Heat pumps!

Severe post necro, but... I found the heat pump videos when I was looking to calculate the break-even versus my propane auxiliary. Fantastic content - and, you've given me a great idea for the mini-split in the garage instead of going with propane out there. My local co-op has been starting to call out "cold climate" heat pumps (which I wish I had been told about when I invested $4500 in an air source heat pump last year) and a cold climate mini split might be a great way to keep it defrosted out there in the winter. Otherwise, the whole-home unit is doing great for my northern Minnesota home. My dumb-but-allegedly-smart thermostat has been manually set to cut over to propane at about 5F, which appears to be the temperature at which the ASHP can no longer keep up with the house's thermal losses.

Heat pumps have been the main source of domestic and commercial heating in NZ for years now...Just a shame that the majority of homes are still single glazed and not sufficiently insulated.

I’ve been following Nate over at http://www.natethehousewhisperer.com/ regarding heat pumps and also the electrify everything movement. I’m having a house built and had to ask about heat pump options, and was able to have one installed in central IL, but I would not have been given the option unless I specifically asked about it. Paired with enough solar PV generation, to me it seems like a great way to condition indoor space for much of the year. Love the videos, thanks for making them!

KM

This was an awesome video. I had no idea that electric heat was getting so advanced these days. Being in Canada, I can't see this taking off a lot here until we get those versions you mention being better in really cold weather, like geothermal based. I feel like this could be a big part of going zero emission.

Matt

In this setup the device uses the building as a "heat bank", that it constantly deposits, and with a defrost it makes a small "withdrawal". All in all it deposits more than it withdraws, but wouldn't work in an environment where it gets cold instantly after switching off heat. There are some Panasonic "heatcharge" devices that make this excess deposit inside the outside unit, and use the energy stored in the device to defrost the outdoor unit. No pause in the heating is necessary. This comes with a price though, and the price difference in here atleast was almost 1000 euros. No point in paying that, I figured. BTW our Panasonic heat pump is promised to make heat up to -35 C. This winter it was only -25 C outside here in southern Finland, but inside unit still easily heated +21 C inside air to around +45 C. Regarding efficiency: a heater is more efficient when the fan blower is at max speed. This is, to my knowledge, because the temperature of the refridgerant can be kept lower and still achieve enough watts of transferrer heat. In Panasonic heat pumps this economy mode is called "Powerful" mode. It works with manual fan speed too, but the machines usually limit fan speed because of "drag" created by the moving air, thus impeding efficiency in normal operations. This is because some people might not like how +30 C air feels on their skin (it would feel a little cold, yes). I agree about the reversibility of air conditioners not being a standard being a sad thing. My electric car Seat Mii has AC, but heats with 1:1 PTC elements in the winter, thus reducing range. Great video! It was interesting to watch. About the humidity: it might be a good idea to get the roof water to drain properly in a stormwater drain. Just dripping randomly without down spouts (or whatever you call them) creates good conditions for mold since it keeps the ground near building very wet! Same can be said for the heatpumps condense water, but not that much (although I'd still collect it to a bucket and dump it somewhere not-near-the-house).

Juhani Saarinen

More efficient than getting heat from the comments amirite?

Stephen Gillie

BTW, the wall mount units (PIONEER in your picture) is extremely common in Asia, especially in space limited Japan.

Joe Kudrna

Air conditioning heat pumps are cool (literally), but a water heater pump is better! Imagine cooling a house and heating your water at the same time!

Joe Kudrna

Any thoughts on the experimental technology of gadolinium-magnetic refrigerators?

Stephen Gillie

Check out masssave incentives/rebates!

Jake K

Just in case it ever comes up in the future that you end up making a second heatpump video a great example of a heat pump working in both directions is a cheap-ish ice maker. (IE: https://www.ebay.com/itm/-/353124896282 ) These will run in "normal" mode to make ice, then will click the reversing valve over to melt the ice off of the tray causing it to drop into the bucket.

Johnathan Chamberlain

My mother is a heat pump specialist in northeastern Indiana. More specifically, geothermal heat pump specialist. Loving the refrigerant content and especially the heat pump stuff. You should really blow peoples minds and tell them they can get heat year round from their pond.

Seth Hensinger

Our house, in Alaska, was built with an air source heat pump as the primary HVAC in 1980. It had a 100amp circuit for backup resistance heat and had a load controller circuit to shut down the stove, water heater, and dryer circuits when the backup heat turned on. The 2nd owners replaced the appliances with propane and the heat pump with an oil furnace. We went back to electric but went with a ground source heat pump this time - it’s great! The biggest problem is finding contractors to make it work. Each individual part wasn’t hard, just getting the whole thing done - we ended up doing our own general contracting (and a lot of the work). If you need any photos of the installation or of a drill rig in somebody’s yard, let me know.

In part 2, would you be able to mention how a heat pump is different to a heat recovery unit?

I've got a whole house "Air-to-Air" (as the local HVAC guys call them) heat pump down here in Florida, and it has a 2nd heating stage (labeled Emergency heat) made up of resistive wire heating elements for those colder days when the efficiency isn't quite there (of which there are around 10 per year). Back when I lived up in Michigan, I had a natural gas powered furnace. Adjusting for square footage, I would say I pay a similar amount of money each year for HVAC per square foot, but this was before Natural gas became super cheap. I'm not entirely sure what that natural gas bill would be now. As far as the efficiency goes, I'm sure the air-to-air heat pumps (especially the one I replaced the last one with) are more efficient.

Brendan Meteer

Unfortunately, the new house we are having built in Albuquerque New Mexico does not come with an option for a heat pump.

Ron Oakes

Possible input to the follow-up, or just a related piece of information: In the 1950s and early 1960s, my mom worked in The Solar Building in Albuquerque, which was the first solar heated office in the US (or world) for the engineering firm that designed it as an architectural engineer. She has described to me how as a backup to the solar heat the original system would use the heat from the municipal water supply to heat the building. I don’t know the details, nor know if she knows or would recall, but I’m sure some sort of a heat pump was involved since the municipal water here isn’t hot. The Wikipedia article on The Sims Building in Albuquerque indicates that it too originally used the municipal water system as its heat source, which was designed by the same engineering firm, but before my mom worked there. Alas, both systems have been replaced with more traditional systems.

Ron Oakes

When I had to move last summer I was pleasantly surprised to discover that my new apartment has a heat pump. Yay!

tim1724

Yay heat pumps! It is fun to have a place right on your yard where you can be in even colder environment than ambient around you. During summer if it is not hot enough, just go standing in front of full ac with full power.

TIL there's such thing as a heat pump dryer! I went down a bit of an Internet rabbit hole on that topic. Seems to be similar to the concept of a dehumidifier but for extracting moisture from clothing... Fascinating!

As someone looking to move from natural gas to a whole home heat pump right now (in MA), the timing of this could not be better. Another fantastic video, can’t wait for part 2!

I'd gladly watch 40 minutes episode about "rendering hell" as it's a place I've been to too many times myself.

Cool! (But I'm not seeing captions besides the auto-generated Portuguese (!) captions from YouTube. Did you definitely publish them?)

Tuesday M

Though I missed the initial pre-release, I thank you for toning down sibilance stuff since I'm usually a little sensitive to it. Sounds great! Another superb presentation. Cheers!

Alec Jahn

That's really weird! I'll fix it.

Technology Connections

Omg that t̶h̶e̶r̶m̶a̶l̶ ̶c̶a̶m̶e̶r̶a̶ thermographic* footage in parallel with your explaining it is perfect 🚀 Well done 👏🏻 * yes I had to Google it ** video on thermographic cameras please 😅

Dave Tapley

Heyo - the hyperlink in this post is still going to the old upload 😄 (you can copy and paste it - that’s right, but clicking the link takes you the wrong direction)

Aaron Carson

Hey! Now I know what the "Em Heat" on my heat pump thermostat is for!

illves

05:32 Latent heat is absolutely something you can feel directly. Lick a finger and stick it in the air on a windy day.

There was a slightly jarring jump cut at around 32 minutes. I actually rewound and made sure I wasn’t seeing things

Adam Zawisza

CO2 could be the refrigerant of the future. Sanden makes a mini split hot water heater that uses it. It has the added advantage of using something that can be extracted from the air as it's refrigerant.

Adam Zawisza

I really enjoy these explainers. Thanks for doing them :)

evistre

A cool way to demonstrate the refrigeration principle is by releasing gas from a pressure vessel (such as hair spray, deodorant spray, or the propane bottle while using a gas-powered BBQ or patio heater) and noticing that the vessel gets cold as pressure is released.

volty

A ground source heat pump would be better for your area.

Adam Zawisza

I was wondering after watching if a hydrophobic coating would help with the defrost frequency, or if it would act as an insulator on the evaporator, and I found this helpful paper: https://www.researchgate.net/publication/305180722_Impact_of_a_Hydrophobic_Coating_on_the_Frost_Buildup_and_Defrost_Performance_of_a_Heat_Pump_Evaporator

Ah, well thank you! I didn't look deeply into whether there was a TXV or not because in chatting with the person who provided that great footage of the demo rig, they had asked their instructor for me whether there was something different about the metering device in reversible setups and their reply was that for ordinary household stuff it would usually have a cap tube and so no. Since this minisplit was frankly much less expensive than I figured they'd be especially with the inverter compressor (it was just over $1000 shipped, though I did the install myself) I found that to be corroborative. I'll pin a comment with some of this info. Regarding the efficiency, you're right that I made it sound as though the need for defrosting was the only reason for efficiency drop. I should have worded that more carefully - in fact and aside I should have included was that on the -10° day, it really wasn't defrosting at all because the air was very dry. That didn't help it any, though!

Technology Connections

You asked for a correction on the matter of the expansion device, so I'll deliver :) I believe your unit most likely has either a TXV (thermostatic expansion valve) or an EXV (electronic expansion valve) -- most mini-splits seem to have those. Also, it likely has a separate one for cooling and heating! Conventional units have a cooling expansion device inside and a heating expansion device outside, but I think I've read that mini-splits sometimes place both outside (to reduce the whooshing noise you might otherwise get at the indoor units.) There is one thing that I see everywhere about the newer cold-climate mini-split heat pumps that I have to complain about... many people say that newer models retain their _efficiency_ in low temperatures. This just isn't the case... rather, they use tricks (like raising the speed limit of the motor in cold temperatures) to maintain their _rated output_ in low temperatures. Certainly they are more efficient than the old ones, but their efficiency still drops dramatically in cold weather, and they consume more power for the same output. This also isn't just due to defrosting -- all heat pumps lose efficiency as the temperature differential between source and sink becomes greater, defrosting is just the "icing" on the cake.

Having lived through the outage in Texas, it was no advantage to have natural gas heat, since the hvac system required electricity to operate. I retreated to my Prius Prime in my garage which utilizes a heat pump for both heating and cooling. It kept me warm for a few hours before the traction battery depleted.

Eric Kalenak

This is really interesting. In our last house here in the UK the only source of heat we had was an air source heat pump that was used to heat water in a tank which then went off into our traditional wall mounted radiators and also gave us hot water. However this mode of operation was entirely one way, air conditioning is incredibly rare here. So, one winter was uncharacteristically cold and what was the result...a frozen air source heat pump and no heat and no hot water with absolutely zero way to fix it. So it seems here in the UK we have got the exact opposite problem to the states. We only use them for heat and that comes with major issues in itself if the ambient temp outside drops below a certain point. In our new house we are even more old school burning Kerosene delivered to an external tank by truck fed to our boiler. We’re realising that this will become unsustainable in the not so distant future and so heat pumps are on my mind again. Thanks to this video I’ll be making damn sure there is some form of frost protection.

Tim Hugall

I’m definitely interested in looking at this kind of thing when we need to replace our furnace or air conditioner. The furnace is getting up there in age after all. But being in rural Minnesota, it’s hard to wrap my head around this working for us. We just spent a full week below 0 F when Texas had their cold spell, and we approached -30 multiple times. I know that’s the “but sometimes” thinking, it’s just hard to really grasp something like this when my whole life has been heated with propane. We don’t even get the option of slightly more efficient and convenient natural gas around here.

Stumblr

Another great vid! Learning heaps about the various things around my house. Here’s an idea you might find of interest. Can you talk about those tube delivery things you find at the bank that work off a vacuum? I always found them fascinating growing up.

David Cichowski

In the UK my local council (city government) has started installing in social housing, non-reversible air source heat pumps that heat up water tanks that feed radiators. It's a strange system but the UK government is offering financial incentives to use heat pumps but only if they heat up water and not air

Excellent and comprehensive - even for us here in the UK. Can't wait for the second part ;-)

Nigel Brown

My air source heat pump works well in an outbuilding almost all year round here in Gloucestershire, UK.

Peter Bryenton

Aaand now I want to replace my aging AC unit with a heat pump!

I'm up in Toronto and recently upgraded to a reversible mini split. We're on gas, so I really only ever thought of the heating feature as a weird bonus. Thanks for showing me the error of my ways. Stupid question: since heat rises, does it make a difference that the units are high on the wall?

Buckaroo Bunny Slippers

The Alaska SeaLife Center shifted most of its heating from (probably) natural gas to a CO2-based heat pump a few years ago. It uses ocean water as the source of heat energy. Might be worth mentioning in the next video. https://www.alaskasealife.org/news_item/34

Quinton Wilson

Great video, Alec. When I remodeled my house some years ago, we considered small heat pumps for each of the 3 levels of the house (with the remote unit located on the flat roof). We ended up going with hot water radiant heating in the floors for various reasons (mainly, not wanting to have to consume space for ducts, and that here in San Francisco there's maybe a total of 5 days a year where one might want AC), but I remember being blown away by how much the heat pump technology had improved since I'd first learned about it in the 80s.

Jason Thorpe

This video was 100% worth the "wait" for it. I've been wanting to get a Geothermal heat pump system for my house since before I bought it a few years ago. Unfortunately, there have been a few repairs/upgrades that took precedence in that time but this is next on my list. This video answered several of the questions I had about it particularly about the efficiency I'd see here despite being in NH since the ground temp is typically 55⁰ F at a certain depth in most of the US.

Kevin Maher

Almost all AC units sold here (Israel) for the past 35 years or so are reversible, and an old friend from the USA kept insisting that that an AC can only cool down a home, not heat it, and the idea of a reversible system was beyond him (and I had a hard time explaining it), thanks for helping me feel less like an idiot!

Love this series Alec! I agree with you about the ridiculousness of most homes in the northern US having AC only rather than heat pumps. 10 years ago when I lived in ND and replaced my oil burning furnace with LP gas I suggested installing a central heat pump, but the technician talked me out of it as it would cost more and heat pumps had a higher failure rate. This is a real obstacle to converting our living and working spaces to more energy efficiency--the high cost of the transition. More so when you consider ground-source heat pumps.

Mark Hesse

Ah, but this is "but sometimes!" thinking. And also a mix of poor system design. If I were to install a heat pump, I would make my backup system a gas furnace and not electric heat. Then I could have the best of both worlds. Because that's the thing; it's not that they "don't work" it's that /on occasion/ they don't. But who's to say you need one system to take care of all needs? Besides, recent advances in air-source heat pumps mean they absolutely can work as the sole system in Northern climates (though not necessarily as the most cost-effective option), and that's before we get into ground-source heat pumps!

Technology Connections

I went to my local community college! They're great! I wish more people would consider them. There was a definite push from my teachers and guidance counselor to have "the full college experience" but I am /certain/ that would have resulted in a worse education. In fact, when I moved to a university to finish my bachelors, the classes were literally all worse than what I had taken at my community college. All of them. I only really cared for one professor and his classes were hardly serious.

Technology Connections

This is something I want to address in part 2. I've been looking at videos of "conventional" heat pump systems and their defrost cycles largely seem, well, dumb. The way the mini-split handles it seems best. It should stop before reversing, but many units seem to just slam the reversing valve *while the compressor runs* which makes a tremendous racket. I sort of get that pre-computer controls this was easier, but it seems like a problem that should have been fixed long ago. It's a huge nuisance that doesn't need to be there.

Technology Connections

Heat pumps just don't work in northern climates. My parents tried it from 1970 to 2010 or so.... it kept having to resort to the inductive coils. ie: emergency heat. They finally gave up (after 40 years) and got an on-site a propane tank to supply the heat. They also keep a wood stove running during cold months.

Nate D

For a title, how about "Heat Pumps Are Cool (Or Hot. It's Complicated)!"

James Lynch

In the Netherlands, the Dutch Railways found out that after refurbishing their Intercity trains from the 1980s they saved a lot of energy, calculated on the whole year, by installing air conditioning. The air conditioning units used more energy in summer than the old ventilation, but the less drag caused by the new windows and the energy savings done in the winter by using the air conditioning in reverse mode created a total energy saving.

MrHammond

FRCC was my first alma mater! It was very good (and affordable) preparation for higher level courses at university. You'll likely get more attention & engagement from teachers at a community college than at a university for 100/1000 and 200/2000 level classes, and for what it's worth I'm talking about math (Calc II, III and diffEq) and engineering courses, not just liberal arts (but I found the trend there as well).

Jeremy

Oh that joke left me cold.

juenger1701

This one left me feeling cold.

Kris Pockell

When The unit does the defrost (makes that reversing sound) and a huge steam cloud is ejected, people call and say ,"My motor just burned up, so I turned the unit off !" You try to explain, but it's difficult

My apartment dryer is a Miele heat pump dryer. It runs on a 120v outlet and it is ventless, two things that are impossible to find with any other tech.

I feel like every hotel room had a single-unit reversible heat pump heater/AC, in a certain era of construction

Stavro

Probably a different microphone. He could adjust with an equilizer, but that might require reuploading.

Warren Garabrandt

My parents installed one of these in their house in TN. The reversing valve makes a sudden and very loud hiss, sort of like a semi truck's pneumatic brakes, whenever it kicks off the defrost cycle. The first time I heard it I though the thing had exploded.

Emily Elam

Have been looking forward to this video. Now looking forward to part 2 (and 3?). So if I understand correctly, for cooling a home a heat pump is no better or worse than a traditional air conditioning unit, but for heating a home it can be between slightly better (for those who have natural gas heating) to significantly better (for electric heating)?

Don Eitner

Did you do something different with the audio for this one? The sibilance is a little harsh in some scenes. Apart from that nice video!

WizardTim

Right!

yaaaas. just what I needed to finish off my Friday night

John Dye

Yes!!

I am so pumped for this one.

Jerame Edwards