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SOMEONE CONTACT TECHNOLOGY CONNECTIONS RIGHT NOW!!! Edit: Y'all, the running gag is that Technology Connections keeps circling back to heat pumps.

The whole heat pump conversation (especially resistance to them) is fascinating to me because we have been using them in Virginia for decades. I'm 43 years old and every house I've ever lived in has had a heat pump. I only recently found out that heat pumps are not the norm everywhere else.

Our heatpump is a normal non cascading pump using the groundwater as heat source. It has a COP of 5-6 over the year and heats our water up to 60°C and works for almost every outside temperature because the groundwater temperature doesn't fluctuate that much

AC units should be heating our water Edit: The waste heat from when an AC or Refrigerator is running, should be routed to and recovered/stored in the hot water heater

In the early 2000s, a company called Hallowell International based in Maine developed a '2-stage' heat pump that did pretty much this exact thing. It had two different compressors as well as a heat recovery loop which would divert friction heat from the compressors into the refrigerant in heating mode. We had one of their systems and it performed very well, able to heat our house for about the same dollar cost as the gas furnace it replaced, which was unheard of in 2006! (We're in snow country, and it definitely gets cold here.) Unfortunately, the company didn't survive, mainly due to quality and durability issues with their control boards. Our system eventually died from a bad control board, which we couldn't replace. We ended up replacing it with a variable speed drive heat pump from Amana. Its good to see people are still tinkering with the concepts though!

This is how freeze dryers work. They have to get the internal temperature down to about -40F, which is too much for a single system to handle. So you use them in tandem to create a greater difference in temperature.

I'm a manufacturers rep for hydronic equipment, and part of what we do is design and sell Air-to-Water Heat Pump systems for radiant heating and radiant cooling. And we need this!!! Looks like it will have built-in buffer tanks, and can cool to pretty ridiculous OA temps. Depends on how big they will be....but I'm looking forward to seeing them in the future. Thank you for all the entertainment!

today the temp is over 42C inside and outside it is over 44C here in India. Traditional air conditioners can't handle this load- We had power blackout twice today. Two stage heat pumps must become cheaper so that it is affordable.

you know your an odd ball when you see "the prefect heat pump" and get excited. lol love your show broski.

I used to work on controls for cascaded refrigeration units for use in medical and scientific applications. Once you have a second stage, it's pretty crazy what kinds of temperature gradients you can have. IIRC, one of them I worked on was a -150C system. Heat pump is love. Heat pump is life.

Thanks for sharing. My heat pump units are nearing end of life. Great to see options for replacing them.

Thanks for taking the time to put this together Matt. Did you happen to see how this worked in conjunction with thermal heating and cooling? Was that even an option? With this type of cascading heat pump?

I always wonder if technology outside of the nordic countries is outdated or do we have some well kept secrets, because we simply have much better heat pumps that work very well in our very cold winters. For example this year I had one installed at home (Mitsubishi RW-35) which can keep a COP of 4 at temperatures as low as -35C (-31F). It's not a cascading heat pump, but just a regular one. A have another heat pump installed *15 years ago* which can keep a COP above 3 at -25C (-13F)...

We use cascading systems for negative 80 Celsius. Freezes and negative 20 Celsius. It's the same principle we just taken multiple little compressors with different freons with different glide and boiling points. I'm just staging them and using the medium. From the fluid as its transfer, instead of the air outside

Superheat can be addressed by an accumulator it adds volume of fluid. this is done on refrigeration systems for food service where it has to operate in the winter where returning refrigerant has a large amount of liquid with the gas. The accumulator stores the return fluid and gas mixture in a tank filling from the bottom and supplying gas from the top of the tank to the compressor. There are sensors that detect if the liquid in the tank is to high.

We are going for a geothermal Heat Pump (with floor heating) and passive cooling for our new house. Pretty nice as the temperature of the ground is a stable 3-4c and that means the COP is like 4 year around. Its also much more quiet than air-to-air heat pumps and does not need to "de-ice". In the summer we can use that "cold hole" to passively cool in the summer.

We have 2 air source heat pumps, about 10 and 6 years old, on our home. We live in CT these days and oil is our primary heat source. We have consistently saved about 1/3 to 40% of our oil usage for heating, thus saving hundreds of gallons of oil each year while saving money, as the net cost of electricity is less than the oil for those BTUs. I am an engineer, and compare our oil cost * efficiency of our furnace to our heat pumps and electricity costs. It's a no brainer for saving money, and we still have the oil for days below about 30F. 25F to 40F roughly, depends on the oil price and electric price that year, is our break even point.

Thanks for sharing Matt. 👍🏻

TY for the VOD. 👍👍

yo dawg, I heard you like heat pumps...

Awesome video - I am totally geeking out on this heat pump!

This is definitely something to keep my eye on, for when we expand the house. Right now we have window units (cut through the walls, rather than stuck in a window) in each area of the home. This has had the added benefit of individualized temperature control.

This was mind blowing and super interesting. When my AC unit starts to fail on me I will be switching to this for everything!

I will be installing a closed loop well source to cool slabs in summer and feed a heat pump for domestic hot water & to keep slabs warm in winter. The cascading system would be good for boosting the slab water up to the domestic hot water temp, I may add a second smaller heat pump fed by the return water from the slabs in winter. Thanks for the presentation, it got my thinking cap on! I am about 200 miles north of you Matt.

I'd drill a bore hole and go with ground source heat pump. No need to be able to extract heat from -30 C air when the ground is a constant 8 C.

We should have an integrated modular heat pump system that is able to accept multiple heat/cooling consumers and intelligently manage the heating fluid depending on what needs heating and cooling. So you'd have one box (attached to an exterior radiator) which would have multiple hoses snaking off to every device needing heat management which would report what they needed and the unified heat pump would work out what fluid to pump where at what parts of the cycle.

Thank you… this video was perfect timing. I’m currently looking into replacing my 14 year old HVAC system and wanted to replace it with a heat pump. I will go look up this company.

thank you for well thought out tutorial and clear presentation ... so much better than most in my opinion of course ,,,

I am over in Albany, so I may have to check these guys out in Mass...

I live in the far north of Canada in the Yukon. Much of the winter is below -35C. Would require additional heating for sure. These heat pump things seem to be getting close though, very interesting. Thanks for all your videos Matt, much appreciated. Keep up the good work!

That's exactly what I need for my next heat pump. It'd let me get rid of my propane furnace backup without upgrading our electrical service to have enough room for heat strip circuits. Our current Amana 20 SEER air source heat pump does alright down to about 5-10F, but it's running at a COP of about 1 then and in the Midwest we spend about 15-20 days a year below that. We'd probably have enough insulation to deal with one night of those temps, but it's usually for a whole week when we get those polar vortexes.

I am in TN near Nashville. Here we do get 100+ summers and a few weeks below 0 F in the winter. Our house has a heat pump but with a resistive 'heat kit'. Nothing we have, even our EVs use electricity like the Heat Kit (resistive heater that de-freezes the heat pump). We stil have people that tell us that 'heat pumps don't work below 32F' and other such drivel. When we need to upgrade our heat pump in a few years I would LOVE to have anything near affordable heat pump that really works! Heat pumps in our area tend to be 'package units' that sit outside the house that includes both 'inside' and 'outside' portions of the heat pump and our return and conditioned air ducts got to the unit that sits just outside our home, this make a compete 'hvac package' (and it sits on a small slab just outside our home, with ducts in our crawl space).

In my neck of the woods temperatures range from -35 to +35 degrees Celsius and since there not being many heat pumps that can handle the low temps insurance companies mandate that home owners must have another source of primary heat. Flooid's cascading system definitely got my attention.

Nice. I am looking at replacing my entire heating/cooling system. Just got a 15kWH solar system with tesla power walls. I live in New Mexico in the desert mountains at 6500' of elevations and it gets well below 0F and 100F. In Fact in the summer it can be 40F at night and 95F during the day.

Very timely and intriguing presentation. I hope I might be able to make use of a Flooid system in my home and at my office building. Thank you.

Definitely paying attention to this! We live in Minnesota, where -20f is not unheard of and -10f happens several times each winter. This could give us a heat pump that is highly efficient even in our coldest weather.

Thanks Matt. A cascade heat pump is just a scheme to get a heat pump to work at all in very cold climates and is not about increasing efficiency. Cascading systems can get heat out of extremely cold air, but the quantity of the heat you get (BTUs) is on the small side (i.e., super cold air does not have a lot of heat content, a very rough analogy is an alternator coil which steps up electrical voltage, but the amperage goes way down). To make the cascade trick work, you need an oversized heat pump at the coldest end of the cascade to produce a whole bunch of moderate warmth. Then the next heat pump can pump/turn that large amount of moderate warmth into the warmth you need for your house. Remember, each heat pump in the cascade costs extra money and the first cascade heat pump, being larger, costs more (need to confirm that the outfit you talked to up-sizes heat pump #1, the coldest one). Why go to all of the expense of a cascade when a ground water based heat pump works better. Extracting the heat out of 55°F ground water means a COP a bit greater than 4.0 on even the coldest days (job done). I'll bet the extra cost of the buried water coils is similar to the cost of the extra heat pumps in a cascade system (need to confirm this). A good non-cascade heat pump, like the Mitsubishi Hyper heat ductless mini-split, has a COP of 4 @ 48°F outside temp & a COP of 2 @ 5°F outside temp and can extract heat from air as cold as -13°F (-11°C), but the COP goes down to ~1 at this temp. BTW - the magic here is mostly an oversized heat exchanger. Costs - High COP only partially translates into dollars saved because the cost of electricity varies so much over the USA. My electricity costs ~17 cents per kWhr (I'm including every cost, like line transmission charges) and my separate high efficiency (95%) condensing gas boiler gas boiler runs on natural gas that currently costs ~12.7 cents per cubic foot (I'm including transmission charges too). The cost cross-over point is 47°F (i.e., cheaper to burn natl gas below 47°F outside temp). About 3 years ago, when I replaced my 25 year old just-A/C system with the Mitsubishi Hyper heat, the gas vs. heat pump cost cross-over point was ~32°F. My Mitsubishi ductless mini-split cost about 2X more than a traditional A/C-only system. I was OK with this because I got two systems in one and every room now has its own zone and I don't have to burn natl gas for about 40% of the winter when the outside temp is 47°F or warmer (min temp in my area is ~5°F). The old A/C was and the current gas boiler based heat is one giant zone for the whole house. Gas heats my hot water year round.

I really think it would be cool to have a home heat pump that has lines that bring hot to things like clothes dryers, water heaters, home heaters and respectively bring cold to Air conditioners, refrigerators, and freezers.

Very interesting, good video. Sounds like similar principles the environmental testing chambers I used to use. A refrigerator within in a refrigerator (two compressors, different refrigerants) to cool/heat as required.

This was great information, and a very well done video, thank you.

Complex systems are only beneficial if reliable. As a home builder that delivers around 300 homes a year… we are seeing a 38% failure rate of hybrid water heaters. We had a 0% failure rate with electric, 3% failure rate with gas and a 6% failure rate with tankless.

Ever since James Watt gave his name to Power there has been new forms of wheels. Homebuilder should stick the the 3 rules: Insulate, Invent and do your bragging last!

Looks like awesome tech. I'm ready to hop on the heat pump train. My house was built in 69', the furnace is from.. 69'. It's a heck of a furnace that literally will never break, but is love to snip the natty gas cord. Once I get solar panels installed it should eventually be a closed loop system.

Hey Matt, I just wanted to say thank you for taking the time to add your own captions to your videos. KZfaq's auto caption feature is borderline broken, and for those of us with a hearing impairment, it's quite frustrating to watch auto-captioned videos. I have to have the video volume cranked up quite high (I wear headphones so I'm not blasting out the house). When massive volume swings happen in videos, you can imagine the discomfort. You take the time to do a volume normalization pass to keep the volume consistent through the entire video. Again, this extra touch does not go unnoticed nor unappreciated! The production quality of your videos is definitely professional level. Thank you for going the extra mile.

A heat pump is next on my to-do list of big projects. When I got my 1st house, the AC unit was already in terrible condition. I’ve cobbed it so it still works, but it’s a Sword of Damocles that could fall at any time… or perhaps more of a Schrodinger’s AC, whose cesium may or may not have already decayed.

Cost and efficiency will determine if this pans out.

Heat the house water and then run the output through the water to air exchanger to make winter home heating. In summer, pump house heat outside and then boost with ambient to heat house water. Sounds great for decarbonising.

somewhat simple, yet so elegant...love taking existing ideas and improving them to make it work vs coming up w/ grandiose ideas that NEVER works....(windmills for example..)

The thing is, if the higher efficiency in those (depending on where you live) rare temperatures doesn't offset the additional cost over the lifetime of the heat pump, it really doesn't make any sense. Like you said in the end, I feel like, unless this sometimes becomes super cheap, it'll be a niche product at best, for when you live in a super cold region.

The explanation was not very clear. A COP graph would have been more informative than examples given.

Thank you for the commentary.

Matt never fails! Great information! 😊

Glaring problem with cascading heat pumps: there are only a handful of technicians that can service the system in Massachusetts, and they all work at Thermo Fisher and Shon's.

As a MA resident with an old oil system, I would love for residential cascading heat pumps to be a reasonable option. I'd be curious as to their cost comparison to ground based geothermal systems. As always, thanks for the neat dive!

Innovative. I am impressed with those numbers on efficiency.

Looks like we will be using the Harvest Thermal system for our new home build in NW Montana, thanks to you

The main efficiency 'problem' with our heat pump is not solvable: ice on the evaporator in moist weather with temperatures of 0C to 4C. It then has to defrost every 30-40 minutes. No matter what the optimal temperature for the refrigerant is, this will happen to any unit. I was considering putting a waterproof IR mat on the wall, thus radiating heat to the unit and prevent it from icing up so quickly... but as COP is still around 3 it seems unlikely to be more efficient.

Where I live I don't have heat or air conditioning nor insulation in my home I built out of interior and exterior block . The temps range from 68 degrees F to 89 degrees F. High ceilings, ceiling fans, and openings keeps it comfortable. Coming from S. Florida to the breezy coastal hills in the Caribbean I was surprised after living in A/C 11 months a year for 25 years.

Thank you for another excellent video!

The incentives are probably the reason why the costs are so high. Just like with college, if the purchaser can get "free" government money (that was taken from you in the first place) on something, that means the market can handle a higher cost, until the price once again hits the equilibrium point where the customer is again paying the same cost as they would without government involvement.

As we move from a fire to heat, to a heat pump, to two heat pumps, the capital costs keep increasing. And the potential for needing repairs. ("Parts that aren't there cost nothing and never go wrong." Charles F. Kettering) You can buy a lot of heat strips for the cost of a compressor and hardware needed. Nevertheless, all exciting.

Very interesting, I would definitely consider cascading heat pump. 😊

OMG, what a great system! I just had to replace my 20-year-old heat pump with a new one and can tell the difference. How much better will Flooid's heat pump be! Very exciting.

The main problem with heat pumps is that cost savings on your energy bill won't justify the cost of the system. Especially if something breaks outside of warranty. I think the biggest thing is that manufacturers need to get the price down for heat pump systems to truly justify buying a heat pump

NYC uses the hot air radiating off DJT to heat Manhattan all winter long

I live in southern Australia so min temperatures can get to about -5 degrees C . and up to 45C . My home is only about 100 square meters very poorly insulated. I have installed an INVERTER FUJITSU heat pump. The inverter technology makes all the difference and also instead of an old type thermostatic expansion valve it uses a stepper motor to get much more accurate control of changing the amount of refrigerant from liguid state to eventually gaseous state. We call these units air to air Mini splits and my system is working great. The unit is rated with COP of around 4. My unit is rated at 8000W when input power is 2000W hence the COP of 4. Now yesterday min temp was 1 deg C house temp ranged between 27C to 23C in my lounge room. I do not heat bedrooms or kitchen but even here the room temps range from 16C to 19C Yesterday the temp in the morning was 1C with 85% humidity. What happened was the evaporator unit outside iced up normally my aircon draws 1000W but for about 20 mins unit went into DE ICE mode and drew 2000W. I know power consumption because I have OFF GRID inverters with battery back up. After the deicing unit returned to normal as the day warmed up to 6degC. Yes for the climate I am in these Mini splits apparently will go down to -15C with an average COP of about 2. When I visited the UK in 2018 my cousin who is a gas engineer showed me his installations using gas boilers and hydronic systems. The thing I noticed was that in the UK they virtually heat the whole house. Your Gas is a 1/4 of the price we pay in Australia so I guess they can just use boilers. Looking at this video I was overwhelmed with the massive plumbing complexity of using these heat pump systems. The cost would be enormous . Why don't people in the UK go for using separate Mini Split units that you turn on and off or set temperatures in each room via the hand help controllers. My Minisplit cost $3000 AUS to buy and install. Thats about 2000 pounds UK for each unit, they are quiet and of course they can cool as well. When I lived in the UK in the 1960's people only heated the lounge room and maybe the Kitchen. I visited the UK in 2018 when the Beast from the East arrived yes the homes were nice and warm everywhere through the whole house. Maybe we need to just back off trying to do whole houses and have smaller modern heat pump mini splits

Este canal es increíble, gracias por tus videos!

Have r290 heat pumps reached america yet? They've been on the market in the UK for about a year and r290 is code for propane, they use that as a heat transfer medium and are said to achieve 70C, which also means they can be directly swapped out for an existing boiler. Not cascading as far as I'm aware.

The biggest problem with all this "new" cutting edge technology is that its either completely unavailable to anyone that might want to get it, or even if it is available, its so expensive that only a millionaire or someone willing to take out a second mortgage on their house could afford it. More effort needs to be made on getting costs down, and making this fancy new tech something you can walk into a big box store and buy without financing, and take home and install yourself.

This is a great idea, I would love to see these in Canada

Easiest way to describe it is a bucket chain on stairs. You can't lift a bucket from the ground floor to the third floor as one person, no matter where you stand, because you can only reach so far up above or down below your current level. But with multiple people all on different steps, you can lift the bucket up or pass it down, as long as the two neighboring people share a certain height where both can reach.

Can you add some annotations though the video with celsius conversion? You have some later in the video but not in the middle and earlier bits.

This sounds like it can replace a hydronic boiler system for homes with in-floor heating........very exciting

I'm planning on intergrating my MVHR setup to work with an air-air heat pump in the future, I really wish there were more videos on how to accomplish this, I had to teach myself. It involves a fair bit of clever ductwork, but the idea is to further reduce the load on the evaporator head so that the heat pump has very little to do, either in heat or cool modes. I currently use my excessively over-insulated loft space as a sort of 'thermal battery' and that's what my MVHR unit currently draws air from, so the loft space is one huge heat exchanger. To date, I've never heard of anyone using a passive system like this, but it works extremely well so far. I've had to do this because my ancient (20yr old) gas boiler does not run very well, it struggles at anything over minimum temperature settings and I currently can't afford a new one. Therefore, my focus shifted towards making the MVHR system as efficient as humanly possible. The loft is vented, but it is only an inlet for fresh air. The MVHR unit draws this pre-warmed air from the loft space, boosts the temeprature up and pumps it into the house. Any warm air from the house is sucked into the MVHR unit, the heat is recovered, then exhausted outside. Fitting a heat pump evaporator unit between the MVHR house suction and intake vents only would mean that the heat pump is only accounting for the small efficiency loss of the MVHR unit (curently around 80% efficiency) so the heat pump is only adding in ~20% into the house to maintain a temperature, instead of having to apply 100% of the load. One other thing that I can currently do with my MVHR setup is that I can change the height of the loft intake vent by opening and closing a set of damper valves. This dictates how much air is being drawn into the loft space depending on what season it is. In summer, I open the upper damper so that most of the heat in the loft is vented, but in winter this is closed and the air is drawn in at floor level of the loft (due to heat naturally rising towards the top of the roof, where the intake of the MVHR unit is placed). This effects if the MVHR is drawing in cooler outside air in summer or warmer rising air from the house in winter, I plan to make this motorised and automatically controlled. I'm currently working on a way of adding in a heat pump hot water cylinder in the further future, but ducting this in as well seems to be interesting. The goal is that as little heat as possible is exhausted out of the MVHR unit, while in effect, making an air-to-air heat pump indirectly provide hot domestic water. For a couple of figures, my MVHR unit draws a constant 25W of electricity, yet in it's current setup, it's maintaining my house between 16-18'C whatever the weather outside. Adding in the air-to-air heat pump is primarily to get rid of my unreliable gas boiler, but it's worth using the existing MVHR system to heat the entire house from 1x HP unit.

I would be interested but 1. Getting an hvac guy to install and maintain it would be difficult at best. 2. A DIY system is out as well. (cost to be a certified hvac and all the tools to work on it). 3. Parts availability would be a consideration. 4. The changing coolant requirements of the EPA for the next several years makes it a tough decision on the purchase a new system mainly because of coolant availability concerns. 5. coat vs payback in terms of years. What would it be? 6. if the systems last more than 20 years coil cleaning becomes key. Are the systems easy to access for cleaning?

Makes me sad, in Minnesota can get below -40C/F on freak days so it still doesnt work

I have often thought a cascading system using two separate heat pumps makes the most sense; especially for people with their own solar. Essentially, stage one is a heat pump that stores heat (or removes heat) from a huge thermal battery (pond, pool, sand, etc) whenever there is excess power generated by the solar array. Then another heat pump uses that battery as its source to heat or cool the home. Its a two stage cascading system, but there is a thermal storage element that allows you to maximize the value of your solar system, and avoid pushing your heat pumps out of their optimal operating range.

well i ll probably need one next year, i would be really interested by then. in nothern canada where the winter is betwen -15c and -33c regular heatpump isn't up to the jump, but that cascading system got me quite interested

I heard - 11 and went " My old heatpump goes down to minus 20 C, that's not impressive." Then I remembered that the US still uses the old measurement systems, os it's around the -25C. Still not that impressed as we have - 35 C pumps here now too, and - 25 is almost the new standard.

Hi Matt! Right now on the Green Building Advisor website there is an article by Jon Harrod about the Ephoca Cold Climate Heat Pump which doesn't need an outdoor unit. It can mount on the wall or ceiling and you can also get it with an ERV included. There is also video from Taitum Engineering about the unit on this site. Have you heard of them before?

It's a shame these aren't available now as I'm building a new home and would definitely consider one.

We need some standards with all this computerization and small companies of varying risk profiles. Imagine a vendor of your $14K system goes out of business then a logic board burns out. Oh, no! I smell a ground-source in my future with an analog control circuit, but I do hope the tech continues to advance!

Congratulations on including degrees Celsius. (The US is "inching" its way towards the SI system that the rest of the world uses.) But rounding the 'C figures, converted from 'F to whole numbers (e.g. 40 rather than 40.3) will make a simpler and clearer presentation. (Bear in mind that most of the figures provided in 'F will be plus or minus some wiggle room anyway so rounding is perfectly valid!)

That seems like an interesting Idea. Something I wondered about though is having a heatpump with the air drawn from something like a greenhouse during the winter so the air is being heated a little as it passes through. Obv won't work all of the time but sometimes the sun does shine in the winter and would raise the temp a few degrees in a greenhouse.

Especially in places where it gets well below freezing regularly. I think you always need backup heat! No matter how efficient the pump is. Heat pumps are Rube Goldberg machines compared to a simple furnace. Complexity = more things to break. When do things normally break? When you're putting the most stress on them, which also happens to be when you need them the most! So, always have backup heat!

Unfortunately based on this channel's past videos, you can never tell whether Matt is simply parroting unsupported marketing hype. I wouldn't even doubt if he was getting paid by these companies to produce the content to raise the technology's profile for investors. Matt doesn't seem to bring an independent evaluation or critical eye to any of the claims the manufacturers make. He doesn't address a single one of potential obvious downsides of having multiple heat pumps in a cascade- for example, many people will be familiar offhand that large buildings with chilled water systems usually have multiple chillers of different capacities to address varying load requirements. For example, a small output chiller, a medium, and a large, and they can be used in whatever combination to produce the required chiller output. Similarly, as long as you were undertaking the capital cost to build multiple heat pumps, is it really most efficient to run them in a "compounding"/"cascading" system, rather than running them in parallel to optimize loading? That would be my very first question, since those sorts of parallel systems already exist and are common, but it apparently didn't occur to the Undecided production team.

I still don't understand what the "secret sauce" is. Packaging old technology in a new way? It feels like building the system, customizing the configuration based on the climate, would be a most cost effective approach rather than trying to stuff all the components into a single box. What if I only need 1 heat pump stage but the box has 2 or 3? What if I need 4 stages but the box has less? I'm sure they are designing the "box" to fit as many environments as possible but increasing the operating envelope has to increase system cost. I think most people really don't care what goes on inside the box, they just want it to heat and cool for the least money possible. Thanks for the vid!

It gets to be 117f while it is raining here on the gulf coast. I am planning a rain barrel/geothermal loop to add to my existing air to air heat exchanger. The colder than air water will come off of the roof, and when it runs out it is no worse than it was. When there is water in the rain barrel (or drainage ditch in my back yard), I should have a much higher COP.

Hi Math, I am very happy that you started to speak about this. Have you ever heard about geo-thermal Kalina binary system? It was discovered by the Russian scientists. He has used two cycles of two different fluids to improve the efficiency of the geothermal sources using ammonia in 1970. Until now it is the best system to use natural energy. This system could be used in the residential scale. 😊

54°C is "extreme temperatures"? Modern European heat pumps can handle up to 70°C, at operating temperatures down to -15°C. And the COP of those heat pumps also don't sound really impressive. So I don't really understand what's the big deal here.

Heat pumps work in cold weather, but they are expensive as hell to run most people find that out the hard way

Learned a lot from this video - thanks! :) I didn't know that heat pumps actually had an upper temperature limit as well. We (very) occasionally get 42C summer days here in the Canadian prairies, which I didn't know was so close to the heat pump's upper limit. Our 3.5 ton ducted inverter HP has had no problem maintaining a 21.5C indoor setpoint without showing any signs of stress, but I had no idea it was so close to the limit. Bonkers! Perhaps I should ease the thermostat to around 24ish on 40+ days just to give the poor thing a bit of a break.

Installed our ground source geothermal in 1996 with a COP of about 3.2 for heating and about 30 for cooling. It eventually sprung a leak, so we put a whole new system a few years ago with a variable speed drive and much bigger field. It has a COP of about 3.4, but it probably higher since it can run at partial load 99% of the time when it's above 0 F. For my new house, I plan on doing an air source heat pump, but the COP is probably going to average around 2.5 for heating. But it will be much cheaper for the initial cost than the geothermal.

Great idea. Good luck to these guys. To my mind spend time & money on the control system which keeps the two heat pumps in balance. This is a game changer.

I’m in Michigan and I use heat pumps in finished basements along with heated a cable in the bathroom floor. There’s nothing better than that. Carrier or Mitsubishi that rate there units at -22deg. I’m looking forward to theses cascade units in our future

I would love to have a system like this in my home!

I’m pumped. Thx

They should build cascading heat pump technology into a 110/120 & 220/240 volt line of heat pump window units. When the cost comes down. Would greatly reduce installation cost & eliminate ductwork, and the inefficiency of pumping thru ductwork. Plus many houses, ours included, don't have & can't accept ductwork. So window units are the only thing possible. Also, multiple units introduce heating/cooling redundancy, which eliminates one central point of failure. You can just put fans in doorways till any failed window unit gets repaired/replaced.

Thank you.