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Harnessing America's heat pump moment

heatpumped.org

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Re: Harnessing America's heat pump moment

#521

Post by kragen »

Marsymars wrote: post #469
kragen wrote: post #128

> what it’s going to take, from the human side of the equation, to make heat pumps the obvious, accessible, and default choice for millions of American homes. Well, this has already happened; living in a third-world American country, I've been heating my houses in winter with heat pumps every winter for many years (even though they iced up occasionally) and most air conditioners here are already heat pumps. Frio/calo…

> But, installations strictly for heating are probably never going to happen en masse. In https://news.ycombinator.com/item?id=45698730 I analyze the costs. It turns out that heat pumps cost around 39¢ per peak watt they save, while low-cost solar panels cost 6.5¢ per peak watt they produce, so it's almost always cheaper to install enough solar panels to heat your house resistively. And that gap is going to continue…

Either that or solar panels, yeah. I mean it sounds like US utilities are doing a pretty bad job of delivering the unprecedentedly cheap solar power of the last three years to their customers in any case. They're still acting like we're in an energy crisis! So you have to install the modules yourself.

Re: Harnessing America's heat pump moment

#522

Post by orev »

gardenhedge wrote: post #352
orev wrote: post #142

Earlier quoted context omitted.

Heat pumps are just air conditioners in reverse. They use the same amount of electricity whether heating or cooling. While many people have air conditioners, and grids seem to be able to handle them in the summer, an assertion that the grid can’t handle them in the winter is doubtful. Plus there are fewer people using them in the winter (just because fewer are installed). Most people in the NE heat with oil, gas, or…

I have a heat pump, along with hvac. It only produces heat. Is it possible to get it to produce cooling too or is that an entirely different system?

I’m not an expert, and it would depend on the system you have anyway, but AFAIK the main differentiator between a cooling air conditioner and a heat pump is a “reversing valve”. You may simply need to change the mode to reverse it, then you get cooling. From what I understand, it would be unusual for it only to work in heat mode.

Re: Harnessing America's heat pump moment

#523

Post by Reason077 »

glxxyz wrote: post #511
Reason077 wrote: post #510

Earlier quoted context omitted.

Exactly. Not a sustainable/scalable policy.

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.

My comment was regarding net metering policy, not solar itself. Solar is great, and even better (for you) if you have net metering. But it’s not sustainable or scalable for utilities to keep offering net metering, and ultimately it creates wrong/distorted market signals: an incentive to generate more electricity when it’s abundant and to use more when it’s scarce.

Re: Harnessing America's heat pump moment

#524

Post by SoftTalker »

Marsymars wrote: post #413
SoftTalker wrote: post #404

Earlier quoted context omitted.

In the US, most people don't live in one house that long.

That should be a wash with the value that a house gets sold for.

Yes and no. A house's value is largely based on the price of other comparable houses in the area that have recently sold. It's very possible to "overimprove" a house and you will not recoup those costs when you sell. Whether the furnace is brand new or 10 years old will have a negligible impact on the selling price.

Re: Harnessing America's heat pump moment

#525

Post by caminante »

PaulDavisThe1st wrote: post #478
caminante wrote: post #398

Earlier quoted context omitted.

> There is (according to my sensors) a fairly large CO2 increase inside a room when a modern furnace If this is happening, then you shouldn't be using that furnace/room! Something beyond the furnace is not configured right.

Could also just be the furnace. Incomplete combustion conditions can give rise to the symptoms mentioned here.

I doubt it's the furnace, unless there's a serial defect/recall.

The problem is likely "between the keyboard and the chair." ;-)

Re: Harnessing America's heat pump moment

#526

Post by tgma »

occz wrote: post #502
tgma wrote: post #289

Earlier quoted context omitted.

Electricity is much more expensive than gas per J. You have to be ~3x more efficient to just break even.

As it turns out, you regularly get a COP of >3 from heat pumps, as they don't need to generate the heat, they steal it from somewhere else (outside)

Right and you simply break even there so there's not much upside in terms of variable costs unless your electricity is somehow cheaper and not mainstream California prices.

Re: Harnessing America's heat pump moment

#527

Post by Animats »

jofla_net wrote: post #241
Animats wrote: post #192

Everybody seems to agree that installation costs way too much. There's a few parts to this. Everything has to be carefully sized - power, pipe sizes, unit locations. You need to put a house's thermal profile (how much heat loss, how much air leak, how much thermal mass) along with the regional thermal profile into an engineering calculation which computes what you need. Thermographic inspections are a thing.[1] Usual…

or you could, you know, wing-it, like they do overseas, and I tell you, the world does not end.

That's fine for mini-split pairs. Whole house systems need more engineering.

Re: Harnessing America's heat pump moment

#528

Post by Marsymars »

kragen wrote: post #521
Marsymars wrote: post #469

Earlier quoted context omitted.

> But, installations strictly for heating are probably never going to happen en masse. In https://news.ycombinator.com/item?id=45698730 I analyze the costs. It turns out that heat pumps cost around 39¢ per peak watt they save, while low-cost solar panels cost 6.5¢ per peak watt they produce, so it's almost always cheaper to install enough solar panels to heat your house resistively. And that gap is going to continue…

Either that or solar panels, yeah. I mean it sounds like US utilities are doing a pretty bad job of delivering the unprecedentedly cheap solar power of the last three years to their customers in any case. They're still acting like we're in an energy crisis! So you have to install the modules yourself.

A normal solar panel install wouldn't let me move to resistive heating regardless of size, my house simply isn't serviced with enough amperage. My gas furnace is 100k BTU give-or-take, so I'd need >100 amps for heating alone.

Re: Harnessing America's heat pump moment

#529

Post by sholladay »

scottgg wrote: post #424
sholladay wrote: post #356

We had a heat pump installed last year. It’s advertised as a cold-climate heat pump and it’s “good enough” for us, but it’ll never again be toasty on a cold night, just relatively warm. When under heavy load, it also has some kind of loud vibration issue, I think in the lines that run from inside out to the condenser. The system is an Ecoer, which is a Chinese company that pretends to be a U.S. company. And it has a…

Sounds like it wasn’t sized well?

It’s the largest residential model that Ecoer makes. The home is a 3-bedroom, large but nothing crazy. The installers said they erred on the side of too big, rather than too small, and that’s corroborated by my back-of-the-napkin math and Google searches indicating that “too big” is standard practice in the HVAC industry. So in theory, it shouldn’t be a lack of power. I think it’s poorly optimized. From what I’ve been reading, the pressure in the lines is very important. I have no idea if they are pressurized properly. The unit apparently has sophisticated monitoring of the line pressure, but the IoT gateway has no end-user access which is a huge red flag for me that I wasn’t aware of before it was installed.

Re: Harnessing America's heat pump moment

#530

Post by radu_floricica »

It's... a bad article?

It takes as given that the tech is here, and it's economically feasible, but it's not giving any arguments. Just blames the people.

It's also not exactly defining the problem space. Is it talking about air-air AC with heating? Those are common and very cheap. Is it talking about large HVAC systems that include hot water? Those are indeed a hellof a lot more expensive, but also a hellof a lot more complex. And no matter what the author is saying, technology isn't to the point of giving us hot water from heat pumps. The math just isn't mathing - to take cold water and heat it up to "hot" by cooling off freezing air, you'd simply have to cool huge amounts of air. Yeah, probably, if you put a room-sized HVAC system and spend a ton on electricity - but that's where it stops being competitive.

Is it talking about geothermal heat exchangers? Because those are indeed a lot more efficient - but also more expensive for obvious reasons. You need to drill.

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