glxxyz · HackerTrans

glxxyz

há 7 mesesdiscuss

Remember during Covid where every restaurant's menu was a QR code on the table that linked to a PDF in S3?

glxxyz

há 8 mesesdiscuss

[^X] means any character other than X, so [^X]* matches zero or more of any characters, so long as none of them are X.

glxxyz

há 8 mesesdiscuss

Check the diskette for physical damage on the recording surface and at the hub centerhole.

glxxyz

há 8 mesesdiscuss

> I’m guessing you’re not counting the fact that if you buy a stock for $100 you still have the $100 (you can sell the stock)

Your guess is wrong. A better term for what I calculated is the IRR of a series of cash flows. You're correct that stock is a liquid asset, I'm obviously aware that I can't liquidate the panels attached to my roof.

This whole thread got out of hand, I was just giving the anecdote that I saw a much better return on a heatpump than a solar installation. I don't care who believes or doesn't believe my calculations.

> Easy to verify though: what was your install cost and how much is it saving you on energy bills?

A rough estimate is given on my original comment in this thread.

glxxyz

há 9 mesesdiscuss

Yes the calculations are different for natural gas, I don't have that option. Rural properties here (south/central Ontario) typically use delivered oil or propane supplemented by firewood.

I recently thought about running a BBQ gas line from my main 500 gallon propane tank, but with delivered propane close to $1/litre right now and a 20lb tank holding about 18 litres there's no saving over just using with the portable tanks. I prefer being able to move the barbecue around too, although I probably would run a line if I had an outdoor kitchen type setup.

glxxyz

há 9 mesesdiscuss

That makes more sense, but your utility's failings are not necessarily the same as mine nor anyone else's.

I wish I'd never mentioned solar nor net metering now- I'm not on some crusade to promote either, I was just explaining the economics of my personal setup.

glxxyz

há 9 mesesdiscuss

> I can’t imagine the math is any better in Canada.

I don't have to imagine, I've actually installed it and I can see the impact on my bills. By most estimates it has a 12-15 year ROI that matches the stock market, and will continue to generate electricity for another 10-15 years after that. The 'math' is a function of many things: orientation, roof angle, occlusion, installation costs, electricity cost, latitude, grants/loans, net metering terms, etc. It's a huge assumption to say that what doesn't work in one location in Cleveland won't work for a property in Canada 2 degrees further north.

glxxyz

há 9 mesesdiscuss

The point of my original post was that I’ve seen a much greater ROI on my own heatpump than solar, even though I don’t regret the solar installation. I wasn’t making any claims about sustainability/scalability of solar, just showing how it worked for me.

glxxyz

há 9 mesesdiscuss

It is for a fraction of consumers- power companies and governments are well aware of that.

glxxyz

há 9 mesesdiscuss

I’m not sure what you mean by ‘unsustainable’ nor ‘critical mass’ here. Of course not everyone can net meter- on a sunny but mild day with no-one using A/C nor heating and everyone contributing back to the grid it doesn’t work.

My local utility is well aware of that, applications for permits to net meter have to be made, and only a fraction (something like 15%) of properties in each area can net meter. Also the government is aware and there are no grants for net metering, only for battery systems.

I’m giving details about my personal system for one property in one location, not in any way making a statement about what works for anyone else.

glxxyz

há 9 mesesdiscuss

The issue for me with batteries is that in the summer I can produce in a day much more than I can use, and in winter I consume a lot and barely produce anything. This is where net metering steps in- I can ‘store’ all of my excess summer consumption in the grid in summer and get credit for it in winter.

A cheaper smaller system right sized for summer consumption with a battery would have my second best option, but for me never showed any potential payback due to the fixed costs of installation and the extra battery costs.

glxxyz

há 9 mesesdiscuss

I think the argument is that on average people are buying heat pumps and EVs faster they are installing solar panels but it’s not completely convincing though, power stations can be added.

Further north where I am solar can only ever be a small component of total electricity generation due to the dark snowy cloudy winter months with close to zero solar generation for weeks on end.

glxxyz

há 9 mesesdiscuss

Yes the people selling solar systems all factor in aggressive future electricity increases, it's best to also see how it looks with more conservative rate increases. By my calculation in a reply above with the interest free solar loan it's an 8% return over 14.3 years.

glxxyz

há 9 mesesdiscuss

Yes the figures are my approximate bills so include net metering revenues.

You're right about the 8 year negative IRR for the heatpump, although I'm being very conservative about propane costs, it's likely much shorter. I was pretty conservative about the solar savings too, I generally go for the worst case in these estimates.

Your overall NPV calculation seems a bit off. It's ~21 years to zero NPV at 8% discount rate, spending $80 up front to save $8/year. Factoring in the 10 year interest free government solar loan makes it more like 14 years. My working:

    =nper(8%, -8, 80)
    20.9

    =nper(8%, -8, pv(8%, 10, -4)+40)
    14.3

The solar system is fun to tinker with and should pay off 'eventually', it's not a no brainer of a decision like the heatpump though.

glxxyz

há 9 mesesdiscuss

There was a C$7k government grant at the time for the heatpump, which roughly matched the tax.

The current Ontario solar grant is weird- it only applies to battery systems without net-metering. They also offered a 10-year interest free loan though so I took that, improves the ROI a little. I think battery systems do make more sense for people who are further sound and using more electricity at the time of year that they are generating it. The solar sales people estimated a 10-year ROI but they had to include a pretty high annual energy cost increase in their calculations (I think 8%/year), I estimated more like 15 years.

I didn't really consider replacement, by all reports the WaterFurnace pump should last 25-30 years and the propane furnace was probably 5 years old so would have lasted about the same. I would think that the WaterFurnace costs a little more to replace, maybe a winter's worth of propane.

Several people told me that ground source heat pumps were too expensive, but years later it still feels like the best investment I've ever made, the gentle heating and cooling is more comfortable too. Anyone with enough space who has to have fuel delivered (propane, oil, etc.) should seriously consider it.

glxxyz

há 9 mesesdiscuss

People told me that, but I did the calculations myself and the impact on my energy bills is real. Net metering is essential though, so not everyone can do it.

Compared to say SoCal I generate 2/3 as much per year, much less evenly- a lot more in summer than winter, whereas further south there's less variation year round. Cooler temperatures improve solar panel efficiency too. There are online solar potential calculators if you want to compare for yourself.

glxxyz

há 9 mesesdiscuss

Yes horizontal loop, 200 metre trench ~2m deep with 6 pipes at the bottom. Took 3 days for a 20 ton excavator to dig and fill in the trench. Maybe I got lucky with the installer but it wasn't eyewatering. Vertical loops do cost a lot more. Repairing the lawn with turf or professional landscaping would have cost more than the install, so I did it myself with a tractor, some spare topsoil, and a few bags of Costco grass seed.

glxxyz

há 9 mesesdiscuss

I'm in Canada at a similar latitude with ground source, resistance heating normally kicks in at about -25C (-13F) or so, just a few hours on the coldest nights, doesn't cost much. I could probably leave the breaker off too, I wouldn't mind it a degree or two colder.

glxxyz

há 9 mesesdiscuss

The prices when I looked weren't that different- it was about C$30k Canadian for air source and C$40k for ground source (which I went with).

glxxyz

há 9 mesesdiscuss

I'm amazed at these prices, I replaced a propane tank + furnace with horizontal loop ground source for $40k Canadian (+ tax, but government rebate matched that). It's almost paid for itself in about 6 years, I gave more detailed numbers in another reply.

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