degrees aren’t the same size. For each 9° F there are 5° C. Likewise, for each 9 degree days based on Fahrenheit temperatures, there are 5 Celsius degree days.

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7687 Thu, 26 Feb 2015 09:00:14 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7687 So, is the absolute value of
So, is the absolute value of an HDD (or CDD) figure different depending on which temperature scale it is based on, leaving all other parameters unchanged? In other words, if an American quotes an HDD figure to a German, will the latter understand that figure, or will it have to be converted, just like °F has to be converted to °C?

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7686 Mon, 26 Jan 2015 19:57:50 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7686 Also, building mass, which is
Also, building mass, which is really overvalued for “R-value equivalence”, DOES play a role here, as does the normal diurnal outdoor temperature swings. If you’re in constant cold, that’s different then cyclical excursions to temps below base temperature where the mass of the building can even things out. 
 
If I’m calculating for ICF or other massive constructions, I typically give a nod to my base temperature to reflect that ability of the building to temporarily even out the milder swing temperatures. 
 
I’d really love a simplified tool that allows a user to put in plug loads, building mass, design heat load, and zip code and have it run the building through a model year to give us a good estimate for DD base temperature.

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7685 Sat, 03 Jan 2015 06:52:01 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7685 It is incumbent for us to
It is incumbent for us to remember that not only are the degree days for any location variable from year to year. They are also on an upward trend. An issue that we wish was not true, but is real. 
See slide 19 on the attached link 
http://www.proctoreng.com/dnld/Proctor-DatanotDogma.pdf

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7684 Sat, 20 Dec 2014 17:28:33 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7684 Thanks for taking time to
Thanks for taking time to write this informative article during this BUSY SEASON. Many wishes for a rewarding CHRISTMAS and HAPPY NEW YEAR!

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7683 Wed, 17 Dec 2014 21:38:32 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7683 To Bob’s comment – that is
To Bob’s comment – that is why air temperature measurements (alone) are not a good measure of comfort regardless of what the Nest/Google people would have you think (that would be a different blog topic). Heating/cooling degree days are only good for comparing and measuring structure/system changes that affect energy use.

]]> https://www.energyvanguard.com/blog/the-fundamentals-of-heating-and-cooling-degree-days-part-2/#comment-7682 Wed, 17 Dec 2014 17:22:56 +0000 http://energyvanguard.flywheelsites.com/?blog_post=the-fundamentals-of-heating-and-cooling-degree-days-part-2#comment-7682 Other factors that affect
Other factors that affect base temp are 
Wind chill and Solar gain. These are particularly troublesome to nail down into efficiency calculations. If it’s morning before the sun comes up and windy my house may need heat when it’s 60f degrees outdoors. If it’s a sunny afternoon with no wind it may be 45f outdoors before I need heat. Base temp is a moving target that varies throughout the day. I’ve found 55f to be about right when doing year to year comparisons on my own house. 
 
When using the conventional 65f it threw my calculations WAY off when comparing a record cold winter to a normal winter. That’s what led me to do more investigating on base temps.  
http://homeenergypros.lbl.gov/forum/topics/how-to-determine-hdd-s-and-savings-from-furnace-upgrade

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