for us PNW folks, this year's chill seems to come @ just about the same time as last year, and the year before: tonite it's gonna drop down from 52F (11C) down to 28.4F (-2C).

House is kept @ about 68F (21C) for anything colder, my wifey will have headaches.

Fortunately, the futures market for natural gas has come down since october, so we should be ok (cost-wise) to heat the house this winter.

Q.

p.s. I started turning on the boiler this year when the fall brings the temp from 18C (64F) during evenings suddenly down to about 7C overnite (46F)...that's when the inside of the hosue gradually cools off down to about 16C, and wifey will start to complain..

It surely depends what you want the figure for. If it is for your own use when considering the use of your own heating then it might make sense to base it on the temperature at which you start your heating. If you want to compare your heating and/or climate to mine it makes more sense that we use a standard temperature.

There are many ways to use HDD data.

I was using HDD info at 'base 68F', as a reference point, so that other people could compare their own HDD situation on an "apples to apples" basis.

-AC

Cold Weather Torches Body Fat, Study Shows - weather.com
So for weight loss, it looks like around 63F is a good value.

Funny when they do studies to prove the obvious ,

Researchers found after extensive testing found that eating snacks before bedtime led to weight gain in 95% of those in the study.

We've had some more global warming here lately and I've been shutting down
the Sanyo Mini-splits when it drops below 10F.. Tonight I turned them off at 8F,
and they were still putting out pretty good heat.. But using x2 the normal power.

It's about 2F now (almost midnight) at our house and 3F just down the road.
The conditions map shows the cool air moving down from the north.
WOBURN WEATHER CENTER - New England Temperature Map
It's going to get down around zero in the morning. According to the forecast.

So, I've set the oil burner to 66F and the space heaters are at set near 66F.
It's likely we will be burning a lot of oil this month..

Wish I was in the Fl Keys..

Such studies can be useful though, or some idiot will stand up in parliament and say "There is absolutely no evidence to show ..."

Ours stays at 73 all winter and 76 all summer. No use in trying to program the thermostat, the wife is home all day and that's the temperature that makes her happy. We've disagreed over the temperature for a time and then I gave in {up?}.

This reminds me of a time when a girlfriend of mine, who had been working in South America, came up to live with me in Oregon, in the winter.

I was burning wood to heat the house, and she liked the house temperature nice and toasty warm. In fact, she'd sit close to the wood stove, in shorts and halter top, sipping ice tea.

So one day, when I was outside in the frost and near-freezing drizzle, chopping wood to support her tropical comfort, the idea came to me that she might be interested in learning a new skill.

So, I showed her where the wood pile was, and what a splitting maul was for, and how to do the work safely.

I'd have to say, that even though I preferred the way she looked in shorts and halter top, she still looked pretty good in sweater and jeans.

-AC

It got very cold for South Carolina last night @3:00 am it was 19F and dropping. We have not used natural gas heat yet. We have a surplus of power to use up or lose it March 1. Yesterday we used 100 kWh in one day. I did cover some of that with solar power that day but it was very cloudy.

I think this was my top usage day. We did charge the Chevy Volt twice for about 24 KWh and my wife cooked in the oven and did some laundry.

Before the Mini Splits we had high power usage days like this in the summer now we only have them in the winter.