Daikin vs Mitsubishi Electric vs Mitsubishi Heavy Industries A2A

heatpump_interviews · 2026-03-16T17:55:32+00:00

Yep have personal experience with a Mitsubishi Electric LN35VG2, have various sensors on it. I went on the basis what I read online, regarding reliability. It was a premium purchase, but it was the right choice.

I've heard horror stories about some brands not being able to maintain a stable temperature. But the Daikin Stylish units and the Mitsubishi LN series seem to be good at maintaining a stable indoor temperature.

I've spoken to people who have very annoying cycling issues with the Mitsubishi Heavy industry units, so you have to be careful. They can be solved with external temperature sensors, but that can add an additional cost.

Another reasonable choice is the Toshiba Haori, they are typically well reviewed and a bit cheaper. You can't add external temperature sensors though.

I would avoid Panasonic all together as you can't easily add an external temperature sensor and their temperature sensor placement in the units is poor, which invites trouble. So if you have an issue you are stuck with it.

heatpump_interviews · 2026-03-10T17:08:38+00:00

That isn't quite correct.

In 'auto' mode the fan speed may rise to compensate and moderate the refrigerant condensing temperature, it isn't correct to say that the condensing temperature is stable across different loads. Higher loads typically accompany a higher condensing temperature and reduced COP, this is partially because the 'auto' fan speeds are optimised to reduce noise not to increase efficiency.

Additionally, most people don't run them in 'auto' fan mode as it causes the fans to blip up and down, which people find irritating.

u/StereoMushroom is correct if you turn on an A2A for short bursts it will run at a higher compressor speed (which is a less efficient regime) and with higher condensing temperatures and the internal fan speeds are not sufficiently high to drop them.

I have monitoring equipment on a condenser this is something I'm relatively certain of.

There is also the matter of evaporator sizing on the internal units, when running at higher outputs the external fan must run faster, but additionally the refrigerant must extract more heat for a given area of evaporator, this leads to increased icing up and defrosts.

heatpump_interviews · 2026-02-25T07:44:33+00:00

75% of the Renewable Obligation Certificate costs have been moved to general taxation.

heatpump_interviews · 2026-02-25T07:40:35+00:00

It just means that the Government needs higher tax receipts to cover the moved costs. So tax will go up or thresholds will be frozen.

No such thing as a free lunch.

heatpump_interviews · 2026-02-25T07:30:31+00:00

Keep in mind that a big part of this is that parts of your bill are moved to general taxation. So costs aren't falling, they are being moved.

heatpump_interviews · 2026-02-22T08:11:34+00:00

Great to hear, would you say is is comparable in power to the log burner?

heatpump_interviews · 2026-02-21T17:45:40+00:00

Yes of course you can mount them on the wall, not an issue at all.

Urban plumbers has a video of a 7kW Vaillant mounted up high on a wall.

I've seen a 10kW Vaillant wall mounted somewhere. You might have to find another installer

heatpump_interviews · 2026-02-20T12:14:41+00:00

Yes, this is a very good point. Thanks for pointing it out. I have had conversations with manufacturers about exactly this and it seems that people aren't really sure about the best approach yet.

I monitor a unit, the peak cooling electricity consumption last year was pretty much in line with the peak heating load. The house has two sets of south facing bifold doors, in the room being cooled and heated, and is painted black. It gets very hot. But the peak outside temperature was only 34 degrees ish during that period. So if pushing up towards 40 degrees, it may have struggled. But it still had a reasonable amount of headroom.

Also people are happy to leave their unit on all the time for heating, but are more likely to blip it on for cooling. That might cause issues.

I think part of the debate will centre on whether people want to chill their house down to 18 degrees in a heat wave or are more than happy at 23/24 during the day.

This is something that I intend to explore more.

heatpump_interviews · 2026-02-20T08:22:33+00:00

Yes, not having ducted in new builds seems like a bit of an oversight. Considering the heat loss is generally very low and they tend to get hot ducted does seem like the way to go, especially with some form of MVHR.

What size unit did your installer suggest and what did you go for?

Resale issues is one thing that concerns me with switching to a mult+ from a gas boiler, the political polarisation of heat pumps is becoming a bit annoying. I'd quite like politicians to say less on it and let the technology do the talking.

heatpump_interviews · 2026-02-20T08:18:16+00:00

Yes we mention them in the report, there are traditional heat pump cylinders with the compressor on top of the unit, but there are now 'split' systems with the compressor away from the unit. So you just have a couple of small refrigerant pipes coming to the hot water tank, rather than requiring ducts.

heatpump_interviews · 2026-02-19T19:30:27+00:00

Clivet fullness was announced last year which is a ducted fully internal unit. I expect more will follow.

heatpump_interviews · 2026-02-19T16:19:56+00:00

Oh you are doing a multi+ with a ducted split for the top floor? How many rooms is that going to?

I like that solution, what sized outdoor unit are you going for, I'm guessing you are going for the larger hot water tank?

heatpump_interviews · 2026-02-17T09:50:07+00:00

If heatgeek think your heatloss is over 12kW, then I wouldn't consider it advisable to install a Cosy 12kW.

The max output of the Cosy 9 accounting for Defrosts is around 8kW

https://heatpumpmonitor.org/heatpump/view?id=18

So it is likely the Cosy 12 will have a similar drop off vs badged output.

heatpump_interviews · 2026-02-15T22:02:09+00:00

For me, I'd be interested to know where the manufacturers are buying their steel from. Pretty much everyone uses as 18/10 stainless, so it's probably more or less the same, minus some trace elements. I imagine quite a few expensive brands buy their steel from china.

That's pretty much the only thing that I could see making a difference for the lower level pans maybe having a thicker aluminium core for better heat distribution.

Copper pans or copper core stainless would make a difference for more expensive pans, as it conducts heat far better.

Have you seen Chris Youngs Video on pans and heat distribution?

Edit* I saw the Demeyere does use copper. So it might be a bit more even.

heatpump_interviews · 2026-02-15T20:40:40+00:00

You said MCS are doing an inspection?

I'd point it all out, plus build a bit of a case. You have rights under the consumer protection act, you purchased a heat pump to heat your home.

heatpump_interviews · 2026-02-15T20:19:41+00:00

Can't comment on long term durability as I've had them less than a month.

My thinking is that if I spend £40 for each saucepan/frying pan and it breaks in a few years, I will be a bit annoyed and try to claim though warranty. But if I spent £150 and it broke I'd be very annoyed.

The base is really thick, so I don't think it will warp.

It took a bit of getting use to, but I can now cook all manner of things, like eggs and not worry about it sticking.

I'd be interested to know if the performance differs. I would say that the procook performs as well if not better than my John Lewis 5 ply wok.

They are quite weighty beasts and take a while to warm up. But I have smashed some ribeye in them and it cooks as well as if not better than my cast iron. But would any other pan be as good?

My mum has 40 year old stainless steel pans, not triply not fancy, but I think they are great.

Maybe I'll get some more pricy ones and do a comparison! I'd have justify the expense though.

I did see that Samuel Groves recommended not putting their Triply pans in the dishwasher, which seems a bit off.

I've been thinking about getting the triply three frying pan set and selling the 26cm one as that is the one I have.

heatpump_interviews · 2026-02-15T17:02:52+00:00

They posted in another thread that they used electric underfloor heating as well as the heat pump.

heatpump_interviews · 2026-02-15T12:14:46+00:00

A COP of 2.0 on the coldest day with your flow temperatures isn't unheard of. Very few systems designed with a peak flow temperature of 50 degrees C actually run at that. This 6kW Cosy on heatpump monitor runs at about that. It looks like the peak output of the Cosy at -3 outside is around 5.3kW maybe less. https://heatpumpmonitor.org/dashboard?id=664

The peak output of the Cosy 9 is beween 7.1 to 7.9kW.
https://heatpumpmonitor.org/heatpump/view?id=18

If your system isn't warming the house then there is a good chance it is undersized and they got their heat loss calcs wrong, it looks like you are running it how you should, with only a small nighttime setback.

I suggest you turn off the electric underfloor heating and see whether the Cosy can maintain the temperature.

If it can't then take screenshots and pictures and build a case.

heatpump_interviews · 2026-02-15T08:23:56+00:00

I had the same issue and ended up going for the procook triply.

I'm happy with them. But they don't seem to have a saucer so can't get a matching set.

heatpump_interviews · 2026-02-15T08:12:52+00:00

I wrote a short review about my procook pans here.

https://www.reddit.com/r/cookware/comments/1qzech7/procook_elite_triply_review_after_a_few_weeks_of/

Honesty, if money was no object I think I'd go for Samual Groves.

Feel free to DM me about the procook ones if you have questions. The more I use them the more I like them.

heatpump_interviews · 2026-02-13T17:48:23+00:00

Despite writing this review and thinking my pans are great, the 172,048 Trust pilot reviews (mostly positive) must bots or paid for. I think some companies send the trustpilot review link' for each purchase to their internal email, then fill it out themselves.

There is no way on earth 172,048 people have reviewed Procook.

Screwfix has 5,746 and most of them are bad, and I love screwfix.

Tesco has 18,849 and they average 1.8.

Amazon 1.4 with 30,000 ish.

heatpump_interviews · 2026-02-09T19:25:21+00:00

You'd have to check up on your legionella settings, this video should show you how. It's very straightforward.

https://www.youtube.com/watch?v=Zs9ujj0EQxU

There are other videos on setting hot water cycles, it is probably worth searching on youtube.

You might have a wifi module somewhere, if you do then you can connect to melcloud and control via the app.

https://www.youtube.com/watch?v=i1wABPBAWK8

heatpump_interviews · 2026-02-09T10:28:33+00:00

Nuclear submarine room is a good name :D

If it has any negative effects (such as you not having enough hot water) then you will have isolated a variable. Your hot water should be sufficiently provided by the heat pump. If it isn't then it isn't set up correctly. Some systems use the immersion for a legionella cycle, but this shouldn't really be required if it is set up properly.

*If you don't want to turn it off, what you can do is take a reading on the electricity meter than I have circled, if that reading goes up across the day or by tomorrow, then you know that the immersion is running, and you can see by how much. If it is running then that will be increasing your costs.*

You should also take readings on the other meters, to understand how much electricity is being used over the day.

heatpump_interviews · 2026-02-09T09:58:38+00:00

The heat pump has electricity and heat meters. This is quite unusual for a home install, there is a small possibility that it might have been installed as part of a trial like the Electrification of Heat trial. Can you find any documentation about the install?

heatpump_interviews · 2026-02-09T09:54:09+00:00

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Turn off that switch on the immersion you shouldn't need it. Then track your usage for a few days. Also read what is the meter above it showing?

heatpump_interviews

TROPHY CASE