There's was 2 or 3 where i had no idea, guessed and was a way off.
There's was 1 where i did a hail Mary and got it. It was interesting how some even towards the end were really obvious and others were really subtle - I'd say I did better with purple tones and worst with the blue / greys.
> Heat pumps don’t work well on old, poorly insulated houses in cold climates. If they can keep up, which is a big if, the price of electricity generally dwarfs natural gas, even if the heat pump is running at 250-300% efficiency.
I've got a 1930s semi-detached house (UK, north of England) - heated solely by a ASHP for both heating and hot water.
Our Seasonal Coefficient of Performance is currently 3.47 (347% efficient) - even if limit that to just last month (coldest month of the winter so far in the UK) our COP was 3.25 (325% efficiency).
Roughly speaking if you can achieve a COP over 3.2x in the UK it should be roughly on a par with gas, assuming you go 'gas free' (i.e. you can make the saving on the gas standing charge).
Personally we're running at ~£200 annual saving vs. my estimate of what costs would be for equivalent gas boiler - that's thanks in part to being able to do all our hot-water heating at night rates.
House wise - we don't have cavity wall insulation, have 15+ year old double-glazing and probably should have more insulation in the loft (it fills the rafters but I think these days that's considered not enough).
Also with changes to ECO (energy company obligations) and RO (renewables obligations) the differential between gas and electric will reduce further
Anyhoo - added my example to show that ASHP can work perfectly fine in old, poorly insulated homes in (moderately) cold climates.
The issue with poorly insulated houses in cold climates is not about efficiency. The issue is that the thaw cycle makes it impossible to actually come up to temp because too much heat is lost during thawing. Most of the UK isn’t really considered “cold”, which is probably why you don’t have this issue.
Yeah the UK isn't really very 'cold', but figured would include my example to show that not a problem in UK-equivalent of cold climates.
From a quick skim around it appears ASHPs can continue to work at -20c even -30c IF they are units that were designed for cold climate operation, albeit they can't secure the same SCOP/efficiency as they can with warmer temps.
It also looks like homes in these colder areas will often install the ASHP + have some form of additional heating as a back-up (e.g. electric heating) to compensate for the limitations of the ASHP in the coldest weather.
> Some chargers are configured to start charging exactly when a cheaper tariff kicks in, which causes big transient issues for the grid. I think modern chargers have a random delay to help with that.
Here in the UK some electricity providers offer 'smart' charging (e.g. Octopus Intelligent Go).
In that situation the energy provider controls when to charge the car - e.g. you say "I want the car at 80% by 7am tomorrow" and the energy provider controls the timing of charges.
That's how my EV charges - I plug it in, and Octopus control it.
Benefit for me is that whenever the car is charging my entire home's use gets the overnight rate (even if part of the schedule is charged during the day).
Benefit for Octopus is they can use my car to balance grid demand / schedule the charge when it is most financially effective for them.
I can - at any time - override that logic if I just want it to charge at a specific time for whatever reason.
(I presume this sort of arrangement is becoming more common in other countries too)
> I'm a little confused by this, aren't AirTag basically circular discs pretty much just big enough to house a CRT2032 battery?
Kind of. It's definitely the intention, but an AirTag is still considerably larger than the CR2032 within it [1], so they're not at a shortage of space in the shell.
As for "teardrop shape", I didn't mean to imply it had an elongated shape, but that it's rounded off on all sides, like a drop of liquid. The absence of any defined edges makes clip design harder and forces any AirTag enclosure to just act as a mini-pocket that contains the whole thing instead of having a simpler and less wasteful attachment method.
Take the following link which is part of an Defra (UK gov) funded initiative called 'Trees Outside of Woodlands' and constitutes a public map showing lone trees, groups of trees and small woodlands across England.
There's was 2 or 3 where i had no idea, guessed and was a way off.
There's was 1 where i did a hail Mary and got it. It was interesting how some even towards the end were really obvious and others were really subtle - I'd say I did better with purple tones and worst with the blue / greys.