Mitsubishi vs Samsung Heat pump

[Slippin Jimmy]

Hi,

I've had numerous quotes for heat pumps. The majority went for a Mitsubishi Ecodan 6kw PUZ-WM60VAA(-BS) heat pump with a 200litre water cylinder for about £4,000 (After the government incentive). But we've just had a quote for a Samsung AE080RXYDEG/EU 8kw heat pump with a 210-liter water cylinder for around £1,500.

Just looking for any input to see why I shouldn't go for the cheaper quote for the Samsung? Or if there's a reason most companies choose to go for the Mitsubishi.

One must, is that it must be able to integrate with Home Assistant. I know Mitsubishi does with the MELCloud integration, but unsure about Samsung. I want to only have the heating on & heating the water tank when the car is on charge and activated my cheaper Octopus Intelligent tariff.

I live in the UK, we have a small semi-detatched 3 bedroom new build house from 2019. I believe it's around 95 meters squared in total, and it doesn't need much heat to keep the house warm on the current gas boiler as it's well insulated.

 

Thanks.

[PhilT]

I have an Ecodan but as you are with Octopus, I would recommend you have a look at their latest heat pump offering "Cosy 6". If they can use your existing installation and tank it could be free with BUS.

[billt]

You can buy and add on for the Samsung (https://midsummerwholesale.co.uk/buy/samsung-heat-pumps/samsung-ehs-wifi-controller-kit-mim-h04en ) which uses a SmartThings app. It interfaces with Alexa and Google Assistant apparently so should be able to talk to HA. It's a pretty simplistic app, but lets you turn it on or off and change the temperature in 1 degree C steps.

 

8kW sounds a little on the large size for a fairly small well insulated house. I have an 8kW Samsung and it just about copes with about 170 square meters of heated space but mediocre insulation. It's slightly undersized but has been performing OK so far.

 

If I knew then what I know now i wouldn't use an R32 ASHP but an R290 want, specifically the Vaillant Arotherm plus. They perform much better at less than 5C outside temperature than R32 heat pumps. The 5kW Arotherm shoulc be more than enough for your house, but you need to get the heat loss assessed properly.

[joth]

Fwiw the HA MELcloud integration isn't really up to what you are after. It can't turn off heating or DHW (nor switch to cooling mode). It can request DHW boost, and adjust the room target temperature, which maybe enough.

Also, MELcloud itself is pretty flaky only update the device every 15mins, and I found hitting it with a lot of config changes confused it a lot. YMMV 

 

As an aside, the policy you mention sounds very limiting. Like, if the car ever goes on a trip away overnight or is in the garage being serviced anyone left at home in the house gets no heating or hot water. Obviously you can turn off automations then but it sounds a hassle. In my mind you want to boost usage during cheap rate but still leave things ticking over even when the car is not charging. The HA integration maybe just enough for that. 

[JohnMo]

20 minutes ago, billt said:

 

If I knew then what I know now i wouldn't use an R32 ASHP but an R290 want, specifically the Vaillant Arotherm plus. They perform much better at less than 5C outside temperature than R32 heat pumps

Just looked at the specs for the Arotherm Plus, and it has a SCoP of 4.48 at 35 degrees, compared to my R32 ASHP its SCoP is 4.46. So overall nothing worth writing home about. It may produce better temperatures, but mine never needs to go above 55 degs anyway, so zero advantage to me. Horses for courses.

[nod]

All the quotes we have had have been Ecodan 

For what it’s worth our neighbors have had a Samsung unit since 2008 With any issues 

[billt]

38 minutes ago, JohnMo said:

Just looked at the specs for the Arotherm Plus, and it has a SCoP of 4.48 at 35 degrees, compared to my R32 ASHP its SCoP is 4.46. So overall nothing worth writing home about. It may produce better temperatures, but mine never needs to go above 55 degs anyway, so zero advantage to me. Horses for courses.

 

CoP at 35 LWT 2C outside Arotherm plus 7kW 4.3 - Samsung 8kW 2.98 (Samsung 31% worse)

at -2C outside Arotherm 3.8 - samsung 2.67 (Samsung 30% worse)

 

At 7C outside Arotherm 4.9 - Samsung 4.71 so not much difference.

 

At 16:00 today the outside temp here dropped below 4C, eventually to 1.5C. The CoP over that period was 2.9. The previous day it was 4.8. That's a significant performance drop off. We've had quite a few days so far this winter with temperatures below 5C and virtually 100% RH, the combination of poor low temp performance and frequent defrosts is pretty dramatic at the times when you need heating most.

[JohnMo]

Really just says the Samsung one you are comparing against is not that good (old design). The Vaillant one is slightly better than my R32 one at -2, mine is still at 3.22 (15% worse).  Over the heating season, the number of days below zero are few compared to those above. Day to day or instantaneous CoP isn't that important, overall SCoP is. Then there is cost, the Arotherm Plus cost 3x more than mine and twice the Samsung one I expect, so a long pay back period.

 

Bigger impact on CoP and SCoP is design and installation. That can make manufacturer numbers meaningless.

 

[ReedRichards]

2 hours ago, PhilT said:

I have an Ecodan but as you are with Octopus, I would recommend you have a look at their latest heat pump offering "Cosy 6". If they can use your existing installation and tank it could be free with BUS.

 I read elsewhere that octopus will not quote for a LWT lower than 50 C.  This could adversely affect your running costs if your house can do better.    

[Slippin Jimmy]

I'll be running the heat pump only when it's on the cheaper rate, which is 7.5p kw/h, so a slight reduction in COP isn't a huge biggie. Just wondering if the Mitsubishi is worth the extra 2.5k or not, or if the Samsung will be easier to control via home assistant.

[billt]

10 hours ago, JohnMo said:

Over the heating season, the number of days below zero are few compared to those above. Day to day or instantaneous CoP isn't that important, overall SCoP is. Then there is cost, the Arotherm Plus cost 3x more than mine and twice the Samsung one I expect, so a long pay back period.

 

Bigger impact on CoP and SCoP is design and installation. That can make manufacturer numbers meaningless.

 

It's the number of days below 5C that matters and here we get about 50 of those a year, about 25% of the heating season. That's going to significantly affect the SCoP. And of course manufacturers figures for SCoP are about as useful as MPG figures. The number of variables in any particular installation is huge meaning that the variables used in the makers calculations are highly unlikely to be reproduced in any given system.

 

In my case I don't think that the installation can be improved in any meaningful way. It's designed with a flow temperature of 35C at OAT of -3C, it's completely open loop with a large water content, no buffer and uses WC with room temperature add on.

[billt]

If there is a Mitsubishi integration I would expect that to be easier to set up than Samsung.

 

Apparently there is a SmartThings add on which has been made to work with Samsung heat pumps. As it's Home Assistant I guess it won't be easy. In my (small) experience anything out of the ordinary is a pain to set up.

[JohnMo]

37 minutes ago, Slippin Jimmy said:

I'll be running the heat pump only when it's on the cheaper rate, which is 7.5p kw/h, so a slight reduction in COP isn't a huge biggie. Just wondering if the Mitsubishi is worth the extra 2.5k or not, or if the Samsung will be easier to control via home assistant.

I have a 6kW heat pump that is run during the E7 mostly, for heating and hot water, split 6 hrs heating, 1 hr hot water.

 

I say mostly as below about 2 degs I cannot get the number of kWh out the heat pump to satisfy the house over a 24hr period; in a 6 hr period. At 2 degs, I need around 60kWh. So at 2 and below the heat pump runs outside the cheap hours.  It runs until it satisfies a thermostat in the hall, which is set to 20 degs (+/- 0.1 degs)

 

So it will be worth looking at your heat pump choice (size) based on how you intend to run. I did run it a fixed number of hours, which was fine for a few cold days, but then the floor runs out of energy and you need to fully recharge it, while having a cold house for 24 hrs (it was -7 outside).

[JohnMo]

You should be able to run any heat pump via HA, just need a Shelly relay across the heat pump start up contacts. Then set your control in HA to open/close the relay as you require. 

[PhilT]

15 hours ago, ReedRichards said:

 I read elsewhere that octopus will not quote for a LWT lower than 50 C.  This could adversely affect your running costs if your house can do better.    

According to the Octopus heat pump helpline there is no such restriction and the range 35-50 would be ideally suited to the new Cosy heat pump, though the key selling point remains the improved performance at higher temperatures, tech details of which have yet to be made public. Anyway as far as the OP is concerned I can speak very highly indeed of the Ecodan range, especially in full auto mode where I'm getting COP in line with what the databook tables quote - around 4.2 at 7degC, at 40deg flow temp.

[joth]

6 hours ago, Slippin Jimmy said:

I'll be running the heat pump only when it's on the cheaper rate, which is 7.5p kw/h, so a slight reduction in COP isn't a huge biggie. Just wondering if the Mitsubishi is worth the extra 2.5k or not, or if the Samsung will be easier to control via home assistant.

 

I already answered about the Home assisstant ->  ecodan integration but maybe wasn't clear as I just referred to MELcloud, which is the cloud portal for ecodan.

 

As @JohnMo suggests you can also ignore the premade HA integration and just use a relay to trigger the call for heat input. This is the main control I use (albeit I use Loxone rather than Home Assistant to control the relay).  I'd actually go down this route rather than the MELcloud integration for your needs.

 

 

[ian192744]

On 04/01/2024 at 20:30, Slippin Jimmy said:

Hi,

I've had numerous quotes for heat pumps. The majority went for a Mitsubishi Ecodan 6kw PUZ-WM60VAA(-BS) heat pump with a 200litre water cylinder for about £4,000 (After the government incentive). But we've just had a quote for a Samsung AE080RXYDEG/EU 8kw heat pump with a 210-liter water cylinder for around £1,500.

Just looking for any input to see why I shouldn't go for the cheaper quote for the Samsung? Or if there's a reason most companies choose to go for the Mitsubishi.

One must, is that it must be able to integrate with Home Assistant. I know Mitsubishi does with the MELCloud integration, but unsure about Samsung. I want to only have the heating on & heating the water tank when the car is on charge and activated my cheaper Octopus Intelligent tariff.

I live in the UK, we have a small semi-detatched 3 bedroom new build house from 2019. I believe it's around 95 meters squared in total, and it doesn't need much heat to keep the house warm on the current gas boiler as it's well insulated.

 

Thanks.

 

 answering the HA integration: best way to do it with samsung is to install the modbus module MIM-B19 into the outdoor unit. Then modbus to HA machine  (or modbus to an ESP, ESP to HA). I use this and it works well. My original intent was to use it for control and I do have the ability to do so, but I mainly use it for monitoring, I can see pretty much everything. for some idea what you can track: my system is https://heatpumpmonitor.org/system/view?id=45 on heatpumpmonitor.

COP's are ok 4 ish in milder weather, but drop noticeably below 3 once temp is below 3C or so.  Probably a newer on like the Vaillant would do better, if I was choosing again now that'd be on my shortlist.

 

I can get my samsung 16 down to 4kw but thats pushing the lower boundary. I have a 200m2 1973 house, my house needs 10kw when its -3C, 4kw when its 7C . so its ok.  but from what I've read on other fora, the 8 doesn't get down as well , can't do 25%, more like about 3.0 kw. If your house is 100m2 and well insulated 2019 new build then an 8kw samsung will be too big, its minimum of 3.0kw in mild weather will be way overpowered. make sure you research the minimum turn down of the options you are looking at. (most mfrs won't tell you, you need to glean from other users on fora).

 

Are you able to carefully measure your current gas boiler use to workout your heat throughput?

 

[Beelbeebub]

Also check the minimum power at your "maximum" outside temp. 

 

Being able to turn down to 2kw at - 7 is no use when you need to turn down to 2kw at 10C. 

[JohnnyC]

Hi there,

 

Just wondering what the OP finally did about this.

 

I am in a similar situation. My installer is pushing for a Mitsubishi Ecodan 8.5kW (R32). They say that it is more reliable than competitors (especially Vaillant). But I am tempted to ask them to install a Samsung Mono Gen7 8kW (R290) that should come at ~1£k cheaper overall.

 

Similar to the OP, HA integration would be useful.

 

I have checked in here (https://heatpumpmonitor.org/) and neither of these models rank very highly in terms of efficiency (no Samsung Gen 7 on the charts as far as I can tell, so looking at Gen 6).

 

Any reasons why I should pick one model over the other(s)?

 

Thanks very much in advance!

 

[JohnMo]

7 hours ago, JohnnyC said:

Any reasons why I should pick one model over the other(s)?

You really need to find the technical manuals for each model and do a little research. You need to understand turndown (min output) and your likely flow rates.

 

Most likely you will run Weather Compensation, so compare the headline SCoP for say 35 degs, for each model. And try to find out the min kW output, your normal running point 50% or less than the coldest day.

 

But more important than any of the above is system design, complex design with lots of zones, timers can lead to piss poor performance from the best heat pump.

 

Why do you need R290, because it can do 70 degrees? A good design should never flow above 55, even for DHW.

[sharpener]

IIRC @markocosic informed us that Samsung use hot gas bypass to achieve their (not very good) turndown figures and this nadgers the performance/efficiency. I wonder if this is true of the current model range?

[JamesPa]

1 hour ago, sharpener said:

IIRC @markocosic informed us that Samsung use hot gas bypass to achieve their (not very good) turndown figures and this nadgers the performance/efficiency. I wonder if this is true of the current model range?

The technical data book is here https://www.pasaz24cdn.pl/web5699/files/EHS Mono R290 [TDB].pdf

 

The refrigerant plumbing diagram does show hot gas bypass.

[JohnnyC]

3 hours ago, JohnMo said:

You really need to find the technical manuals for each model and do a little research. You need to understand turndown (min output) and your likely flow rates.

 

Most likely you will run Weather Compensation, so compare the headline SCoP for say 35 degs, for each model. And try to find out the min kW output, your normal running point 50% or less than the coldest day.

 

But more important than any of the above is system design, complex design with lots of zones, timers can lead to piss poor performance from the best heat pump.

 

Why do you need R290, because it can do 70 degrees? A good design should never flow above 55, even for DHW.

 

Thank you. I had not looked at turndown ratios, so it seems as if I have plenty of additional research to do.

 

I don't think I need R290, but I read in other posts people commenting that they would go for R290 if they would have to pick a heap pump again because of the better efficiency in cold weather (could this be one of the reasons why Vaillant installations top the charts in heatpumpmonitor.org?)

 

My SAP annual heating requirement is 15719.9 kWh. I won't need to heat up to 70C.

 

My setup is:

- UFH downstairs (~55 m^2) - still to be installed - it's an open plan, so I am aiming for 1 zone

- UFH upstairs (~50 m^2) - my builder installed 4 zones before asking me, but I plan to use these as 1 zone.

- 250L UVC

 

So I am hoping to have a flow of 35C for the UFH and 50 for the DHW?

 

I see that probably I should avoid the Samsung R290 because of the hot gas bypass if I am aiming to get higher efficiency.

 

Thanks again!

 

 

 

 

[JohnMo]

13 minutes ago, JohnnyC said:

people commenting that they would go for R290 if they would have to pick a heap pump again because of the better efficiency in cold weather

Again do your research, any heat pump (almost) will perform well if system design and operating philosophy is good. 

 

 

[billt]

17 hours ago, JohnnyC said:

I have checked in here (https://heatpumpmonitor.org/) and neither of these models rank very highly in terms of efficiency (no Samsung Gen 7 on the charts as far as I can tell, so looking at Gen 6).

 

Although the heatpumpmonitor data is interesting, I wouldn't attach much significance to the rankings. When you look at the detail differences between the installations you'll find that system design  is much more important than the heat pump model., as JohnMo said. There are also a lot of environmental and setup issues that change the rankings. A system in the south in a sheltered location is going to have a better CoP than a system in a colder and more exposed location, all other things being equal.

 

The best performing systems are designed to operate with very low flow temperatures, some of the systems have low room temperatures and low hot water temperatures (or no hot water heating from the heat pump), those will also improve the performance.

 

There are too few systems with too many variables to be able to come to any accurate conclusions.

 

You should also note that although the highest performing systems are dominated by Vaillant Arotherm+ (the most common heat pump in the list), a Samsung Gen 6 model is performing extremely well. The Gallt-y-foel, Gwynedd system has a Cop of 4.7 which is better than most Vaillant systems and not significantly worse than the best performing systems at a CoP of 5.1. You're well into diminishing returns territory here.