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Comment by abeppu | Hacker News Reader

> For now, the concrete supercapacitor can store a little under 300 watt-hours per cubic metre – enough to power a 10-watt LED lightbulb for 30 hours.

> The power output "may seem low compared to conventional batteries, [but] a foundation with 30-40 cubic metres (1,060-1,410 cubic feet) of concrete could be sufficient to meet the daily energy needs of a residential house", says Stefaniuk.

This made me suspicious, because it sounded too low. But it turns out it's true ... for an average British home that's heavily dependent on gas.

40 m^3 * 300 watt-hours/m^3 = 12 kwh. I.e. 500 watts for a whole day.

Apparently the average American residential electricity use is 10,791 kwh/year, which is ~1,231 watts, whereas the average British home is only 2,700 kwh/year which is ~308 watts. I had no idea that the difference was so large.

https://www.eia.gov/tools/faqs/faq.php?id=97&t=3

https://www.britishgas.co.uk/energy/guides/average-bill.html

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I'm saying this with no data, but could it be because energy is just cheaper in the States? I have been using considerably less electricity since moving to NYC, since the price-per-KWh is about double what my costs were when I lived in Texas.

Also, I'd be curious how much of this could be due to electric car usage increasing?

This of course is anecdata, but I think a large percentage of it might come down to the fact that UK houses don't seem to run AC nearly as much. I spent two weeks in York a few years ago, during an extremely hot summer, and I was missing my AC very very much.

The big differences are:

  * UK requires appliances to be eco friendly - that means for most appliances they only take a quarter of the energy to do the same job.   Dishwasher/washing machine/etc.

  * UK housing has really high insulation requirements for new builds.   Your body heat will keep it warm most of the year.  They are starting to require retrofits for old buildings too.

  * Widespread use of LED lighting and expensive electricity

  * Smaller houses - less rooms etc.

  * Tumble driers aren't widespread (big energy user).

  * Electric water heating is rare (most houses use gas or oil).

  * Air conditioning isn't widespread, despite the climate kinda needing it in the middle of summer.

UK climate "needs" AC for 1-2 months, one summer in three.

And a fair chunk of that is the summer holiday season, when a lot of people won't be home anyway.

It is possible to mis-design houses and apartments to need it more than that (extreme sun traps essentially); schools/offices and public transport are a different case because of the number of human bodies in a small space.

But our homes need A/C so rarely that it's not worth it, same as most people don't have winter tyres or snow chains, or even know how to fit them. Materially significant amounts of snow for a few days one winter in three, unless you live in Scotland or the Pennines.

Having living spaces too hot has a substantial effect on productivity. Bad sleep, lethargy, etc.

As a government, it's probably a good move to encourage installation of AC in your citizens homes even if it only gets used a couple of days a year simply for the productivity benefits.

Unfortunately, current UK policies on Heat Pumps specifically discourage installation of AC (you become ineligible for various grants if your heat pump system has a valve to allow use as an AC system).

Houses rarely need AC - we usually only get a few hot days in a row, with time for houses to cool down in between hot periods. It is also usually possible to get airflow through a house, and cool things down enough.

Different story for badly built apartments, though. We used to live in a 1950s apartment, top floor with a flat roof. It reached 38C inside, when outside was 36C, and then wouldn't cool down at all during the night. It was unbearable, and we moved out!

Yep, definitely possible to design and build unpleasant sun traps! But also mostly possible (even for curtain-wall apartments) to avoid it with good design.

Not much help if you buy an existing place whose builders didn't take hot summers into account though!

These days its practically every summer tbh :P The last two have been super bad for me, as my apartment is south facing and doesn't have any AC. I'm not looking forward to this summer at all haha

If you install heat pumps, which are the most efficient single-home way to heat a house, then you get AC for free.

Indeed, I think price of electricity but also climate explains the large difference between UK and US air conditioning usage.

Many people forget that London (UK) has about the same latitude as Vancouver (Canada).

Indeed, and similar mild, rainy maritime climate.

> UK housing has really high insulation requirements for new builds. Your body heat will keep it warm most of the year. They are starting to require retrofits for old buildings too.

UK housing is mostly quite old - an average age of 50 years or so. Modern insulation requirements only became law in the last 20 years. Most houses aren't particularly well insulated - and most houses haven't had much retrofit work done. The UK is really far behind most of Northern Europe in this regard.

I think the rest of your reasons are valid. Average floor area is probably half that of a US house. Domestic air conditioning is almost unheard of. Almost everyone heats with natural gas.

Heating is a huge part of energy demand - around 25% of UK total energy goes into space heating - so if you're not doing that via electricity then average energy consumption per house will be much lower.

I'd agree with the article authors figures. I have a small family home in the UK and use about 2000 KWh a year electric only. I have gas heating and water.

Electricity cost is currently running at about 28p/KWh. I presume that's a lot more than the US. Electric heating is indeed rarer because gas is about 1/3 of the cost.

I'm thinking your points about air conditioning is likely the major difference combined with the average US home being larger so more space to air-con. Few UK homes have air conditioners (offices do) as it doesn't usually get hot enough. Although this has started to change in the last few years and I'm seeing them occasionally popping up now on neighbours houses. I wouldn't have needed one this year at all so far. Last year, maybe for one week. I was thinking about it but by the time you've looked into organising something the heat has gone and you forget about it until next year. There is a push to move to heat pump heating instead of gas and those units often can do air-con as a byproduct so that may be a driver for change.

Tumble driers are easily available and definitely widespread in the UK. The lack of tumbler driers is a bizarre myth I see again and again on lists of differences between the US and UK. I have no idea how the authors of these lists come to this conclusion. The only idea I have is maybe people from the US who come to the UK rent a furnished house and the landlord cheaps out and decides not to supply one. I do have one and it runs to about 2KWh a load maybe? I don't think that would explain the difference in any case.

> Tumble driers aren't widespread (big energy user).

My 20 year old drier uses about twice amount of kwh as my 7 year old dishwasher (on actual clean mode, not "eco: everything is still dirty and you should do it by hand mode"). I also use it far less, so on average they are about the same.

A lot of the USA also uses electric for the stove, oven and all household heating.

So does the UK. Everywhere I've lived in the UK had electric stoves; everywhere I've lived in the USA had gas stoves. I'd be interested to see stats if they exist.

Also in the USA you see gas-fired tumble dryers, which you never see in the UK, probably due to 240V all round.

A lot of that doesnt apply to old dwellings does it?

I recall in my great grandparents old terrace house, the kitchen was set behind the neighbors fireplace. The only rational place for the fridge stand effectively copped 50-80 degrees from the neighbors fire, just radiating from the brick. This lead to the fridge running constantly and having an extremely short lifespan (and sometimes not functioning at all)

That said because it was old everything was air dried.

that sounds like it has got to be an outlying situation though, and things like this tend to work on population averages.

The UK has a ton of old dwellings. Like, a three century old home isn't even a local landmark. It's just a house.

They have of course been retrofitted with electricity and plumbing and gas and modern insulation (usually), but exactly what you get depends on how recently it's been renovated. And "mid 20th century" is a very common answer.

I had a look at their home town on google maps, and it looked like 1/2 to 1/3 of the town was still made up of old terrace houses. I imagine it would be tricky to selectively demolish them.

Not really, the U.K. has some of the oldest housing stock in the world. For e.g. my house is pretty typical, built in 1912, it has a double skin wall of bricks but with no cavity. It has three original fireplaces which are all very draughty. I have timber sash windows, and though I recently got double glazing my neighbours on either side do not have it.

Buy a "chimney sheep". Made a huge difference to me.

Your body heat will keep warm is a stretch - not my idea of warm anyway 24C - maybe 16C which is chilly for most.

New builds require Roofs: 0.11 W/m²K. Walls: 0.18 W/m²K. Floors: 0.13 W/m²K. Assume 2024 houses are 7mx7mx5m high and terraced.

So you have 70m² of wall, 49m² of roof and floor. Total 24.6 W/K. So, with the average UK electricity consumption (300 watts), plus the body heat of 3 people (300 watts) you have 600 watts of heating, which should keep that building 25 deg C above the outdoor temperature.

The UK in winter normally averages about 5C, so you'd have an indoor temperature of 30C - plenty toasty.

Obviously many buildings don't meet the required standards, people aren't home all day, there are air leaks, etc. But, for most buildings, heating is still not required most of the time.

A free standing house at only 49 m^2? Is that typical in the UK? The US average size for single family homes was triple that back in the 1970’s. Today it’s more like 5 times that size.

2 floors high - so 100 m^2 of living space.

Yes, it's small, but new houses are mostly very small because they try to be 'affordable'.

Most people with lots of money buy an older house which is bigger, sometimes knocking down and rebuilding the same house if you want to modernize (in many areas you have to rebuild something the same size, shape and appearance).

Some quick checking:

Average (well, median) US house size: 2000 ft^2

Average UK house size: 68 m^2 = 740 ft^2

That makes for a very, very different HVAC bill.

Numbers vary a lot by source but the relationship (2x+ larger in the US) holds. For example: https://www.zigguratrealestate.ph/post/how-big-is-a-house-av...

From my anecdotal experience, residential HVAC is fairly uncommon in EU. Lived in northern Spain and Netherlands for many years.

The H of HVAC stands for Heating. I presume almost all houses in Europe have heating?

A lot of heating in the UK is gas (so wouldn't drive electricity consumption) and a lot of homes in the UK do not have AC (recent news reports suggest it is under 5% of the homes have it)

Yes but is the heating in HVAC through temperature controlled air flow like for cooling?

Over here it is mostly using radiators with water heated with natural gas (same gas that was used for cooking when fire stoves were common).

> Yes but is the heating in HVAC through temperature controlled air flow like for cooling?

In the US and Canada it is very common to have a furnace that delivers heated air in residential houses.

Yeah, that does not surprise me. The apartment I stayed at in York was absolutely tiny. It was decent, and big enough for one person, and it was pretty cheap, so I'm not complaining really, but I've never seen an apartment that small in the US.

Also there was just no HVAC there to begin with, so I guess even less of an HVAC bill.

That’s ironic, because a lot of the apartments in New York are also very small.

It's kind of mad that the US houses are an average of 2000 square feet, yet if you watch some of the "New York apartment tour" videos on YouTube they are often far smaller than even what you'd find in London. The kitchens are often absolutely pitiful little spaces, especially considering the multi-thousand-dollar rents.

If you’re in downtown or midtown they’re small. I lived in Washington Heights (north Manhattan) for a few years and my apartment was two bedrooms with a relatively big living area, and I was able to afford that with an academic’s salary. I don’t remember the exact square footage but my wife and I lived there and it didn’t feel cramped at all. I own a house in Brooklyn now and if you count the basement it’s about 1600sqft.

Though York is a fairly rural town, and houses/apartments that small in rural America, as far as I am aware, are basically unheard of.

There's lots of places in the US that don't have natural gas infrastructure and do all heating electrically. The UK has a much higher population density so services like natural gas are more widely available, I'd guess with no evidence to back that up.

In the UK, places without natural gas almost all use oil for heating instead.

A small chunk of buildings built in the 60's use electricity because we thought that would be cheap in a post-nuclear world. We were wrong.

In the US there are lots of places where electricity is fact quite cheap like that. For example, in my county heating with propane doesn't even come close to making sense, due to the excess of cheap hydro power.

Quite a few people use LPG where nat gas isn’t available. Converting nat gas equipment to LPG is quick and simple.

Simplest explaination - air conditioning - which isn't much used in the UK.

Keep in mind that the UK is much smaller and has a colder climate in general. If you look at a state like Colorado, the energy usage is vastly different than Florida or Texas with lots of heat and humidity.

I would bet that the southern states skew the results quite a bit for the entire USA.

Here in Australia the coldest state (tas) uses more energy (8600) than anywhere else (e.g. qld 5500). They have basically 100% hydro power and use reverse cycle AC for heating. Not sure what else is going on there.

>If you look at a state like Colorado, the energy usage is vastly different than Florida or Texas with lots of heat and humidity.

Electricity usage yes. Energy usage no. Household energy usage is lower in the warmer states, and higher in colder states. I would expect that CO household energy consumption would be higher than FL or TX.

Yes whoops. I should have made that distinction. The parent comment was talking about electricity, and that’s what I meant.

I would argue that the USA as a whole generally has more climate variability than the UK in addition to larger housing to account for the overall energy usage as well.

> Household energy usage is lower in the warmer states, and higher in the colder states.

that's quite the assertion, what makes you believe it to be true?

> Apparently the average American residential electricity use is 10,791 kwh/year, which is ~1,231 watts, whereas the average British home is only 2,700 kwh/year which is ~308 watts. I had no idea that the difference was so large.

Well, American homes aren't built out of brick and concrete like European buildings are, instead they're made out of wood and cardboard which is barely insulating against heat (and doesn't hold up at all to major storms which is why you're seeing so much destruction after hurricanes), so they lose a lot of energy during winter and have to spend a lot of electricity on AC during the summer.

On top of that, their homes are (at least in suburbia) so much larger than European homes. Heat loss/influx is cubic-related to the footprint IIRC, so it makes for much more energy demand as well.

They main reason is that US has a higher percentage of all-electric homes. The average medium sized UK home uses 2700 kWh/year of electricity and 11500 kWh/year of gas. See that table in your second link.

What you want to compare is average household energy use excluding transportation. For the UK the numbers in your link give 9400 kWh/year for 1-2 people in a flat or 1-bedroom house, 14200 kWh/year for 2-3 people in a 3-bedroom house, and 21100 kWh/year for 4-5 people in a 5-bedroom house.

I'll leave it to someone else to find out how those are distributed to work out the average for the UK as a whole.

For the US, in 2011 [1], annual usage was 108 MBTU for single family detached houses, 89 MBTU for single family attached houses, and 54 MBTU for multi-family housing. In kWh that's 31700 kWh, 26100 kWh, and 15800 kWh.

I'll leave it for someone else to find the distribution so those can be combined, and to find later data. Almost all searches for household energy US of US households just return electricity usage and the 2011 document was the only thing I found that gave what I was looking for.

[1] https://www.epa.gov/sites/default/files/2014-03/documents/lo...

probably due to a combination of pricing, house size, and lack of air conditioning in the uk as mentioned.

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