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Posted by: @scalextrixit's a question of the right tool for the right job.
Bog standard house (for it's era) with a few well documented changes = the standard heat loss measurement should be fine. The Elmhurst training does talk about alternatives for more complex scenarios
In a way, @scalextrix, you and @jamespa are talking about different points.
You’re quite right that one needs the right tool for the job. However, even the right tool needs to be used correctly.
Is there anything inherently wrong with the maths behind the heat loss survey process? Not as far as I’m aware. That means it could be one right tool for the job.
Is the heat loss survey “tool” used properly? De facto evidence is “no”; countless customers finding after the fact that their home was given a significantly pessimistic estimate demonstrates this.
How is the tool being used incorrectly? There are two gotchas. Firstly, surveyors make assumptions that have a large material effect on the outcome. That doesn’t mean the model is bad; merely that it can’t work with bad data. Secondly, the outcome - the estimated heat loss - isn’t routinely tested against the real world. Sometimes assumptions have to be made but that’s why you test where you can, and the industry standard is not to verify.
So your assertion is that the heat loss survey is a reasonable model. I agree.
@jamespa’s assertion is that the heat loss survey isn’t used properly. I agree.
It’s not the model that’s flawed; it’s the implementation. And until the survey process includes a bit that says to the surveyor “now cross-check your estimate”, it will remain flawed.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
This discussion has gone quite deep for our Hello & Welcome topic.
If you're new here, and still wondering whether to introduce yourself, then please do so.
There aren't that many problems we haven't been able to resolve one way or another
even if it's just a shoulder to cry on.
Save energy... recycle electrons!
Hello @paultheheating - I'm a rural Moderator!
What's the heating problem?
In your house or a tenant's?
(We understand that diagnosing issues in a house lived in by a tenant is more difficult as you may not have open access.)
Save energy... recycle electrons!
Hi. Just joined. I found the site by accident, after searching for any information on Daikin Altherma 3 sensors.
I've had my Daikin ELDA11D3V3 since the beginning of Dec 2025, and am looking to maximise the COP / minimise electricity use. I have solar panels & a 10kWh battery that help me avoid the more expensive rates without needing to go cold.
Welcome in, @velcro. I'd say you've come to the right place; there's a lot of stuff written by quite a few members about tweaking Daikins so have a bit of a search on existing topics and shout with any questions when you're ready.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
@velcro welcome to the forums. Please feel free start a dedicated thread where you an get advice for your system.
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Hello all - just joined! Found the RHH as partner and I have just moved into a new build in rural Fife with an Ecodan heat pump and I'm having all sorts of heating problems! Genuinely feel quite miserable about it.Insane consumption and delivered stats, but low temp in upstairs rads. Installer hasn't bothered walking us through the controls yet and, in this very cold snap, I'm having to try and make sense of it myself. Very keen to understand how to bring down consumption and delivered stats (while maintaining good COP), and genuinely get the most out the Ecodan.
Welcome to the forum, @green_fox; glad to have you on board.
You've got a very common heat pump (in fact, I've got an Ecodan as well) which is generally very reliable and good quality. However, the journey towards getting the best out of it will involve a wee bit of back and forth as we get further details from you and you try out a few of the suggestions members here make. As a result, it would be great if you can create a new topic specifically for discussing your heat pump and issues and we can keep everything together.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
Thanks @majordennisbloodnok! Good to be onboard and thanks for the warm welcome. I'm drafting some information now, so will post a thread later today after work. Would you advise posting a new topic under the ASHP-specific forum? As I say, very new to this world and so may need some acronyms and details explained!
Not a problem, @green_fox.
Yes, the topic would sit well under the ASHP-specific forum, but don't get too hung up on getting things perfect here. We're a pretty easy-going bunch so won't be crawling over your back if you post something in a less than ideal place.
As for the jargon, we've a useful thread for you. https://renewableheatinghub.co.uk/forums/rules-terms-of-use/renewables-glossary/
Hopefully that should help you cut through some of the recurring acronyms, but if there's anything you don't understand then just ask; we've all been on the same learning curve you're on at the moment so are happy to explain in approachable terms.
105 m2 bungalow in South East England
Mitsubishi Ecodan 8.5 kW air source heat pump
18 x 360W solar panels
1 x 6 kW GroWatt battery and SPH5000 inverter
1 x Myenergi Zappi
1 x VW ID3
Raised beds for home-grown veg and chickens for eggs
"Semper in excretia; sumus solum profundum variat"
If you are new to heat pumps can I suggest you read this introduction. You need to forget almost everything you thought you knew about running a boiler (much of which was poor economy, and poorer comfort, for boilers as it happens, but nobody cared because North Sea gas was dirt cheap).
As @majordennisbloodnok says we are (I hope) a very forgiving bunch here, just tell us about your house and system and you will get plenty of help. Please rest assured that, properly set up and operated, heat pumps can be brilliant and deliver far superior comfort for similar running cost to a gas boiler. Also please rest assured that your electricity consumption at present is not typical, these are probably the coldest days of the year and that does push consumption up a lot.
4kW peak of solar PV since 2011; EV and a 1930s house which has been partially renovated to improve its efficiency. 7kW Vaillant heat pump.
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