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Comment by zowie_howie | Hacker News Reader

Is it immediate? Sure, there is satisfaction that you are using 'free' electricity. But it does have an upfront cost. I calculated that it would take over 11 years to recoup the investment based on our current usage. Given we already get cheap night-time rates to charge the car and run appliances, it is hard to justify.

Like many UK houses, we have gas central heating too. I guess if we had a battery too (more investment) then we could switch to using electric oil-filled radiators, though they would not heat the whole house. And we could install a hot water tank.

I guess for new builds there is a real opportunity, but for an existing household I'm struggling to see how it works - and I want it to!

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I don't think it ever makes sense to switch to electric radiators. It might make sense to switch to a heatpump, but you need to avoid being hugely overcharged by the installers and there are flow issues if you have 8mm piping.

This ROI calculator looks reasonable: https://ukcalculator.com/solar-panel-roi-calculator.html - note that it subtracts the install cost for you, so any case where the final figure is positive is profitable. But of course that depends on whether grid prices go up or down in the next decade ...

Well France did move to electric everything (cooking, hot water, heating) in the past thanks to ample nuclear electricity production (and possibly not too harsh winters). Unfortunately they let their nuclear programme decay and are struggling now (EU grid integration does not help)...

I think a big part of the push to install heat pumps now is that it is understood that electricity production is in dire straights, taking into account that the transition to EV requires a lot of electricity.

Part of the struggle is that renewables have state aid exceptions, enabling massive taxpayer funded subsidisation of the """industry"""

> hot water, heating

Not really. Urban flats frequently got resistive heating (rather than heat pumps) but when France finally phased out furnace oil it phased in gas heating (again instead of heat pumps).

And EU grid integration was mostly a boon, at least to EDF, with the country able to export its large stable supply and arbitrage between its neighbours.

It largely missed its opportunity and should have ramped up electric use way more aggressively in the 90s. And built up research labs and industrial and practical knowledge in heat pumps and batteries tech.

What "not really"? Electric hot water and electric heating is very common. Almost 40% of homes have electric heating and that's the top heating type [1]...

[1] https://franfinance.com/les-francais-et-le-chauffage-de-leur...

> Almost 40% of homes have electric heating and that's the top heating type

It's 40% of households not homes, and per your link it's 55% of rentals.

That's the urban flats I mentioned, they use inefficient resistive heating because that's cheap to install (no plumbing and no vents, just the electrician adding a circuit per radiator from the box).

So, leaving aside your nitpicking about households vs homes (which are synonymous here), you agree with me then? What was the point of your comments?

> So, leaving aside your nitpicking about households vs homes (which are synonymous here)

The mistranslation gives the incorrect impression that owners have migrated their personal residences to resistive heating and that this is the normal heating method for the country.

Landlords cheaping out on heating is a completely different situation, and does not support your assertion. Especially with (again per your link) renters are significantly less satisfied with their heating situation than owners.

> you agree with me then

No.

I think you are either being argumentative for the sake of it, or you are confused about the meaning of "homes", or both.

I think both.

UK also has massive subsidies. I know someone who got a government subsidy, the company didn't complete the job, got paid for the government for the full job, and they calculated the payback was 50+ years.

At this point, I do not understand how anyone can possibly believe that the people advocating for this stuff are thinking in terms of economic (as opposed to political or social) returns. This stuff makes no economic sense and is already bankrupting the country.

Also, there is a legal requirement for new builds to have this now, this is with a massive shortage of housing, with a government that is a government of the "people" but has just put out the same housing targets as the last one and is running 75% behind annually. The scale of subsidies being given to these industries is probably tens of billions, green energy subsidies are now 5x larger than industry profits...this makes no sense, even with sky-high electricity prices (to be clear, it is consumers who are ultimately paying for this...we pay higher prices so that a lawyer somewhere can prattle on about leading a "green revolution" that is lining the pockets of donors).

I can't speak for the UK, but ... I did my own install of a 6.7kW ground-mount array. The materials cost me about US$12k. That meant just 7-10 years until payback. Sure, I saved on labo(u)r costs, often the most expensive part of the work, but the overall point remains ... it absolutely makes sense, at least in the "right" parts of the planet.

It isn't just the "right" parts. Yes, the UK has less sun but ground mount is not happening in the UK because average dwelling size is so mall. So typically installed on roof of much smaller properties which costs significantly more for far less solar panel. Detached homes are also rarer than the US because of the issues with supply of almost all goods/services in the UK so there are more issues with tree cover. And, of course, almost all the marginal demand for solar panel is through government subsidies which adds even more cost.

Guy I spoke about above lives in a part of the UK with less sunlight, there was extensive tree cover around his property, and the job was done incorrectly (but full subsidy paid). As I said, there is wilful corruption and, therefore, it is impossible to engage with this subject on the basis of rational economic thought. Companies receiving the subsidies pretend to be doing work and politicians pretend the companies are saving the environment.

I confess to still not understanding why roof installs cost so much more.

My ground mount array(s) required concrete foundations that were 5' deep and 17" in diameter, and the frame cost $2k in iron piping. There's nothing remotely comparable in a roof install.

I guess people just charge more because "we're on your roof, which is tricky".

Are you talking about rooftop solar?

For an 800W balcony system your background house usage is likely to be enough to self consume most of it.

You'd wouldn't be able to run even a small oil heater except maybe in peak summer.

It's a good match for working from home as it's a small amount of power spread over daylight hours.

There are a variety of small simple oil heaters in the UK under 800W. You're not going to heat a house with something like that, and obviously you'd be more likely to need one when it isn't sunny, but it seems the 800W balcony solar could run such an oil heater.

Yes it's probably more practical that it's powering your laptop and the coffee maker and that sort of thing.

Ideally, the problem will solve itself. People will get angry with increased energy prices, and elect politicians who promise to bring them down (The most effective and visible way being home solar subsidies, while reducing gas/coal).

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