@editor interesting re energy assessments. i also had three two were about the same one was almost double the other two. the highest used an intelligent automated app.!!!!!! it measured room sizes but other two used separate measures and inputted results as they progressed. But one point the most accurate said was they take into account the direction a room faces. if the room gets little or no sun it will they said need more heat. seems to make sense. i had two rooms that had that issues and they doubled radiator capacity putting doubles in place of singles. hope i am not confusing issue but thought worth a mention

Posted by: @keithb

↑

@editor interesting re energy assessments. i also had three two were about the same one was almost double the other two. the highest used an intelligent automated app.!!!!!! it measured room sizes but other two used separate measures and inputted results as they progressed. But one point the most accurate said was they take into account the direction a room faces. if the room gets little or no sun it will they said need more heat. seems to make sense. i had two rooms that had that issues and they doubled radiator capacity putting doubles in place of singles. hope i am not confusing issue but thought worth a mention

Loss assessments can be a very serious case of GIGO.  I had two, both coming out at 16kW following, in each case, a 3 hour survey.  I did the calculation myself and got to 10.5kW.  The measured loss is 7kW.  I can account for all the differences and sized my heat pump for 7kW, which turned out to be the right decision.  

The new rules introduced from about June last year are supposed to improve the situation, especially the significant overestimation of air changes.  As to whether they have, only time will tell!  Personally I would always recommend a sanity check against gas consumption or floor area/construction if at all possible, unless the estimated loss is 5kW or less, in which case it wont make any difference because you are fitting a 5-6kW heat pump whatever the actual loss is, because (with the exception of a couple of rarely used outliers) that's whats available!

I had a Worcester Bosch compress 2000 fitted March 2026 by Project Heating Solutions,The install seemed to go well and tidy work. The problem I had was after turning on the Heat Pump they just and bleeding all new radiators they left. The only person left was the electrician. One of the radiators wasn’t even turned on. I was not told anything about the system and when I asked they said just leave it. 
After a few days I noticed using a lot of electric and noticed the flow temp never changed from 50degrees even on warm day as I thought it should if weather comp was set. Asked the question and they said yes it was and to leave it. One week later I decided to find out myself. There was no weather comp set, just set at 50 degrees. I searched the website and found out how to set myself. Spoke to the company and explain all this and ask for someone to come out and balance my radiators ( I knew they hadn’t) and explain the system. They came out turned a few radiators up and down, didn’t have a clue about balancing and told me to use the stats on the radiators even though I got told not to use them. Then heard the guy on the phone asking how to set a weather temp. Asked them to leave because they didn’t know what they were doing. Before they left stuck a sticker near my control panel basically saying do not touch. 
Now waiting for a head engineer to come out in May.

@josejo Reports of such lack of commissioning and downright ignorance demonstrated by the installers gives the whole idea of using heat pumps a VERY BAD NAME! When we have such bodies (like them or loathe them) as MCS, none of this should be happening - ever! Please pursue your convictions on this - you will find plenty of advice on RHH to get you set up. I have made a contribution or two so if you wish to balance your radiators to your own satisfaction, just toodle along to:

https://renewableheatinghub.co.uk/how-to-balance-radiators-the-role-of-the-lockshield-valve

As to Weather Compensation, yes, almost every system should be set to this and will provide greater comfort, consistency and economy too. Feel free to ask as you progress, there are a great number of people on the RHH forum eager to help. Regards, Toodles.

Ah the gift that keeps on giving! Finally getting around to refurbing the spare room, this is where the installers had to hack the floor apart to fix a leak because they didn’t pressure test the system before turning the water on for the second time, the first time they turned the water on they realised they hadn’t attached one of the rads so I had mains pressure water flooding my lounge! Anyhoo took up the old flooring and revealed what I can only describe as a masterclass in plumbing and electrical safety! This was installed Jan last year and that is the feed to the immersion!

@josej, this is exactly where the industry keeps tripping over itself, and it’s not the hardware, it’s so often the handover and commissioning.

You can have a perfectly decent unit like the Worcester Bosch Compress 2000, installed neatly and still end up with a poor outcome if it’s effectively left in “default mode” and nobody takes ownership of setting it up properly.

Running fixed at 50C with no weather compensation isn’t just a minor oversight… it’s inexcusable. That should never be left for a homeowner to discover and correct themselves.

But I’d take it a step further briefly… this isn’t just about a bad visit or a couple of engineers not knowing what they’re doing. It’s a structural issue. We’ve got installers treating commissioning as a quick final step, when in reality it’s where most of the performance is won or lost.

Balancing, setting the curve, checking flow rates, explaining controls… that’s definitely not optional, that is the job.

The fact they told you to “just leave it”, then came back and clearly didn’t understand balancing or weather comp, tells you everything about where the gaps are.

The positive here is you spotted it early and started digging… most homeowners wouldn’t and would just sit there with high bills and assume that’s normal.

When the head engineer comes out, I’d be VERY direct. Ask them to walk you through:

• how the weather compensation curve is set and why
• what flow temps they expect across the season
• how the system has been balanced (properly, not just “turned a few rads”)
• and what your expected electrical consumption should roughly look like

If they can’t clearly explain that, you’ve still got a problem.

You’ve done the right thing pushing back. Don’t let them close this out until it’s actually working as it should.

@josejo 

If it's not too late withold payment and any sign off for the bus grant until this is fixed.  The only thing that motivates installers that are sloppy like this is money!

@jamespa unfortunately paid, kicking myself but at the time I didn’t have a clue how it worked. Wish I’d done my research first. But I won’t let it drop until I’m happy

@editor I have a list to ask, hopefully he know what he’s doing.

@josejo that's good to hear and stand your ground!

@editor climate setting? I had same issues many had but these articles and feedback are invaluable. I must go back to bosch sounds silly but the manual is thick and not always easy to follow. I had the electrical wiring issues, leaks etc even rust in the main feed. I think they forgot to add inhibitor. When i complained i had to pay to have the system flushed to get out rust and bits that had built up after just 10 months. They added fernox f1 but i roughly did my own calculation on water capacity and bought a test kit and concluded that with the two or three larger rads plus the 28mm new pipe runs i probably needed more inhibitor. The test suggested it was weak so i added more myself. The test kit now says the solution is strong so hoping that has stopped any more rust issues. I have a bosch compress2000 but my electricity bills in jan and feb were over £500 each month. I have solar and batteries but lets face it they dont contribute much to the running of the heat pump in winter. So very unhappy but yo get help not easy. Bosch techies on the phone are good but i agree if the system is not comprehensively explained on install its a nightmare. Sounds silly but i was talked through setting the temps etc in the climate control by Bosch but stupid me i cant work out how to turn it on. I feel bit of fool keep going back to bosch but think i must as i cannot afford another expensive set if winter bills. I have found my bill for electricity ( no gas now) is 30-40% higher than combined gas and electricity bills were. Several of my neighbours have upgraded boilers after they saw my experience with a heat pump. I can't afford to go back to the boiler so got to make this dreaded heat pimp work better. I tried to find a good techie i could ask to come and check it all but seem few and far between.

@keithb I actually found a video on YouTube to set weather compensation. Figures kinda made up so might be a case of playing with figures.