this post was submitted on 30 Apr 2024
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Climate - truthful information about climate, related activism and politics.

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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world.  About 1C of total warming.  Second chart:  about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability.  Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases.  About 0.5C of cooling with large error bars from SO2.

Recommended actions to cut greenhouse gas emissions in the near future:

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[–] [email protected] 3 points 6 months ago (2 children)

Hmm, I couldn’t find anything about tankless heaters. I absolutely love that I never run out of hot water, especially after my wife takes her shower.

[–] [email protected] 10 points 6 months ago (2 children)

Per the actual rule:

As discussed in section II.B.3, DOE is finalizing standards for all consumer water heaters, with the exception of gas-fired instantaneous water heaters, in this Final Rule.

So there has been no change to the rules for tankless heaters.

[–] [email protected] 4 points 6 months ago (2 children)

Believe It or not there are electrical tankless heaters. I actually installed one not too long ago because it made sense in a very odd application.

Mostly they're a terrible idea though.

[–] [email protected] 4 points 6 months ago

Yeah, they're pretty rare and almost never the best option. I don't think I've actually encountered one.

[–] [email protected] 1 points 6 months ago (2 children)

We’ve considered switching to an electric tankless WH. What makes them a poor choice?

[–] [email protected] 4 points 6 months ago (1 children)

Extreme energy use for pretty low deltas on temperature. Best possible efficiency is 100%, far less than the 2.5+ cop a heat pump unit will get you. If it's at all manageable, get the heat pump.

Frankly, their inefficiency means the emissions they cause are still pretty bad unless you know your energy source is more renewable than most.

But they don't need venting, which is nice. They do take a big fat electrical connection though - the one I installed was two 2 pole 40a breakers - hopefully you have at least 200A service. Mostly they work as intended.

[–] [email protected] 1 points 6 months ago

Thanks. That makes sense. We installed a gas tankless after looking into electric tankless. The lack of venting looked really attractive until I blanched at the wiring we'd need to pull. My experience with tanked electrics was that they take a long time to recover. Is this also true of heat-pump based tanked WHs?

[–] [email protected] 1 points 6 months ago

Most of them are actually coal fired.

[–] [email protected] 2 points 6 months ago (1 children)

Is that because they were already efficient or because they can't reasonably be made more sense efficient?

[–] [email protected] 3 points 6 months ago

I would assume both. They transfer basically all the heat generated into the water and only heat when water is being used.

[–] [email protected] 2 points 6 months ago (1 children)

We switched to an externally mounted tankless when our big ole water heater conked out. It's way more energy efficient, but everyone has to run the water for a good minute until it kicks in and makes it through the pipes

I'll look into a heat pump once this one dies, but running water during a drought is just wrong.

[–] [email protected] 1 points 6 months ago (1 children)

This Old House has episodes where they have a small recirculation pump to keep lines primed with warm water.

[–] [email protected] 1 points 6 months ago

This kills the efficiency gain of not keeping a hot tank though.