261–270 of 406 posts
The article mentions the most important point towards the end: “The better you insulate, the less heat you need in the first place,” No heat pump will help if your house is leaky or under insulated.
You’re describing my situation. How do you de-leakify a house?
Earlier quoted context omitted.
> Then, what's the point? If you still have to have gas lines and infra, just use the gas. It's vastly cheaper. A) Not everywhere B) Heat pumps can be powered with solar, reducing costs even if your gas would normally be cheaper C) Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons
> Some people are willing to spend a little more if it helps push electrification forward, for environmental reasons It's not a little more though, that was the point. In my area, California, it's about 4x more. Gas here is so cheap, it's almost free. Anecdotally, I don't know anyone who's opted into the "green energy" plans offered by the area's utility providers - because they all cost a lot more than regular. Peop…
There will be a feedback loop once that really starts: individual prices go up because infrastructure costs remain the same, but less people are using gas. Once natural gas prices go up, people will switch to more efficient appliances, or switch to electricity. Forcing prices to go up some more to make up for infrastructure costs.
I agree with you about people following their wallets and that's why people will want to change to heat pumps when gas becomes too expensive. Remember the prices in December?
Earlier quoted context omitted.
60% would be terrible thermodynamic efficiency for a cogeneration plant. Modern CCGT systems crack 60% thermodynamic efficiency for just the electricity generation. With cogeneration, system efficiencies are typically in the 70-80% range.
60% is feasible for e.g. nuclear and gas, if you use more than one turbine and there is a big constant temperature differential. This typically isn't the case for gas plants which are intentionally variable and often intended to be cheap to build. While at peak temperature, they might run at peak efficiency around the theoretical maximum of 60% (thermal to electric) with a multi-turbine assembly, typically efficiency…
The brand new EPR achieves only 37% thermal efficiency and that is considered a good number for a power reactor:
https://www.world-nuclear.org/information-library/nuclear-fu...
The article mentions the most important point towards the end: “The better you insulate, the less heat you need in the first place,” No heat pump will help if your house is leaky or under insulated.
You’re describing my situation. How do you de-leakify a house?
Do a blower door test and see where the air is coming in/out:
* https://www.energy.gov/energysaver/blower-door-tests
* https://www.youtube.com/watch?v=msZ_E-4GFs8
* https://www.youtube.com/watch?v=Q5vHxgq7GKo
Then plug the holes.
Earlier quoted context omitted.
That must have included furnace replacement components for cold weather (e.g electric heat strips). Otherwise, heat pumps are essentially the same as modern A/C units.
Almost certainly. Proper/modern heat pumps do not need heat strips until -20F or so
Earlier quoted context omitted.
Not only that, but since a heat pump is at least 3x as energy efficient as the most efficient gas furnace, using one results in about 1/2 the E2E CO2 emissions as the gas furnace when the grid electricity being consumed is natural gas based. If you live in an area with abundant zero emissions electricity, then you are heating without any C02 emissions at all. That said, we should do both heat pumps and insulate bette…
Your numbers are off. Thermal power plants typically do have a thermal-to-electric efficiency of around 30% (40% max), so with your heatpump having an electric-to-thermal efficiency of an assumed 300%, you end up with basically no difference in CO₂ emissions. Note that there are some misleading efficiency claims for gas plants around 60%, but those are not for thermal-to-electric efficiency but for generating electri…
Wow, I never cease to be amazed at how few of the HN comments have anything to do with the original post. I guess I'll jump on the bandwagon, while my comment is tangential, it does have to do with the article's focus on reducing greenhouse gases and fuel consumption. Switching to a heat pump should be done in all cases where a traditional A/C is being replaced, but the biggest bang for the buck is in how the house i…
In San Diego
Earlier quoted context omitted.
Can't you get backup heating in addition to a heat pump for the coldest days?
I live in FL and we have a backup resistive heating element that kicks in as needed. Mostly only comes on a few days in the year or for short bursts when there's a cold snap that the heat pump can't keep up with.
It's interesting how a sufficiently large local norm can affect perspective. I thought everyone had heat pumps for the longest time. I've rarely seen a building without them. I also live in the southeast where they're at their best. Then this recent rise in popularity elsewhere dispelled that notion.
Earlier quoted context omitted.
I always went with this description too, though oddly a "heat pump water heater" only works one direction, yet "heat pump" is still in its name.
all heat pumps work in one direction. You can't move cold around with any mechanism. Only heat can be moved. The difference is residential "heat pumps" just have a set of reversing valves so you can move heat from outdoors to indoors.
So.. they work in two directions.