@editor

Posted by: @johnmo

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Posted by: @johnmo

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You can DIY an ASHP install for around £4k with a couple of new radiators, obviously more if changing them all and the plumbing.

 

 

I agree. There are several heat pump DIYers here on the forums who have done an outstanding job with their ASHP installations. It’s definitely doable for some, and they’ve saved quite a lot of money in the process and have very efficient systems. However, the reality is that many people simply don’t have the required skillset or the confidence to take on such a large project. Personally, I struggle to change a kitchen tap, let alone tackle plumbing an entire heating system. 

Precisely so. 

We need an industry that has the capacity and delivers a quality product at a reasonable price. 

DiY-ers complement the industry, they don't compete with it, because they are a tiny proportion of the total and can be a stimulant for demand.  Yet the industry seems to see them as a threat and seeks to exclude them through regulation which has the industry's name on.

@jamespa I agree with nearly everything you have said. However, today heating systems are critically undercharged for if you take inflation in to account. From research I have done, in 1980, a new heating system, full install was about £1900.00, a small car was about £900.00, today that small car is arround £20.000 +, therefor a new heating sysrem should be £40 000.00+. Cheap gas has pushed the income of heating engineers down to not much more than general labourers, a bricklayer can earn a lot more than a heating engineer, and we wonder why the work is so bad?

Most heat pump installers do not make money out of installing heat pumps, cotrary to what everybody says, there are a lot of hidden costs, they do it for the love of it and make their living out of installing gas boilers. You do not see many heat pump installers driving round in fancy cars, those that do, are not in buisness for long. Just look how many go bankrupt.

Posted by: @heacol

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Cheap gas has pushed the income of heating engineers down to not much more than general labourers, a bricklayer can earn a lot more than a heating engineer, and we wonder why the work is so bad?

Unfortunately I think this goes beyond heating engineers, its a facet of practical trades in our country - we value celebrity  and financial engineering more than the ability to do or design practical things.  This makes the 'trades' (and, arguably, engineering more generally) unattractive to most people with ability

Personally I think we might be better served by a higher skilled, higher paid practical sector.  Designing a cost effective high performance retrofit heating system is actually (so far as I can see as an individual with a degree in physics) an interesting problem solving exercise, where no two installations are the same, albeit that the actual plumbing is a bit back breaking.  This should be an attractive career for able people.  

Good people, I'm just asking this to make sure that I'm not fooling myself here:

if a radiator schedule identifies the output of a radiator 'at design temperature' as xyz, and the design temperature is 50º, it means the output of the radiator at Delta 50º? 

Be kind [insert Winnie the Pooh emoji] 😁🙈

@lucia have you had a booking date confirmed yet? Really keen to hear about your next phase.

@jamespa I agree wholehatedly.

@editor Yes, October 7th! 😁

Posted by: @lucia

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Good people, I'm just asking this to make sure that I'm not fooling myself here:

if a radiator schedule identifies the output of a radiator 'at design temperature' as xyz, and the design temperature is 50º, it means the output of the radiator at Delta 50º? 

Be kind [insert Winnie the Pooh emoji] 😁🙈

There is some possibility for confusion here. 

If its the design schedule from the system designer then 'at a design temperature of 50' is likely to mean at a flow temperature of 50, ie a deltaT between radiator and room of 30.

If its the spec from the radiator manufacturer then 'at a deltaT of 50' (or just '50' is likely to mean  means when the temperature of the radiator (ie the flow temperature) is 50C higher than the room, ie at a deltaT between radiator and room of 50.

Hopefully that helps you interpret the documentation.

@jamespa Thank you - I find it very confusing.

What do you think of my radiator spec for being able to run at lower flow temps than the 50º design temp? This is what I'm trying to establish. 

I'm also now worried that the bathroom radiator I am intending to buy is not good enough - I used its output in watts at DT 30 to workout if I could run it at a low temp - 35º flow temp - to match the heat loss. 

In the schedule DX = P+; DC = K2 and SC = K1

@editor The Cosy 6 has been mentioned but I do not want that and it is too big for the space really so the alternative is the Daikin 6kW. Also to make installation more straightforward I have decided to position it on the path around the house and extend the path around it, thus avoiding a trench.

However as yet no proposal and installation if they are now happy to do it early next year?

At the moment I am running the boiler at 37C to see how it copes, it allows a flow temp of as low as 30. I'll do some experiments with these cooler temps.

Posted by: @lucia

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@jamespa Thank you - I find it very confusing.

What do you think of my radiator spec for being able to run at lower flow temps than the 50º design temp? This is what I'm trying to establish. 

I'm also now worried that the bathroom radiator I am intending to buy is not good enough - I used its output in watts at DT 30 to workout if I could run it at a low temp - 35º flow temp - to match the heat loss. 

In the schedule DX = P+; DC = K2 and SC = K1

-- Attachment is not available --

 

It looks like B1, B2, Hall, Kitchen are bigger than needed for the design flow temperature so will work at lower FT.  Living room*2 are smaller than needed for the design flow temperature so presumably the designer is relying on room to room heat transfer to make up the difference. Currently the total line shows the house as a whole being balanced so I wouldn't expect much opportunity to run at a lower temp unless the whole house loss is overestimated

If you could upgrade the DX radiator in the living room to DC that would be an 'easy' improvement.  Beyond that you would need to tackle the rads in the living room more seriously.  Could you make them physically bigger?  Would K3 work (typically 200mm + thick so can be intrusive)?  Would you consider a fancoil?

Towel rails (if that is what you are contemplating) are pretty much useless for low temperature heating.  Better to use a standard radiator with a hanger.

@lucia 

My Octopus radiator schedule gives all rooms radiators between 129% and 165% coverage.

Heat loss 5400, radiator output 6485.

Your bedroom seems way oversized and shower room way undersized, but are they adjoining to balance both out?

I'm having mine fitted next week so hopefully can run much lower than 50° but if not I'll slowly swap them out for bigger.