It sounds maybe naive but I was thinking that if we almost all turn down our heating system by ~3° Celsius (compared to our current settings) we could potentially save gas consumption that can be better used for other purposes. What do you think?
It's not naive. Going to "pure" building science (I studied this in uni) the formula for the building heat loss is Q=U.A.dT where dT is the temperature difference between indoors and the outdoors.
If you assume that outdoors is 5°C on average in year, and indoors is 21°C, dT is 16. reducing the indoor temp to 18°C puts the dT at 13.
Since everything else stays the same, you'd expect a 23% decrease in heat loss (Q). And that much less energy need to be replenished.
In the real world buildings are more complicated than that. Also you may risk giving more people diseases and reduce cognitive abilities when things get cold. So perhaps also tell the public to dress warmer and drink more hot fluids.
Many EU gas boilers are set too high, such that the boilers don't operate in condensing mode. You could save 6-8% gas by doing this: https://www.theheatinghub.co.uk/articles/turn-down-the-boile...
Octopus Energy has some further tips: https://octopus.energy/blog/winter-workout-gas-saving-tips/
Older houses sometimes still can benefit from insulation improvements.
So go in this order:
1. effective insulation
2. conscientious and smart use of energy and avoidance of very inefficient heating systems. avoid heating large areas when they don't really need to be at very warm temperatures. (careful though to avoid damp cold range of temperatures where wood rot and permanent damage to homes will happen). Avoid unburnt natural gas, eg in badly maintained or cheap cooktops. The ideal household kitchen has ~ 4 gas burners, and one or two induction burners flush with the counter, eg https://www.amazon.com/Countertop-Portable-Induction-170-Min... This minimizes unlit gas for those very short heating needs in the kitchen.
3. think about upgrading to very efficient systems. These most promising could be (depending on your area and scale of heating needs):
-- electric-heat cogeneration
-- heat pumps that use the large volume of ground underneath the basement as geothermal heat-mass reservoir. Heat the ground mass during the summer to provide AC, and squirrel away the cold thermal mass during late fall and late winter+spring.
So here's my advice for people:
1. Start today! Don't wait to see what happens in Ukraine. Lower your temperature by 1 degree right now. Just do it. 1 little degree isn't a big deal. Let your body acclimate to that. It'll happen on its own - our bodies constantly adjust to different temperatures throughout the year. Know that a temperature barely lower than you're used to won't give you hypothermia. It's not a threat to you. It's just a slightly different temperature so embrace it. Welcome the change, mentally choosing it. Once you're comfortable, lower the temperature again. Rinse and repeat. If you do this, you'll look back and be shocked at how you once thought a homeostasis temperature was necessary (or even desirable).
2. Eventually you'll feel the need for extra heating. The most efficient ways are directly heating the body through appropriate clothing and direct heat sources. For clothing, if you're cold, just add more. For direct heat, use a hot water bottle. You can also get an electric bed mattress pad. A heated mattress pad is amazing.
3. Warm food and drink: in summer, drink cold things. In winter, drink warm things. Eat warm foods like porridge (oatmeal/grits/cream of wheat/etc.), soup/stew, etc. When drinking, hold the hot mug in your hand. When eating, hold the hot bowl in your hand.
3. Water conservation - a lot of the water we use has been heated, for showers, washing hands, etc. Efficient showerheads and faucet aerators are CHEAP! Some of them have their usage etched into the side, if not, you can measure its flow rate with a measuring cup and a stopwatch. Once you know how much it uses, look into upgrades. When showering, turn the water on, get wet. Turn off the water. Soap your whole body, then wash the soap off. Now you're almost done with ~45 seconds of water use. It's easier in summer, but I'm now doing this in winter also.
Those are the basics and you'll get better with time. Eventually you'll be able to see heat like Dr. Manhattan sees atoms. You'll just see it everywhere, how it moves in and out of the system, and how you can harness and hold on to it, using it multiple times before it's gone.
The real question then is how can you insulate every place in your country better.
The above is a complex question. There is the supply chain of insulation, contractors to do the work, and how to pay for it all. Still it is worth looking at.
The only risk is you might not want to go back home for spring.
As such, Australians tend to wear more clothing indoors during the winter months, including hats and sometimes even gloves. Electric blankets and hot water bottles tend to be used in bedrooms. Doors between rooms are kept closed, and only rooms that have people in them are heated, and only while people are in them.
So yes, if people in the EU were willing to accept living like this in the winter, they could save a lot of energy. Similarly, in the summer, most Australian houses only cool a single room, and even at that set the AC to around 27 degrees. If people in the EU lived like Australians, they could most likely survive without Russian gas.
To be honest I think this is the only way people in the UK are going to survive this year with energy costs literally doubling. Half the population can barely afford energy as it is.
For example, if other sources of gas are twice as expensive, then Europe might want to import half as much from alternative suppliers as it does from Russia currently. If, on the other hand, other sources are only 10% more expensive, then reducing consumption by about 10% would produce an economically neutral result. (The only difference would be that people would have X amount less thermal energy, and would be Y degrees colder on average as a result).
Sadly there are a lot of scammers out there, but the cost has dropped a lot, so many people/groups could buy one, or rent one of the costly ones for a week and test all your houses. Works best on a cold night where the heat loss shows up well and the sun does not hinder reading. There are also apps for android and ios phone that let you record data. There are also FLIR plugins etc via Aliexpress etc.
https://www.aliexpress.com/wholesale?catId=0&initiative_id=S...
At some of the larger (LA, SF etc) swapmeets there are importers who sell them, so you can look-see in advance
https://energysavingtrust.org.uk/energy-at-home/
They usually recommend turning down the thermostat in rooms you aren't using, and setting a timer to fit your schedule but there's a bunch of low hanging fruit that will make your home cosier, save you money, help save the planet and annoy fossil fuel oligarchs, all without any cost to yourself except using this media coverage to spur you into action.
One that they might not list, but which is interestingly geeky and so might appeal to HN, is short term rental of infra red camera to find where homes are leaking heat (best done during cold weather).
Energy consumption does not depend ONLY by the target temp but ALSO by the external temp, or the Δt between them, the level of insulation of your house, how airtight (and eventually with what kind of VMC you have) etc even approximated answers can't be much meaningful.
What I can testify having switched from a "classic" (low insulation, no good vent etc) home to a new "class A" (french BBC to be more precise) one is that insulation, ventilation, good passive heating (windows on south, well exposed to the low winter Sun, but covered for the high summer Sun) does work enormously well. Or, the "Green New Deal" do have some tangible basis, unfortunately it's not much practical in most of the EU, at least in cities and in general in dense area, to rebuild anything accordingly, especially in a short term.
If you want to save money and have a better life, my real suggestion is: flee the city, looking for a home you can afford, one in a reasonably served place and do your best to telework. You like it or not that's the direction we heading, so the better you can get in this direction the batter you'll get paid off in the future... Other "emergency gimmick" do not really work, if they it's too little for too much effort, or they are simple raw cuts like "to save money do not go on holidays" witch might work in some short term terms, but are not much sustainable in the long run...
One thing I have found is of course heat rises. I put a fan on the floor pointed at 45 degrees toward the ceiling and suddenly my place is warm with the same heating settings. I've done this at the last 4 places I've lived and the difference is striking. One place even used those high wall mounted air-conditioning + heater that blow the air out but it wasn't enough without the extra fan for circulation.
If you want to save energy, insulate or move somewhere warmer
Any one-size-fits-all policy that makes a quarter or whatever of the population uncomfortable, is a non-starter.
E.g. we keep our house at ~15ºC. So 12ºC / 54ºF would be really pushing it.