Ottolay

I am just saying what the typical install is in the South East US. The heat pumps installed may produce some heat at 5F but they can't keep the temperature to the set value, so there are resistive elements (Aux heat) to make up the shortfall.

It's pretty common for people with heat pumps to have Aux Heat kick in during cold spells, which cause power grid overload issues.

I realize you can insulate a house well enough and have a good enough heat pump to avoid backup heat, but 5F or 0F days are rare enough that the codes do not enforce this.

The issue with heat pumps is that most of the ones currently being installed in South East of the US don't work well below +20F let alone 0F or -20F. Most of them are being installed with an electrical resistive backup heat, which is incredibly inefficient.

The problem is when a cold spell like Christmas 2022, with temperatures down towards 0F. All the heat pump users switch to resistive backup heat and it overloads the electric grid and we get rolling blackouts.

In my opinion, heat pumps are amazingly efficient at moderate cold temps, but they really need propane or wood heat backup for the really cold temperatures instead of resistive heaters.

I use public/private with the private key handled by Yubikey PIV functionality.

Feels like there is a business case for people willing to pay to reduce trip times for trans continental flights.

The problem is that the greenhouse gas impact will be higher for a supersonic trip compared to a subsonic one. This is on top of the issue that we don't really have a good low carbon alternative for longer range air travel (batteries don't have anywhere near enough specific energy). The best option we have is synthetic jet fuel produced from green electricity. Producing jet fuel that way is many times more expensive than fossil fuel jet fuel.

You can take precautions to avoid the oxidation. This is already done reliably on airplanes and in overhead power distribution, where aluminum wire is the standard.

There are also a new aluminum alloys (aa-8000) with better mechanical properties. The biggest issue is that that the trades/DIYers need to learn new processes. Treating aluminum wiring like copper wiring is a disaster. Also need to overcome the stigma from the aluminum experiment 50 years ago.

It makes a ton of sense to switch to aluminum in housing though. For the same current capability the wire is significantly cheaper, lighter, and stronger.

Generally agree, although I think it is largely an illusion. Many people die in car accidents they did not cause.

Lithium Ion batteries degrade very little with low C mid range charge cycles. The time/temperature/SoC degredation is greater. Hence why you don't want to leave a battery sitting at 100%.

RoHS does not just restrict lead. It also restricts use of mercury, cadmium, and several toxic compounds.

This is so cool. Viable for LED lighting in an off-grid situation when there is little sunshine for solar panels.