Posted by: @derek-m

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Who is the manufacturer?

Mitsubishi

I observe that under Mitsubishi auto adaption that set back to 15C at night causes the HP to cease heating and runs in freeze stat until the next set point at 0600. When it was seriously cold recently, in the minus 10C area over night, it was waking up around 0500 hours to commence its days work regardless that the wireless room stat was not calling for heat.

Unfortunately MCS does not always mean a good installation.

Posted by: @abernyte

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Posted by: @derek-m

↑

Who is the manufacturer?

Mitsubishi

I observe that under Mitsubishi auto adaption that set back to 15C at night causes the HP to cease heating and runs in freeze stat until the next set point at 0600. When it was seriously cold recently, in the minus 10C area over night, it was waking up around 0500 hours to commence its days work regardless that the wireless room stat was not calling for heat.

It would appear that auto adaptation was actually 'adapting' to the adverse weather condition. 😎 Well done Mitsubishi. 😀 

Would you care to name your installer?

I would readily but the guy is seriously ill at present, hence the manufacturer service contract.

In reality, without monitoring equipment installed, it is very difficult to determine the actual, accurate performance of any heating system regardless of technology. Here is a link to a Linked in post, of a heating consultant finding out that his gas boiler is only 67% efficient after putting monitoring equipment on.

LINKEDIN.COM "https://www.linkedin.com/feed/update/urn:li:activity:7019635213781585920?updateEntityUrn=urn:li:fs_feedUpdate:(V2,urn:li:activity:7019635213781585920)"

***friday fun*** | Steffan Cook

***friday fun***
The answer is 67%, but what is the question?
EDIT: following more analysis → updated to 75%

Read More

The question is "What is my boiler efficiency in heating my house?"

Since Marko Cosic gave me a heat meter I can now calculate this. And..... 67% is actually dissapointing. I was hoping for higher, given that I run my boiler at a low flow temp (40C return) to maximise condensation return and that the "test result" efficiency for this boiler in the UK Product Characteristic Database is 88% efficient over the Winter. [See entry for (i-mini 30KW combi)].

It would only take a small nudge in prices to make running a heat pump worth it (still have to worry about the greater depreciation cost of a heat pump and the real 'marginal' grid carbon emissions involved in its use though). Sadly there is no certainty in prices of energy right now so I can't make that calculation.

Also a home combined heat and power unit (micro-CHP) would run at the same 70% efficiency roughly on gas but would make electricity for me also which might make me a net saving for me. It would need to be a very small unit though.

#energy #electricity #homeheating #gasnatural #energyefficiency #energycrisis #energyanalysis #gasboiler #heatpump #microchp

Marko Cosic Nathan Gambling Steven Ashurst Veritherm UK Luke Smith

**note**
I was going to make allowances for cooking gas (maybe 2-3KWh per day) and also hot water (<11KWh per day) - I even prepared special data for this, however in the end decided it was unnecessary. The line used to fit the data shown is strongest at the high end of gas usage where these additional demands are only a small % contribution to the much larger demand from space heating. This shows that space heating dominates this trend in the graph.

Of course the 'efficiency' calculation is more complex than this simple graph, but for a headline gas to heat conversion value a range between 65-70% would seem fair. | 27 comments on LinkedIn

As a rule of thumb, if the heat pump system has a buffer tank, system separation, if you can see more than 1 pump, and there are third party thermostats, there is little chance that there will be any level of reasonable performance and there is a good possibility that the bills will be very high.

@editor they can but if you go ahead and purchase based on the information supplied then it must be accurate and honest otherwise you probably have a claim

@sapper117, I guess it comes down to people and their ‘experience’. We purchased our property from people that were used to buying and selling properties that they fixed up and sold, and they were less than truthful in their signed documents and forms.

When we raised this with our solicitor post purchase (having discovered the issues after moving in), the legal fees and claims process was very costly and not worth the financial effort.

I suspect it might be the same with a bodged heat pump. If you have the capital, it might be cheaper to fix and replace then to seek legal routes to get financial compensation. 

@editor I suspect you are right in England - up north we have to sign docs with legal answers and each sale has a week to check elec gas boilers etc which if the buyer is well briefed and carried out their due diligence then they will have an engineer in on day one. As a retired property manager I would organise this for clients buying a new property ( new to them) and never had a problem here.

If I were buying a place with tech I wasn't familiar with, I'd probably look for an expert to do an inspection.  Surveyors are common for structural issues, electricians for electrical checks, boiler people for gas heating and I don't think heatpumps are much different. So I might pay somebody to visit and inspect - if I didn't know anyone, likely finding somebody who is certified by the manufacturer of this particular model to check it's installed correctly.

In this instance I probably wouldn't trust a 'gas safety certificate' or its heatpump equivalent (proof that it's been serviced recently) since we don't know if the person who recently serviced it knew what they were doing, unlike gas safety certs which are well understood.  Evidence of servicing is good, like GasSafe or HETAS paperwork is - although heatpumps don't really need a lot of servicing so it wouldn't be a showstopper if it didn't exist.

If I were being picky I might also ask my inspector to do heatloss calcs and confirm the unit is correctly sized.  It might be too large if additional insulation was added after it was installed.

Although I might be tempted to make sure there's some slack in the budget just in case it did need to be replaced - which should be cheaper than a full install since it's mainly the outdoor unit that would be changed.

@prunus the odds are the heat pump unit would be ok its the installation and heat calcs you would need checked as it seems that most of the problems emulate from failing here - and costs to make good could be larger than a new pump