R290 tweaker-friendly heat pumps in the middle price category. What to choose for 7kW load UFH house? Why are certain nations users choose differently? Vaillant, Samsung, LG, Panasonic

Hardware Heatpump
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Thanks for having me in the forums! I am glad I can be a part of this team, learn and ask for help here! Thanks for the patience reading through my first post!

I’d like to ask your opinions on monoblock/hydro split heat pump alternatives in the 9kW nominal capacity class. Primarily thinking about the original worldwide brands, not niche local products Like Grant, Buderus, Lambda, etc.

I am reading many homebuild/enthusiast heat pump forums constantly, and I can see some different characteristics of each community, that is why I have Many-many questions.

For example, in Germany/Austria (Heizungsforum,Photovoltaik Forum, Haustechnik Dialog forums) usually Panasonic and partly LG is the mainstay for the heat pump monitoring, tweaking and homebuild community with Heishamon.

Here, and in the UK(OEM Forums, Buildhub forums) somehow Vaillant is very common, maybe Samsung along with rebadged "inland” brands, like Grant. Why is that? Why I can see hardly any Panasonic or LG ThermaV forum posts here?

I am in search of a near-perfect, or should I say least-faulty ASHP for our newbuilt detached house. It is about 157sq.m with triple glazed windows, full insulation, and poroton brick construction. Two heating engineers proposed 5,9kW heat load (at -15°C) and 7,8kW(at -15°C) depending on the airtightness and assumptions of the construction quality, so the real value might be around 6.5-7kW. It gets that cold for 1 week at max each season.(Hungary) I plan on installing a monitoring solution, but I am not decided whether it will be Open Energy Monitor, or normal Home Assistant solution. I’ve spent around 8-10 months reading through all forums and datasheets, review threads.

My problem is that every brand has some quirks described in the near fanatic monitoring community.

The Panasonic (L Series) 9kW model has poor defrost capability with too little heat exchanger area for this performance level, thus frequent defrosts.

The LG R290 models have a very capable hardware but documented sh*tty control algorithm, not following weather curve, harsh start, fan speed sticking in high revs, quiet mode control errors, flow temp hysteresis errors, etc.

The Vaillant is less documented(at least in german forums), with many supporters of the “energy integral” control method, but many say it is quite loud in cold continental weathers, with not impressive cold performance. Its modulation ratio, minimum constant output, COP at minimum frequency is hard to come by, also, Home Assistant integration is not as developed as Heishamon for example.

The Samsung EHS Gen7 R290 is the last contender, it has the highest noise figure in datasheets. It is less documented, too, but has the nice NASA tweaking ability. The 12kW model also has a very nice 2.5kW thermal minimum constant output, albeit with weak COP. The 8kW model has surprisingly small chassis, I can hardly believe it can handle 7-8kW loads with low noise in winter.

I know there are Mitsubishi and Daikin, but that is another price league, as well as chinese ones like Midea, Gree, Foxair, Sprsun, etc. They all have very high minimum outputs, like 4.5kW thermal for the 10kW model.

What is your opinion, which brand might be the best route to go on, assuming hydraulics, pipe sizes, weather curves are all set up well?

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As you can see from the heat pump on https://heatpumpmonitor.org, there is not one clear ‘best’ heat pump. The reality is that the design, installation and commissioning has a much greater effect on performance than choice of individual heat pumps.

That said; some heat pump have better control algorithms, which makes them perform well in a wide range of installations with minimal tweaking. Out of the list of heat pumps you mention, Vaillant is the best IMO.

There’s a lot of real-world data on Vaillant heat pumps on the Heat Pump Monitor database. They have very good modulation and cycling contgrol https://heatpumpmonitor.org/heatpump?filter=vaillant

The 7kW Vaillant can only output 6.7kW at -3C, therefore the 12kW module would probably by the best choice, unless you are confident that the construction is good and the heat loss is more like 5kW. Which I think it should be a for a new build of that size.

Local Home Assistant integration is possible using eBUS, there are some extensive threads on our forums about this.

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Love it​:rofl: -: ain’t that the truth

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Hi Glyn!

The smaller Vaillant is in the same situation as the Panasonic L-series 9kw. In cold winters, it may not provide enough heat for the house&dhw, given the calculations are too optimistic.

If my info is correct, the 105/6 series Vaillant is a software limited 12kW unit, with the same 5kW minimum modulation.

If we cannot reach the desired 2.5-3kW minimum output that the LG has, I’d rather choose the Panasonic M T-Cap 9kw that also has around 4.5-5kW minimum modulation, or the Midea Arctic Nature which is very cheap, cheaper than the Samsung, and has service staff in every town.

The real reason is that there are simply no “real” 9kw heat pumps available. They are either limited 12-16 machines, or 9kw nominal units that have 6-7kW power at - 15Celsius.

I am very keen on the new Mitsubishi dual compressor unit, but sadly it will not be available in my country until 2026Q4.

What do you think of the Samsung model with integrated pump? Isn’t it too loud for 8kw in this small chassis?

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If you talk to Mario Dodic, he has good things to say about Panasonic and Bosch in EU - pretty sure he was OEM side support for Panasonic for a while so may have insights on their low ambient performance for you.

I thought Vaillant was a German company but interesting to read that they are not so present in the German forums. Viel gluck!

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I reckon the Grant HP290 9kW is a real 9kW heat pump, I’ve installed one in my house. Under worse conditions it can hit 8.5kW, and it can modulate down as low as 2.5kW (300W electrical), see the HPM database for real-world test data: https://heatpumpmonitor.org/heatpump/view?id=33

Samsung make decent heat pumps, but the controls are poor.

Agree, Panasonic heat pumps look rather good. The data on HPM is positive. I’ve also heard good things about Bosch, but they are not so popular in the UK.

But, as I mentioned, the system design, install and commissioning is more important than a specific make or model. Are you self-installing, or do you have an installer? If using an installer, it’s usually best to go with what they recommend and are familiar installing.

What’s the design for your system? I.e Design flow temperature? Control strategy? etc.

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I am the installer myself. I have the local certifications and licenses to install most manufacturers sold here.

Previously, we mostly used the classic 4-port parralel buffer setup for customers, as that is what most manufacturers accept as a warranty condition. It proved to be just good enough. It keeps the house warm, but nothing more.

For our own house, I’d like to think just a little bit out of the box. Not much, just a little.

We’d install a 2-port parralel buffer setup with a 100L Stainless buffer. There will be 2 pumps(Wilo Stratos Pico), one for screed underfloor heating circuit, one for concrete embedded ceiling cooling and heating. No mixers are included. I will balance the flowrates using the Wilo control screen to match with the heatpump’s primary flow.

There is no zoning except for temperature limitation in bedrooms, and for shutting off cooling in bathrooms. Every room has RH and T sensors installed.

The water circuit is quite well thought out, as the slab and ceiling, I just need a good heat pump selection with wide modulation and good cold performance. Preferably without compressor / fan control quirks, which seem to be nonexistent.

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That sounds fantastic. What your design flow temperature for -15C? It’s quite rare in the UK to get less than -4C, we usually design for around -2C/-3C, but most of our houses are poorly built.

I installed a Samsung heat pump in my old house, it did perform very well, but I had to do quite a bit of tweaking of the controls to make it work well. The good thing about Samsung is it’s relatively easy to integrate with home automation platforms, it had documented modbus. There are several heat pump optimisers e.g Homely, Havenwise, Passivuk that will automatically optimise the heat pump which resolves the issues with poor controls.

No heat pump is perfect. Viessmann Vitocal or Vaillant Arotherm are two of the best IMO. But any heat pump can work well if it’s setup and installed correctly.

Will you be fitting monitoring? I would love to see some real word data of a heat pump working at -15C

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The Design flow temperature is 35-36°C. This is enough for the house when both the screed and the ceiling radiant heating is working. Approx. 38-39°C is needed when only the underfloor screed is in use.

I plan on using my Home Assistant system for monitoring, If I can get a good deal on a decent DN25 ultrasonic heat meter, I might install one as well. OEM would be great too, if it can run on open-source hardware, but soucing an emonPi kit from the UK is not viable for me.

Home Assistant integration is mandatory, as the Temp/humidity sensors are integrated in that system, too. I want to set the cooling water flow temperature according to the worst measured dew point among the rooms, maximizing the cooling effect.

As I wrote, it is almost a year old topic for me. Panasonic has the best integration, but lacks proper 9kW class machine. LG is the second with modbus, albeit it has some inverter control anomalies.

Panasonic rolls out a new 9kw R290 model this year, if I can get one, maybe it will be the right choice.

The available Panasonic T-CAP models are made to have constant power down to -15, but 4,5-5kw minimum power output is the price for that oversized compressor.