Degree Days

IanIanIanIanIan

Reading the Energy Forum I am a little surprised that Degree Days has not been mentioned.

This is the mechanism that professionals use to measure and predict heating (and cooling) loads for buildings.  It can be a little confusing for those of us not mathematically inclined but I have found it worth the study.  All is explained here:

https://www.degreedays.net/

so with Degree Days statements like “December 2022 was warmer than December 2021” may be given some actual numbers for your situation.

Have fun with the concept and enjoy the maths of it all working out where you are going!

Mstty

https://forums.moneysavingexpert.com/discussion/6410469/heating-on-all-night-and-degree-days

https://forums.moneysavingexpert.com/discussion/6414053/december-2022-4oc-colder-than-december-2021/p1

https://www.timeanddate.com/weather/uk/

Astria

Isn't this just outside air temperature data?

I know the heat loss for my property based on certain outside temperatures to ensure I can keep the property warm at various outside temperatures like -10c, so how does this data help?

Apodemus

Thanks for posting that link, which is interesting.  I'm more familiar with the concept of Growing Degree Days than Heating or Cooling degree days, but it is the same principle. 

It used to be recommended practice that farmers should use the figures for "T sum 200", as a guide to applying Nitrogen fertiliser.  This was calculated from soil temperatures and gave the point in spring where the soil was warm enough for grass growth to start.  The calculation was the cumulative sum of average day/night soil temperature (ignoring figures below zero) from 1st January.    Every year for about 40 years The Farmers Weekly published the map each week through the spring and you could see the country slowly warming up as the Tsum figures rose and spread from the South west up to the north and east. 

Unfortunately in some of the very mild springs that we have had, Tsum200 was reached too early, at a point when land was too wet for fertiliser applications and with risk of fertiliser run-off, so the advice and (sadly) the Farmers Weekly maps were quietly dropped. 

PeterGr

Astria said:

Isn't this just outside air temperature data?

I know the heat loss for my property based on certain outside temperatures to ensure I can keep the property warm at various outside temperatures like -10c, so how does this data help?

DD are a function of outside air temperature, a base level where a building requires no heating (or cooling) and time.  Heat loss calculations are used to size radiators and boilers, whereas DD are used to compare the energy consumption for different periods of time and deduce whether any difference is due to outside air temperature or is down to intervention by changes to control settings or improved insulation etc.

Consumption data is used to establish a mathematical relationship in the form of kWh Energy = E.rate*DD + c, and then in subsequent periods actual consumption is compared to the consumption predicted by this relationship.

Monthly DD tables for different regions used to be published (in the 1980's), but that was before PC's and the internet.

I keep a table of DD for a weather station close to where I live just to compare one year to the next.

Qyburn

PeterGr said:

Monthly DD tables for different regions used to be published (in the 1980's), but that was before PC's and the internet.

I worked in energy management in the '80s, but the bottom absolutely dropped out of the industry and everyone lost any interest in energy saving. Now after losing maybe 30 years of development people are starting to rediscover things that were used back at that time.

BUFF

I, at least, have been familiar with degree days for over a decade (basically pretty much as soon as I got interested in household energy consumption & my heating system). 
From that experience I, perhaps wrongly, assumed that once anybody got seriously interested in heating their residence they would come across the concept?