Erm... I carefully chose the adjective many when referring to installers.
I deliberately didn't write 'major' or 'the majority of' installers.

And when I'm using the word installer, I'm thinking of the hypothetical "Dave and Bert from Riventree Heating", who are contractors doing the work.
Whereas OVO and Octopus are Energy Suppliers who might be choosing Dave and Bert for the job.

I've never met Simon Murray who's just written this Editorial Red Flags to Avoid When Considering a Heat Pump Installation, but I have gained confidence about his company's technical capabilities by reading what he's posted.

Don't 'give up' @ellyse but please do start enquiring about what is being proposed for your particular house.

Also, use some imagination.

If your pipework is going to be run in the attic and has to descend down the wall to a radiator, then why not consider a tall radiator as a feature?
Would that look better and save wasting wall-space with square trunking containing pipes?

Browse online and see what's available.
Ask if it's possible to have a tall radiator with the connections at the top.
Such a design might exist.

For us it is very confusing.  I have tried to 'learn' some about these by watching videos by the 'heat geeks' and reading alsorts. 

This mini-estate has no gas.  It was built in the 1980's as all electric. 

1. There have been 3 different surveys done of this property, all apparently for this installation.

2. They decided loft insulation is adequate and cavity wall insulation is adequate. 

3. They will decommision the immersion tank (no way to remove it as loft hatch is too small). 

4. Water tank will go in the back bedroom in the corner. 

5. heat pump will go outside the back bedroom next to the wall.

6. All our current electric wall heaters will be removed. Including the towel rail version from the bathroom. 

7. Our present extraction fans in kitchen and in shower have been deemed not good enough so will be replaced. 

8. Each room will get 1 radiator, except the lounge which will get 2 radiators. 

9. All pipework will use the attic space as much as possible but then run down the walls to be covered with trunking. 

10. Solar panels are going on the roof. As we are end-terrace bungalow they have the option to use 2 directions on roof. The first gets early morning to midday sun.  The second gets midday to evening sun.

11. There will be a box installed on the wall behind the front door that I believe is for the solar panels but no idea if it's just a control panel or an inverter or has any battery storage. 

Ovo is in charge of the grant and choosing the company for installation.  However our electricity supplier is Octopus. 

That is the extent of the info I've been able to get from them so far. Every time a 'surveyor' visited we asked many questions. Each seemed to have limited permissions to discuss it. 

Posted by: @transparent

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The DHW cylinder will also have an electric immersion heater in it.
That's not 'efficient' but is necessary for a number of reasons:

• if the external part of the heat-pump should ice up in winter, there needs to be a way for the system to de-ice it

Just to correct couple of things 

DHW cylinder takes no part in the defrost cycle. The energy for defrost is taken from the central heating circuit only. A 4 way valve within the heat pump reverses (goes in to cooling mode) and extracts heat from water thereby heating the condenser to melt ice formed there. The process takes around 5 minutes.

The hot water cylinder should be larger than the one you currently have in use. Reason it stores water at a lower temperature - around 45 to 50 degs. The heat lost is low, mine at 50 is cold to touch.

Lastly be careful if they install thermostat or radiator trv in every room as it is likely the flow temperature will be left set way to high and room temps control via bouncing of the thermostat. If they do be prepared for some fine tuning before winter. At least you will get the basics for free.

For lowest running costs you need

1. An open system for max water flow

2. Run ideally 24/7 on a set house temperature. Set all thermostats or trv's to max so they do not interfere. Once you have things adjusted you can play with setbacks and look at the effect on running cost.

3. Run weather compensation, this will require some fine tuning. So get the information from the installer of how to do it.

I'm going to pick up a few of those points @ellyse

Posted by: @ellyse

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1. There have been 3 different surveys done of this property, all apparently for this installation.

Every time a 'surveyor' visited we asked many questions. Each seemed to have limited permissions to discuss it. 

I don't think that's good enough.

This is one of the points which got picked up in the Householder Feedback during the Electrification of Heat Trial.

You should be given a copy of the survey which assesses the heat-losses from the house.
That's the one from which they calculate the number & size of radiators.

Providing documentation is a requirement stipulated in Part-L of the Building Regulations:

Do you see the sentence: Help the occupiers... verify that any Fixed Building Services... comply with the energy performance requirements of the Building Regulations.

You can't verify the installation unless you start from that Heat Loss Survey.

Posted by: @ellyse

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2. They decided loft insulation is adequate and cavity wall insulation is adequate. 

It is all too common for the level of loft insulation to be assessed by a surveyor sticking his head into the loft.
The usual problem is that loft insulation hasn't been pushed down into the eaves, where it must connect to the wall insulation next to the wall-plate.

Frequently the Insulation Installers tell householders that they can't do that because it would prevent the airflow from the soffit board, and condensation will rot the rafters.

However, there are plastic Ventilation Trays which should be fitted.
If there are no ventilation trays visible, and you have the required 250mm depth of insulation, then it's unlikely that the insulation has been correctly/fully fitted.

That needs fixing now because you will otherwise have a 'cold edge' to the ceilings.

Posted by: @ellyse

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5. heat pump will go outside the back bedroom next to the wall.

A heat pump requires a minimum 300mm between itself and the wall behind it.

It must also be at least a meter away from the boundary wall.

Posted by: @ellyse

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7. Our present extraction fans in kitchen and in shower have been deemed not good enough so will be replaced. 

They need to say what the replacement is.

There are single-room ventilation fans with heat-recovery.
They allow an exchange of air whilst minimising the amount of heat lost to the outside.

Posted by: @ellyse

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10. Solar panels are going on the roof. As we are end-terrace bungalow they have the option to use 2 directions on roof. The first gets early morning to midday sun.  The second gets midday to evening sun.

Many solar inverters have two independent inputs.
In your case, one set of panels on the SE elevation would be connected to input-1
and the panels on the SW elevation to input-2.

They should not fit panels to the two roof sections and then join them into a single input to an inverter.

Posted by: @ellyse

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11. There will be a box installed on the wall behind the front door that I believe is for the solar panels but no idea if it's just a control panel or an inverter or has any battery storage. 

That should be the solar inverter.
You need the model number of this.

We can then look up the specifications and make recommendations to you.

Besides the work being administrated by OVO, I really think your Council needs to be involved in scrutinising what's being installed.

Roughly whereabouts are you geographically?

Or what's the name of the Council which operates as the Local Planning Authority (LPA)?

Council is Rochdale. 

Not been given any paperwork yet. However they are working on 1st wave atm.  We will be 2nd wave of installs. 

Neither of us is capable of getting into the loft to check the roof-edge insulation. Can and will ask when they come to start. 

Thank you @ellyse

Rochdale isn't an area I'm familiar with, and I don't have the network maps for your regional distribution grid.

However, if I were in your position, I would be sending an email to the Borough Councillor(s) representing your ward and tell them that you're receiving free insights and technical assistance from specialists on the Renewable Heating Hub forum. Provide the URL for this particular topic so they can see what we're saying.

Rochdale Borough Council operates a Cabinet System.
Cllr Tricia Ayrton holds the portfolio for Climate Change and the Environment.
It's possible that the heat-pump and solar panel installation project is being orchestrated by staff working under her directive.

Being a Councillor can be a daunting task. It's made harder because

• members of the public only tend to make contact when they have a complaint
• you don't get told useful/interesting things which are happening in your ward

You have the opportunity to remedy those two issues for your local Councillor(s).

The one point of what you’ve shared so that concerns me most is the phrase “each seemed to have limited permissions to discuss it”. Any installer or surveyor who is confident and competent will be comfortable explaining (several times if necessary). But if they don’t it could mean they are lacking either, or the job has been bid at a price which is so tight that they can’t take the time. Either may mean a less than ideal installation. 
Have they ever explained why so many visits are needed? Two should be plenty, one for the heat loss survey and one for the solar planning since plumbers and electricians are not always so broad. You will have missed (fortunately) the sales pitch visit. 

Someone earlier mentioned a battery would be a good idea. That is worth considering if you have some savings because it allows you to buy electricity at a cheaper rate. Standard rate electricity can mean higher bills, even than your present (presumably) storage heaters.

@judith A battery not only helps you to choose the cheapest time to consume but also helps by taking some pressure off the NG peak demand. I realise that any one consumer may only be a feather on the back of the ‘duck curve’ but every little helps. Regards, Toodles.

@toodles - you might want to check @judith's credentials before posting further on that point!

Even the text at the foot of her posts gives an indication of high technical competence 😎 

@transparent I am sorry Transparent and Judith, that was not my intention but I was attempting to add a comment for @ellyse. I am using an highly magnified version of the page to be able to read it with my poor vision and it appears that the text at the foot is stripped out so I am unaware of competence anyway. I’m sorry if my reply was insulting, no such intention was meant. Regards, Toodles.

Posted by: @transparent

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@toodles - you might want to check @judith's credentials before posting further on that point!

Even the text at the foot of her posts gives an indication of high technical competence 😎 

What's all this nonsense about? Are you saying people are not worthy of replying, because someone is investigating getting an ASHP.

I believe that everyone who is considering getting a heat pump, whether free like @ellyse or paying about half (us with the BUS grant) should investigate them thoroughly. It’s so much better to learn before installation than afterwards.

I do have a technical background (physics and systems engineering) so I am able to recognise the expertise and commitment of contributors to this forum. Thank you to you all, you are very much appreciated. 
However I am not the world’s best technical author and two finger typing can always go wrong so if someone finds they need to supplement or correct what I’ve written that’s totally fine by me. I rarely take offence and I know for certain @toodles meant none (exchanged pms) so there’s no problems at all.

What we should all do is focus on what @ellyse both wants to know and needs to know to get the best from a free install.