I would be interested to see the math on replacing a cheap unit every 10 years versus an expensive unit that lasts 30. A few years ago, we replaced our 30 year old Carrier system with a new heat pump system that was relatively inexpensive. But here's the thing, the old system was not nearly as efficient from the beginning and it was much less efficient 30 years later. I'm not sure how much room for improvement there is with the new heat pump systems in regards to efficiency, but if the advances are significant every 10 years or so, it may net out to a positive.

Individually that's one way to look at it that makes sense. On mass scale though, if in 10 years someone can make one that's 50% better, it still behooves the world for the the units of today to last 50 years because even by then you won't have manufactured enough for everyone to have heat pump, let alone the most current one. Another way to think about it is imagine if instead of your unit dying in 10 years when you got a more efficient one you sold it to someone who didn't have one yet.

In general though, it's more the idealogy that gets me. It would be so easy to do a little more work to make things repairable, to use common parts, and ultimately create units that could last decades instead of lasting until an electric board has a short from dust or a pump predictably dies just outside of warranty, taking out an otherwise perfectly functional unit. It's just not viewed as the most profitable way, atleast not with how most people buy things today.

I think it could be profitable though, if you get enough people that can do the math and realize that over a lifetime it's cheaper than I think you could make that work. Additionally, it's not just about the cost over time but what happens when failures inevitably happen. Try having a repair done on any appliance today under warranty. First you have to go through the company and you get whoever they send and then you need their parts, if they are still available, which often they aren't. If the documentation on how to repair/maintain is opensource then you could potentially get anyone to fix it and if the components are COTS were possible then you aren't screwed when your 5 year old heat pump has an electrical failure because you can just but a new board (raspberry pi lets say) flash the software and install it.

I'm simplifying but I think you get the idea.

> That is to say, as soon as something goes wrong with them, they are garbage.

Can you unpack what you mean by this? Standard A/C's can be repaired - fans can be replaced, as can compressor motors. Also, better and more efficient heat pumps can be more sensitive to maintenance (or lack thereof), because they often achieve that efficiency through finer control of mechanical components or lower resistance components.

IMO, a bigger factor in the longevity of traditional A/Cs is that they tend to have single-stage compressors that are over-sized for their loads most of the year, resulting in short-cycling and therefore shorter equipment life.

Just because something "can" be repaired doesn't mean it makes sense to. With most appliances if you are going to hire something to fix it outside of warranty it will cost hundreds of dollars at a minimum and you are often not guaranteed a repair will work. Even if it is in warranty, often a replacement part will be needed that is not available or is not economical to have a person install versus replacing the whole unit and the company will just scrap the whole thing and give you a replacement (after you've spent hours on phone calls, emails and talking to technicians).

The most egregious example of this I will highlight is electronics. Ask any manufacturer to provide a replacement board for an otherwise functional heat pump, air conditioner, etc. They likely won't have one. And even if they do, are you now going to hire someone to replace it? Do it yourself? If you aren't mechanically inclined its option one which can be hundreds of dollars and if its option two you will now be doing it likely with no or poor documentation spending how much of your time?

Heat pumps are no more sensitive to maintenance than air conditioners (besides the use of longer hoses for the refrigerant movement giving more opportunities to generate leaks). Or atleast their nature doesn't mean they inherently need to be (maybe that's the better way to put it). Compressors, fans, radiators, inverters, these are things that have been made for decades and if you walk into any commercial manufacturing space you'll find examples last for decades. That level of quality just isn't offered for homes.

You are absolutely correct that over-specifying heat pumps is also a big issue. That's kinda've a whole nother topic though that we could get into along with energy modeling, regualtions/practices, etc.

It's quite often cheaper to purchase a completely new unit than to fix an old unit.

Factory supplied parts disappear fairly rapidly after products are end-of-life and labor to repair can be quite expensive.

This is true.

We have a decent-quality Mitsubishi unit that's 7 years now. Last year, one of the main boards died. Living in a country with strong consumer protection, I was able to argue my way into having Mitsubishi cover the cost of a new board, I just had to cover labour.

If I'd had to cover all the cost, it would have been more than 40% of the cost of a new unit, and then you start asking yourself if it's worth it.

Even though the marginal cost of the main board is likely below $50, the replacement ones sell for close to $500.

I will add to this that in the USA Mitsuibishi is one of the highest quality ones you can get with the longest warranty (10 years last I looked).

Hey - I've been following the steady stream of articles and discussion here about heat pumps, so I have a question that is tough to answer from the articles.

Is heatpump popularity regional? My understanding was that heat pumps are the technology behind residential AC, heating, and commercial HVAC. Thermodynamic 4 step cycle of a working fluid with expansion, compression etc. Every house I've lived in has had one. The cycle is reversed to cycle between heat and AC; dumping the heat to one side of the system or the other depending on need, as controlled by the thermostat.

What is the alternative? I've seen in (new and old!) England they use natural-gas radiators sometimes, and have no AC, or window AC units. Is that it, and now areas with those are switching more to heatpumps? Or is it new, more efficient heat pumps? Or do I have a misunderstanding of the existing tech?

The houses I've been through in the Midwestern US typically have forced-air natural-gas furnaces and cooling-only non-reversible central AC. Burning natural gas is way cheaper (ignoring externalities) to generate heat than even a heat pump, and can be easily scaled up to provide tons of heat on really cold winter days. Plus, modern heat pumps are high precision, complicated, expensive tech, a furnace is old tech: just a burner and a blower.

My natural gas cost is $0.82/CCF or $0.028/kWh. Electric is $0.161/kWh. That means a heat pump needs to be 575% efficient to break even on energy cost (assuming my furnace is 100% efficient, it's not, a lot of heat goes out the chimney).

People only get heat pumps here if they're carbon-conscious.

In my area in the midwest, nearly every house has a natural gas burning forced-air furnace for the winter and a standalone air conditioner for the summer.

Newer heat pumps have gotten a lot better, and as a result a few people are starting to use them here. Even so most heat pumps are the more expensive type that rely on geothermal coils. We have extreme seasonal temperature changes that make older heat pumps impractical. For about two weeks each winter, our overnight lows are around -20F (-29C) and we often see wind chills around -40. Summer temperatures regularly reach 100F (38C).

I would venture to guess that most residential heating in the world is provided by non-heat pump sources.

In many parts of the United States, my understanding is that it would either be natural gas fired furnaces with forced air, oil fired furnaces (with forced air? not sure), radiators (with water heated by gas or oil fired furnaces), or electric resistive heating elements (e.g. baseboard heaters).

UK is almost exclusively hot water radiators heated by natural gas boilers (or oil boilers in rural areas not on the gas grid).

There is a push by government to switch to electric heat pumps driving hot water into larger, cooler radiators (as this is more efficient for the heat pumps), backed by a £7500 grant for the pump and installation (with limited take-up).

Thanks for the info on this! It sounds like my experience has been biased by coincidence. Ie, I've only lived in a house that was wired for gas once! (Northern VA). My childhood home (Also northern VA), both places in North Carolina, and Florida have all been heat-pump based, with no gas line.

My apartment in the UK was even weirder: It had something called a "Economy 10", with an electric heater (resistance?) in a concrete slab under the floors that would run at night, then release heat slowly throughout the day. (No A/C)

In the US heat pumps have only seen widespread adoption in the last decade or so and even then mostly in new construction applications. Most houses still use either window or central AC units and then some other mechanism for heating, oil or gas furnace, electric baseboard, etc.

>If I save 60% on energy for heating every year but then require all the energy needed to build a new heat pump every 5-10 what am I really doing?

>As good quality as your normal store bought air conditioner. That is to say, as soon as something goes wrong with them, they are garbage.

Sounds like you're still saving 60% on energy because the status quo is also disposable appliances. It absolutely sounds better than nothing to me, but I am also hopeful for more maintainable and accessible heat pumps in the future. I haven't heard about any efforts for an open source heat pump, but I'm definitely interested in something like that myself

Where are you seeing this? Mini splits have been in use for a long time and just about all cheap brands are rebadged Gree and Midea, which are reliable and in use all over Asia.

IMO, the problem is that HVAC companies in the US overcharge so much for install/labor that homeowners are more inclined to replace them. They won't touch mini split brands that they don't install (and generally only install expensive brands)

Quality cones with design refinements learnt after the technology has been in people's homes for decades.

There is nothing theoretically unreliable about a heat pump - it would totally be possible to design it to work for 50+ years with just basic filter replacements.

> store bought air conditioner

Yup. Saving the world is going to be ruined by Chinese shovelware-quality equipment re-stickered with American brands, but in this case it's even worse since you're hiring a professional installer and those guys will only work with a short list of manufacturers, so getting somebody to install an expensive quality European model will be basically impossible (if they're even certified for use in North America).

Asia has been using mini splits for at least 50 years, Chinese made units are reliable, and the expensive brands are generally made there too.

China has been making lots of things for 50 years. Experience doesn't matter if North American "manufacturers" insist on importing only the the most disposable low-quality products.

> If I save 60% on energy for heating every year but then require all the energy needed to build a new heat pump every 5-10 what am I really doing?

Activism.