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Harnessing America's heat pump moment

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Re: Harnessing America's heat pump moment

#451

Post by Marsymars »

ssuds wrote: post #76
blahedo wrote: post #33

People are reluctant to install them because they don't work as well as the good old boilers we'd be replacing. I'm not saying they can't, and I'm not saying that there are zero models out there that work. But in practice, a lot of us that have interacted with heat pumps have the specific experience that they get anemic as the temperature goes down and eventually become unable to do much of anything. I live in the mi…

I just wrote a big thread yesterday responding to someone with similar concerns to yours ( https://bsky.app/profile/shreyassudhakar.com/post/3m3w3nra2h... ). Copying it here if it's helpful to other folks. FWIW, the challenges you are facing seem to be grounded in bad design and application, which happens more than it should and really sucks. We need to move the bar much higher for the contractors installing heat pum…

> 2) AC doesn’t reduce humidity as well. Unfortunately, this is a classic problem with oversized heat pumps. The key to dehumidification is runtime. A well sized system will run for longer, which will pull the humidity out of the space. If the system is too big, it’ll cycle on and off & not dehumidify.

What if I want more humidity?

(The traditional way with a furnace would be with a bypass humidifier, where ultimately, the energy to vaporize the water comes from whatever the heat source of the furnace is.)

Re: Harnessing America's heat pump moment

#452

Post by giobox »

LgWoodenBadger wrote: post #387
upcoming-sesame wrote: post #310

Earlier quoted context omitted.

Do you mean 6 A/C units ? I. e. 6 outdoor and indoor units regardless, this is incredibly cheap

Mini-splits these days are available as multi-head (I think that’s the term) units, where a single outside unit can supply 2,4, or 6 units individually and independently. They’re remarkable, and I would go for a mini-split system over a central unit 100 times out of 100.

> where a single outside unit can supply 2,4, or 6 units individually and independently

In my current home, I have two "heads" attached to a single outside unit, but they cannot operate independently beyond setting different fan speeds or closing the vent really. If one of the mini-splits is set to heat and the other switches to cooling, they will booth start cooling, or vice versa, the head units just blindly blow air over what ever is being pumped through the line and the last unit to send a command to switch mode "wins".

Maybe there are clever heat pumps that truly allow fully independent control of the head unit when connected to multiple heads, but given the flow of refrigerant has to reverse direction completely when switching between heating and cooling, I don't see how they can operate fully independently when they are sharing the same refrigerant lines.

There is only one reversing valve inside the outside unit for all the head units connected to one outside unit in my experience, but would love to see examples of systems that do permit this if they exist.

> https://en.wikipedia.org/wiki/Reversing_valve

Re: Harnessing America's heat pump moment

#453

Post by zemvpferreira »

wongarsu wrote: post #386
upcoming-sesame wrote: post #335

Earlier quoted context omitted.

Parent mentioned $600 for the install. I live in Portugal as well, paid around $500 for ~one~ mini split A/C install

I would expect that installing six is maybe twice as expensive as installing one. All the overhead of scheduling the technician, traveling to the location, getting the tools out, etc stay the same. Installing six is vastly more efficient and that should be reflected in the price GP still got an amazing deal

Maybe I wasn't clear but when I commented, I meant to say you could buy and have installed 6 mini-splits for $3000 (machines included).

Re: Harnessing America's heat pump moment

#454

Post by TeMPOraL »

caminante wrote: post #367
vanviegen wrote: post #298

Earlier quoted context omitted.

This is not whataboutism though. It's comparing two alternatives on a relevant aspect.

LOL. Can you please share your definition of "whataboutism?" And explain how bringing up a single alternative (plus flaw) is addressing the critique and NOT changing the subject?

"Whataboutism", like "dog whistle", is a name for an imaginary discussion pattern that doesn't occur in real life, but is super easy to point out in most conversations, allowing one to cry foul and "win" the argument (or whole discussion) through violence instead of reason.

This is pretty much the same as accusing a colleague of insulting you through PR they asked you to review, because there's an added line that says:

  class HOLEInstance ...
i.e. obviously they're calling you "assHOLE".

- "But wait, it's no such thing; it's a Handle for OLE component instances - it's part of support for COM stuff in those legacy reports..."

- "AHA! See also here, dear readers:"

   class HOLEClientSite // TODO: : public HOEComponent?
"Surely, you see how bad my coworker is! They badmouth our customers too, and even call them public harlots! Don't believe their lousy defense that this was a typo, either!"

This is what pointing out "whataboutism" and "dog whistles" is. Artificial, cross-cutting pattern that match easily, but don't correspond to any real phenomena.

Weaponized pareidolia.

Re: Harnessing America's heat pump moment

#455

Post by Marsymars »

doctorhandshake wrote: post #365
JeremyPOsborne wrote: post #242

Earlier quoted context omitted.

If we’re trying to bring down cost the this is the issue with so many contractors coming out. The cost of sales is about 10-15% of the installation in the US. So thats $2-3k in California per heat pump Try to get an install for $600 like in Japan when you have to pay $2k to find the customer. Let’s have a lower cost sales process. Review 12 companies online, pick top 3, ask them to come out.

Yeah in case it wasn’t clear - I wasn’t asking a million vendors to price the job, I was asking them to do a manual J so they could price the job. It took 12 to get 4 to do the manual J. The other 8 came on-site and then refused to do the calcs even though I told them before coming out that it was a prerequisite for me to consider their quote. I got a variety of explanations for why they weren’t going to do it, most…

I've had a similarly frustrating experience trying to get contractors to redo my gutters.

They seem fine with the gutter part, but once I explain my rain collection system and my requirements around specific downspout sizing and simultaneous overflow, they just seem to have no interest in doing the bit of work required to make it all fit together.

Re: Harnessing America's heat pump moment

#456

Post by jabart »

orwin wrote: post #397
steveBK123 wrote: post #376

Earlier quoted context omitted.

In US the labor & markup is a huge component. I got HVAC drop-in replacement quotes ranging from $7k to $14k for what upon some quick research was about $3k in hardware.

Can you do the installation yourself? In my country i have to make a HVAC technician come to check the installation and sign a paper before i can start mine (200€ for a 15 minutes job, but it's less than the 2-4k it would cost to not do it myself) [edit] i say that because my hardware is 2.5k euros, so ~3k¯dollars, so we probably have the same high end stuff, and i guarantee you it's not hard to install, and it can b…

Newer units (not all) in the US come pre-charged up to a certain size of lineset. Manufacturers can sell you a whole unit with a charge. The rest is easy to source locally though I haven't tried to get nitrogen myself.

Of course you have exactly one chance with your install this way until you have to call someone.

Re: Harnessing America's heat pump moment

#457

Post by Marsymars »

matwood wrote: post #380

I love heat pumps. Had one in my house in the southern US and am about to put one in my house in the EU. I also recently bought a heat pump dryer, also great. Very gentle on clothes, doesn’t need a vent, or the high power plug - just a drain like a washer.

I'm planning on getting a heat pump dryer, but 3x the price (in Canada) means a long break-even.

Re: Harnessing America's heat pump moment

#458

Post by the_cat_kittles »

i bought a mitsubishi minisplit, as well as a lineset, and installation tools (vaccuum pump, valve core removal tool, flaring tool, micron guage, nitrogen, pressure regulator, manifold) and installed it myself after watching several hours of ac service tech youtube videos. it was a little stressful but i saved 8,000 usd and i honestly feel pride every time i turn it on. its worked absolutely flawlessly. i recommend this route if you have the time!

Re: Harnessing America's heat pump moment

#459

Post by the_cat_kittles »

ssuds wrote: post #145
gwbas1c wrote: post #141

My mini-split was installed sometime between fall 2017 or spring 2018 when my house was built. It failed when it was 6 years old, and the lineset had to be replaced because there was too much acid in the insulation and it corroded the copper. The problem was that the lineset was in my walls, so replacing it would require ugly lineset in a highly-visible place on my house. All the quotes to fix / replace it were absur…

Quality control by the contractor is soooo important. Formicary corrosion like you described can happen if a contractor doesn't pull a proper vacuum on the system to evacuate moisture before releasing refrigerant. I saw an anecdote where Bill Spohn, who literally owns an HVAC tools company, had this happen with the contractor installing a system in his own house! ( https://www.heatpumped.org/p/are-heat-pumps-a-commod…

pretty sure the white insulation on the lineset, when exposed to moisture and UV, can create an acid that eats the copper. thats probably what happened

Re: Harnessing America's heat pump moment

#460

Post by Marsymars »

bluGill wrote: post #330
ip26 wrote: post #284

Earlier quoted context omitted.

gets to -30f where I live (about once every 10 years) For this specific problem, I'm always inclined to just keep a 1800W space heater or two in the closet.

It takes a lot more watts than that to keep the house warm.

Maybe? Conservative (i.e. any number assumptions here are all biased against the space heaters) napkin math: My gas furnace uses something like to 300 kWh per day to keep the house 30 degrees (C) above the outdoor temp. If I only need the space heaters to supplement an extra 5 degrees, that's actually pretty close to 2000 continuous watts.
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