DegreeDays.Net
.) One assumption is that the kWh/HDD figure should be roughly constant, at least when there is space heat demand. The kWh/d figure often won't drop to zero even when there's no heat demand, such as in summer, where the same energy or fuel is used for other things such as cooking or DHW (Domestic Hot Water) as it often is in the UK.
I plotted 16WW daily gas consumption against HDD (with 12°C base) for 2016 up to the end of June 2020. Although it's messy, I think it's true. Heat demand (kWh) rises massively mid-winter as you'd expect, but the kWh/HDD shape seems much flatter, which is what I wanted to check. Note that we generally only have the heating on November to March.
The pattern recognition built into our brains is pretty good. For those of you looking at this episode's page and Show Notes you can see if you agree with my interpretation or not!
For 16WW kWh/HDD is now around 2.5. Before conserving it was over 4.
For 2019, the metrics were 2.3kWh/HDD and a baseload of 2.7kWh/d. Those are about right, extracted from our messy real-world data! The years 2016 through to 2019 show similar values.
For 2020, for the first six months including a record-warm spring and lockdown, the figures are 1.7kWh/HDD and a baseload of 4.8kWh/d. The latter up (and the former down) likely due to unusually high occupancy.
(As of this episode only half the data for 2020 exists, but the data set and graphs for it should update as more comes in.)
Have a look, in the Show Notes, to see all the graphs and the raw data, and see what you think.
I'd like to go back and do the same for previous years, though instead of daily data from Loop for gas demand, I have manual meter readings already captured electronically at about weekly cadence. I have more detail that I could transcribe from paper records if needed.
Though I didn't audify any numbers this time, I didn't want to leave noiselessly.
Over the last couple of days I've been enjoying the field recordings [then hosted at, gone by 2023] at Cathartic Audio. So I made another of my own, a 'daytime' 16WW capture to go with previous dawn and dusk.
Here's a little of it, with birds and cars and DIY, oh my!
[suburban noises and birds chirping]
The full raw track is available from the Show Notes.
And since you asked, that (mystery) repository revision number as of preparing these words is 35359, up 675 from the last statscast, so just over 20 revisions per day.
There's more on my "Earth Notes" Web site at Earth.Org.UK
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Year | Daily data | By date | kWh/HDD |
---|---|---|---|
2016 | .csv | ![]() | ![]() |
2017 | .csv | ![]() | ![]() |
2018 | .csv | ![]() | ![]() |
2019 | .csv | ![]() | ![]() |
2020 | .csv | ![]() | ![]() |
The full ambient raw track recorded from the window by my desk (Blue Yeti, 48ksps, stereo, omnidirectional):
Playback requires an Internet connection.