@squeakysim, welcome to the forums. Please feel free to start a new thread when you have questions.

24k for a heat pump installation seems extraordinarily high. Would be good to know how they came to that figure.

@editor when I was looking for quotes I was told "An ASHP system will be in the region of £33 – 35,000 +VAT." This was because they assumed I'd need a two heat pump cascading system, based on an out of date energy performance certificate.

Although it could be viewed as a "polite" way of telling me they weren't interested in my business, I wish they wouldn't do this. It gives people an inflated idea of how much heat pumps cost, and provides hostile anecdotes for the likes of the Express. My Carnarvon is hardly insubstantial, but cost a lot less than that!

@squeakysim hi we had an ASHP fitted 8 months ago and the cost was the same  we are in a 4/5 bed Scottish cottage and our old LPG c/h wet system had to be ripped out and the whole system replaced inc pipe work. Because of the add on nature of our house over the years it was a costly excercise but as we had several quotes we knew the costs were accurate. With regard to it being too expensive that is something that did not affect our plans because it was part of a long term plan to bring the property up to EPC c rating in view of the impending discussions on govt/lenders looking at old/energy inefficient properties. Incidently we also fitted an 8 KwH solar field which has produced well over 3000kwhs since 20th June - the only problem being the batteries which are still on order. 

@squeakysim Hi, it would be useful to know a bit more about the house and its current heating system. In my current house rather than replace all the CH pipes, Ive decided to install an Air to Air heat pump in our large kitchen. Costs are much lower and useful for rooms that might not be used all of the time.

@editor he only had a quick look around before he came to say how much work he thought would be involved, not just that but the amount of upheavel. So it was a crude calculation at best, but he said it was based on similar sized installation they'd done plus the amount of additional work he believed was required e.g. increasing the size of every radiator (12+), cutting a bigger loft access hole for the water tank to be housed - so a lot of extra labour. Plus they only install the Steibel Eltron ASHP (they say due to it's efficiency), and apparently is also more expensive than most others out there (around 12k I think). But, still it does seem pretty high!

Hopefully, I can aquire the knowledge I need from here to find a better solution! I think I'm going to lean toward HTHP, but if that's not viable I'll also look into AAHP to combine with gas heating, so i'll be interested to hear the efficiency of your unit @bontywood! But I'll start a new thread for all that I think!

Posted by: @squeakysim

The solar installation we are looking at is 8.47kWh array with 9.3kWh batt storage, the intention was to attempt to cover the estimated ASHP usage...

As you're in Australia I don't know how much you are aware of the UK rules for grid-connection. Does G98 mean anything to you yet?

Unless the property happens to be located on a particularly favourable part of the regional network, you would expect the Distribution Network Organisation (DNO) to allow connection to their grid provided that export was restricted to 16A per phase (3.68kW) maximum.

If your PV panels are connected to a grid-tied inverter, and your storage battery is also connected (bi-directionally) to the 240v mains, then you'll end up with two devices in the home which have export capability. Each will require their own G98 approval from the manufacturer. And the entire installation will require G99 consent from the DNO.

The DNO checks this using a database held by the Electrical Networks Association. Each device (solar inverter and battery) must have their G98 certification present on that database. There must also be an approved mechanism for export restriction identified on the ENA database. In other words, the two devices have a hardware/software 'agreement' between them that they won't feed more than 16A back to the grid.

You might actually want zero-export. The cash-back is very small, and you'd probably prefer to use all that is stored within the home.Excess generation can be used to heat domestic hot-water (DHW) via an approved Diverter.

Another alternative is to buy a storage battery which can directly accept input from your solar-panels (DC connected). That removes the requirement for a separate solar-inverter. Now there's only one device in the home which has the capability to export. It will have its own G98 certificate. G99 approval is no longer required.

Also have a look at how I introduced this topic over on the thread about Domestic Hot Water and Space Heating.

That refers specifically to houses with heat pumps.

My current 'best suggestion' is to install a hybrid off-grid storage battery and run the heat-pump from that. Such an installation has no possibility of exporting to the grid, and therefore doesn't require any DNO application.

Please follow up these points over on the other topic rather than here on the 'Hello' thread. That will enable others to find our discussions in future.

@transparent that was a lot of words and terms of which many will require some further research! 😆 

I will say though, that the solar install has been designed as part of the Solar Together scheme which is a group buying scheme in collboration with many councils. And I do recall a presentation I watched which they stated they take care of the DNO application.

That said, I will look into the point you raise, so thanks!

Now to work out where to start my thread....!

I hope you'll find that much of the required research has already been done for you! The points you raise are completely on-target for this Forum. Many answers already exist here, and there's a wealth of experts who will jump in to clarify what's required.

Please hold me to account if I use terms/abbreviations for which there isn't an explanation. I try to employ the 'correct' terms because that enables you to use them in other searches. But I also attempt to use the full version of an abbreviation when it gets mentioned for the first time.

To add clarity I also use graphics. The two diagrams in my previous post are deliberately simplistic. I'll can expand on them as and when a discussion requires it.

Posted by: @squeakysim

the solar install has been designed as part of the Solar Together scheme

That may or may not provide the answers you require.

I currently have four rooftop solar-PV arrays supplying two different storage-battery trials.

The one which is financially unviable is the professional one which uses a well-known brand of British-built storage battery. At the present electricity tariffs, this costs me almost £300/year to buy in the electricity to keep it running on those days when there is insufficient sunshine to store anything!

Just because a product comes with a healthy list of certificates and awards doesn't mean it's any better than something which your local electrician puts together for you! Different houses' requirements are unlikely to be entirely satisfied by the same short-form list of equipment for which a buying consortium has arranged a discount. You still require a system designer, and a PAS2035 survey against which the alternative quotes can be evaluated.

@chris-a, that's crazy and I agree. Giving overinflated prices for heat pumps doesn't help the industry that is shrouded in uncertainty.

Find an installer who installs something other than one of the most expensive and difficult-to-source-spares-for brands of heat pump.

Install any modern ashp properly and you’ll be getting 3.8-4 on a scop. No need at all to go with something expensive from stiebel.

Thanks to whoever moved my thread, I was wondering what had happened for a moment!!

@transparent a couple of questions for you:

Posted by: @transparent

Unless the property happens to be located on a particularly favourable part of the regional network, you would expect the Distribution Network Organisation (DNO) to allow connection to their grid provided that export was restricted to 16A per phase (3.68kW) maximum.

I've read up on this a bit, although don't full y understand how this could pan out in our situation.Is your main concern here that we'll be generating more energy than we'll be able use/store/export? Or just that we need to be sure we make the relevant G98/99 submission?

Posted by: @transparent

Another alternative is to buy a storage battery which can directly accept input from your solar-panels (DC connected). That removes the requirement for a separate solar-inverter. Now there's only one device in the home which has the capability to export. It will have its own G98 certificate. G99 approval is no longer required.

The inverter included in our setup is a SOLIS HYBRID / AC COUPLED INVERTER.

Posted by: @transparent

Just because a product comes with a healthy list of certificates and awards doesn't mean it's any better than something which your local electrician puts together for you! Different houses' requirements are unlikely to be entirely satisfied by the same short-form list of equipment for which a buying consortium has arranged a discount. You still require a system designer, and a PAS2035 survey against which the alternative quotes can be evaluated.

Hmmm... this is a tough one. I have probably made a big mistake not trying to obtain quotes from other installers while we've been waiting the last 4 months for this survey. Everywhere seems to be totally backlogged with enquiries now, so getting comparative quotes will be really difficult now. Especially as this offer we have has a limited timeframe. I totally hear your point though... The PAS2035 survey you mention, is that something that all suitable installers would be able to provide?

Posted by: @transparent

Also have a look at how I introduced this topic over on the thread about Domestic Hot Water and Space Heating.

Do you have the link for this, as this one doesn't work...?

Have another go... I've redone it and it works for me!!