Heat Pump Sizing?

FreeBear

michaels said:

Here is my attempt:

12.5kw 'Dream' heat pump £1600

SWR cable, fuse unit £100

You'll also need Part P sign-off for the electrics (can be included in Building Control sign-off on the whole install).

You may need to upgrade your main fuse and possibly require DNO approval depending on other high load devices you have.

Just whacking in a heat pump is not a simple job - There is a bunch of paperwork that needs to be done, along with quite a bit of hidden costs.

michaels

FreeBear said:

michaels said:

Here is my attempt:

12.5kw 'Dream' heat pump £1600

SWR cable, fuse unit £100

You'll also need Part P sign-off for the electrics (can be included in Building Control sign-off on the whole install).

You may need to upgrade your main fuse and possibly require DNO approval depending on other high load devices you have.

Just whacking in a heat pump is not a simple job - There is a bunch of paperwork that needs to be done, along with quite a bit of hidden costs.

Steady draw is less than an immersion and similar to a plug in electric radiator that does not need any special DNO permissions - I know rules is rules

matt_drummer

michaels said:

FreeBear said:

michaels said:

Here is my attempt:

12.5kw 'Dream' heat pump £1600

SWR cable, fuse unit £100

You'll also need Part P sign-off for the electrics (can be included in Building Control sign-off on the whole install).

You may need to upgrade your main fuse and possibly require DNO approval depending on other high load devices you have.

Just whacking in a heat pump is not a simple job - There is a bunch of paperwork that needs to be done, along with quite a bit of hidden costs.

Steady draw is less than an immersion and similar to a plug in electric radiator that does not need any special DNO permissions - I know rules is rules

You have a solution then, go for it.

Heat pump is not a household name but cheap enough to buy replacements as and when necessary.

That heat pump will draw twice what an immersion does when it's cold, especially at higher flow temperatures.

I assume you will be re-using components such as magnetic filters, safety valves, expansion tanks, stuff like that?

Any pipe insulation?

What are you going to do when it is freezing outside, glycol or anti frost valves?

If you ever plan to sell the house you would be best advised to get some sort of check on the electrics at the very least.

I haven't researched it but I am pretty sure that DNO approval and local authority sign off are required.

What about planning permission, certain that it's not necessary?

You have a gas boiler? Obviously you can't disconnect that yourself, I assume you are not Gas Safe registered?

michaels

Lots of people use very similar heatpumps to heat their swimming pools.  Don't suppose there has been much DNO approval nor building control sign of for those....

matt_drummer

michaels said:

Lots of people use very similar heatpumps to heat their swimming pools.  Don't suppose there has been much DNO approval nor building control sign of for those....

You can do what you like as long as you don't get caught, and even then you can fix it.

A heat pump that size with an immersion running at the same time will pull close to 40 amps at their peak.

You might want to consider a volumiser as well or you could find defrosting an issue.

The water heated for a swimming pool will be at a much lower temperature than you will need for heating, that probably draws much less power.

I doubt many heat their swimming pools when it is -5c outside, but I don't know, maybe they do.

I would imagine that anybody with a swimming pool they wanted to heat would have the resources to get the heat pump installed professionally.

I assume your proposed location on the flat roof is not going to attract any attention from neighbours?

FreeBear

matt_drummer said:

michaels said:

Lots of people use very similar heatpumps to heat their swimming pools.  Don't suppose there has been much DNO approval nor building control sign of for those....

You can do what you like as long as you don't get caught, and even then you can fix it.

Councils now have up to ten years to start enforcement action for any planning & BC breaches.

Tried to find an installation manual & specs for this Dream HP - Apart from some basic numbers, I can't find anything of note.

matt_drummer

What does this Dream heat pump modulate down to?

I looked on ebay.

The seller will be paying ebay fees assuming that is where you are getting it from?

If that is 10% then that is a net income to the seller of £1,440

The one I looked at delivers within 50 miles of their base so that is another cost to them.

Whether there is VAT, I don't know.

But realistically, a 12.5kW heat pump for £1,000.

It doesn't scream high quality, but then it's also not necessarily bad, it could be really good.

But for the same cost as a professional fully backed installation (with a known heat pump, a tank, radiator upgrades and all properly certified) from Octopus I have to wonder whether it is worth the trouble?

Nick_Dr1

Isn't their a thread on this forum here where someone installed a heatpump and the council have ordered it to be removed because of noise infringements? Heatpumps are permitted development but within certain constraints. Its easy enough to check.

You do need DNO sign off but that is usually trivial as long as you have sensible electrics and no heavy draw such as EV chargers already installed. Even if you have an EV charger this is not necessarily a show stopper as they can be fitted with load moderators. Heatpumps can't (yet).

But as said, you can do what you like and the only problem will occur if you are caught infringing something. However, it will be an impediment to selling later because solicitors will ask to see relevant paperwork (because they can). You may get it retrospectively but there's no guarantee and it will result in delay.

NedS

michaels said:

FreeBear said:

michaels said:

Here is my attempt:

12.5kw 'Dream' heat pump £1600

SWR cable, fuse unit £100

You'll also need Part P sign-off for the electrics (can be included in Building Control sign-off on the whole install).

You may need to upgrade your main fuse and possibly require DNO approval depending on other high load devices you have.

Just whacking in a heat pump is not a simple job - There is a bunch of paperwork that needs to be done, along with quite a bit of hidden costs.

Steady draw is less than an immersion and similar to a plug in electric radiator that does not need any special DNO permissions - I know rules is rules

It's not so much about the total current draw (although this does need to be assessed and determined to be within safe limits), but more about the fact heat pumps and EV chargers cause significant losses at the local substation due to phase-imbalance and harmonics.

NGED's RIIO-ED2 licence agreement with Ofgem requires them to reduce those losses. They can't hope to address and reduce what they don't know about if you haven't informed them. This is why G98 notification is a requirement under install and notify arrangements assuming all other relevant conditions have been met.

https://yourpowerfuture.nationalgrid.co.uk/riioed2-business-plan

The rules exist for a reason, although I understand those reasons may not be immediately apparent to the average home owner.

michaels

NedS said:

michaels said:

FreeBear said:

michaels said:

Here is my attempt:

12.5kw 'Dream' heat pump £1600

SWR cable, fuse unit £100

You'll also need Part P sign-off for the electrics (can be included in Building Control sign-off on the whole install).

You may need to upgrade your main fuse and possibly require DNO approval depending on other high load devices you have.

Just whacking in a heat pump is not a simple job - There is a bunch of paperwork that needs to be done, along with quite a bit of hidden costs.

Steady draw is less than an immersion and similar to a plug in electric radiator that does not need any special DNO permissions - I know rules is rules

It's not so much about the total current draw (although this does need to be assessed and determined to be within safe limits), but more about the fact heat pumps and EV chargers cause significant losses at the local substation due to phase-imbalance and harmonics.

NGED's RIIO-ED2 licence agreement with Ofgem requires them to reduce those losses. They can't hope to address and reduce what they don't know about if you haven't informed them. This is why G98 notification is a requirement under install and notify arrangements assuming all other relevant conditions have been met.

https://yourpowerfuture.nationalgrid.co.uk/riioed2-business-plan

The rules exist for a reason, although I understand those reasons may not be immediately apparent to the average home owner.

I would have thought my induction hob that comes on and off every few seconds drawing massive current would be a much harder problem for the grid than a heat pump that admittedly starts high but then runs pretty much constant for a decent period.

Edit: Tried the link but rapidly lost the will to live as it was about 3 words per scroll