Thanks.

As it happens my local plumber is fantastic. We were talking about heat pumps when he last serviced my boiler. He was quite clued up but I suspect too near retirement to change his business. The son who works with him might I suppose.

I did ask if he wanted to buy my old boiler when replaced as he's known it from new. Not allowed apparently. He'd like it for spares though. Unfortunately MCS insist they're 'recycled'.

Posted by: @springswood

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Thanks.

As it happens my local plumber is fantastic. We were talking about heat pumps when he last serviced my boiler. He was quite clued up but I suspect too near retirement to change his business. The son who works with him might I suppose.

I did ask if he wanted to buy my old boiler when replaced as he's known it from new. Not allowed apparently. He'd like it for spares though. Unfortunately MCS insist they're 'recycled'.

Thats correct, taking your boiler out and fitting it somewhere else is not seen as taking one more boiler system off the gas grid as it will be back on the grid, I get that it might not make sense as were thats second hand boiler would have gone its likely a new boiler will go, but this is also to do with the boiler sales fines, if it gets fitted somewhere else the manufacturers dose not sell a new one which has a kind of tax levy.  

@majordennisbloodnok 

I understand the EPC template is being reviewed (and perhaps the process as well). If missing data etc is added to it it could fulfill the purpose of the heat loss. 

I would not be as harsh on the EPC assessors and it seems to me many do heat loss surveys as well.

Still, our example may not be atypical. We had an EPC done after the last upgrades. Whenever ASHP installers use it for an initial estimate, they calculate a heat loss between 6.1 and 7.4kw (-2C). The heat loss survey we had arrived at was 5.1kw at -2C, in line with what the half hourly gas usage indicates. The consequence of being over 7 is to place our home in the larger size heatpump category (eroding some of the benefit of insulation). 

Posted by: @batpred

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@majordennisbloodnok 

I understand the EPC template is being reviewed (and perhaps the process as well). If missing data etc is added to it it could fulfill the purpose of the heat loss. 

I would not be as harsh on the EPC assessors and it seems to me many do heat loss surveys as well.

Still, our example may not be atypical. We had an EPC done after the last upgrades. Whenever ASHP installers use it for an initial estimate, they calculate a heat loss between 6.1 and 7.4kw (-2C). The heat loss survey we had arrived at was 5.1kw at -2C, in line with what the half hourly gas usage indicates. The consequence of being over 7 is to place our home in the larger size heatpump category (eroding some of the benefit of insulation). 

@batpred, a review of the EPC template would be a good thing, but I'm less concerned about what's supposed to be captured in the survey as much as what's captured in practice.

I agree there are plenty of EPC assessors who do a good job; my last EPC is the result of one of those. However, the variation in quality between surveys is woeful and so there are far too many EPCs that don't stand up to an even cursory comparison with reality. That uncertainty is what makes all EPCs - good and bad - impossible to rely on for heat pump system design purposes. If an acceptable level of consistency could be applied across all assessors, the template review you mentioned would probably help a lot.

The current EPC process isn't fit for purpose but to be fair it was supposed to be nothing more than the appliance efficiency sticker for houses as part of HIPS, which the RICS at the time and Cameron together then wrecked so surveyors still get paid multiple times per house. The new EPC process is supposed to make it rather more aligned to reality.

I agree they are a joke - the one for the house we are currently rennovating said it was rendered solid stone walls, and in fact it's cavity walled brick but there's no easy way for a tickbox form filler to figure this out on the property in question so they guessed.

Not surprised about the MCS on boilers, they still to this day won't allow second hand solar panels to be fitted in an MCS compliant install, which would be fine if the energy companies actually followed the rules on SEG payments instead of demanding MCS. Does mean they are scrapping perfectly good boilers which might have been used to upgrade old boilers that are otherwise staying in use as the old ones. 

A big part of the problem IMHO is that most UK houses never had a built in heating system prior to central heating. Going gas fires to central heating or coal to central heating wasn't as disruptive as you didn't have to rip one our for the other and bits of your heating failed independently. So apart from fringe cases this is the first time. Boiler to boiler works because you just look at the size installed last time and shove in the same or bigger. Heatpump ought to be similar once you get it correctly installed the first time.

Good points @etchedpixels 

And it occurred to me that the trust thing with installers is partly because I don't know anyone with a heat pump. In my immediate neighbourhood of around 100 houses there are no heat pumps and, as far as I know, 100 gas boilers. Mine is only the 2nd EV. 

Posted by: @ashp-bobba

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@jamespa Yes, sort of, DNO is notification but they can refuse in rare cases so it is also like getting permission. We know which one will get refused though so its not a surprise if it happens, shared services, looped services, incorrectly Earthed service and 60amp or below main fuses get refused until an upgrade is done by the network operator and they can end up charging you for this.

I may understand a delay, but a refusal seems plain wrong. Even if there were very restrictive conditions of that supply to start with. Like a 60A fuse supply, able to run three 3kW convectors plugged across a few socket ring circuits will break no sweat with any domestic heatpump? 

Forcing the heatpump installer to carry this "weight of dealing with a limited supply" is essentially telling me one thing: that the reduction of emissions likely when using a heatpump is in practice not important enough for policy makers. 

Posted by: @ashp-bobba

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@jamespa Yes, sort of, DNO is notification but they can refuse in rare cases so it is also like getting permission. We know which one will get refused though so its not a surprise if it happens, shared services, looped services, incorrectly Earthed service and 60amp or below main fuses get refused until an upgrade is done by the network operator and they can end up charging you for this.

Is that the case even if its <16A per phase (which our 6kW heat pump will be)

The web guidance on this is definitely inconsistent and I have not yet managed to find the source documents, perhaps you (or @transparent ) can point me at them

PS: There seems to be a flow chart produced by the ENA here which I imagine is close to definitive.  The key 'gotchas' seem to be looped service and max customer demand >60A per phase. (or cut out rating whichever is lower), otherwise its connect and notify (within 28 days) for up to 32A.

I guess if customer has an induction hob, electric oven, EV charger and immersion heater you might get above 60A, although EV chargers these days typically come with CT clamps and power limiters so effectively can be discounted.  Not sure what the diversity rules are for the others but I know I have never, ever got close to 60A, in fact I have to work really, really hard to get above 40A even when Im trying for one of the 'free' sessions and I cant sustain that for very long.  

I must say this side of it is really bizarre since I can (well, a 'competent person' can) can connect a 9kW shower without any DNO requirements whereas a 6kW heat pump draws only 3kW max.

Posted by: @jamespa

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PS: There seems to be a flow chart produced by the ENA here which I imagine is close to definitive.  The key 'gotchas' seem to be looped service and max customer demand >60A per phase. (or cut out rating whichever is lower), otherwise its connect and notify (within 28 days) for up to 32A.

Thanks for sharing. 

Treating a domestic heatpump (that will often be below 16A, which as 3.7kW means the heatpump would deliver well over 10kW of heat) in the same chart as an EV charger must have a good technical justification. Or not!

Why would a heatpump installer have to check the DNO installation (is it acceptable the DNO would not know it..)?

I also do not see a reason for a pump below 16A to even have to be notified. I do not remember notifying my kettle.. 😀 But if the notification could be done by an MCS installer or a consumer (so not requiring an electrician), perhaps that would not be onerous..  

Over 16A it could be getting close to an EV charger... But if a DNO provides a 60A fuse, they should be ready for people to actually use it. 

Posted by: @jamespa

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I must say this side of it is really bizarre since I can (well, a 'competent person' can) can connect a 9kW shower without any DNO requirements whereas a 6kW heat pump draws only 3kW max.

Good point, again, renewables seem to be treated as special as if there was no net0 target..

Posted by: @batpred

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Posted by: @jamespa

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I must say this side of it is really bizarre since I can (well, a 'competent person' can) can connect a 9kW shower without any DNO requirements whereas a 6kW heat pump draws only 3kW max.

Good point, again, renewables seem to be treated as special as if there was no net0 target..

 

Just like the planning rules sadly.  Its classic fear of the new/excuse to regulate, but not helpful.

That said and in fairness any electrician fitting any piece of fixed plant is presumably expected to assess whether the design load exceeds the cut out value so that element is really not special. 

The issue here seems to be to be assessing the load of the the ring main and Im not sure how electricians do that.  We have 4 (to do with the history of the house, not because we need 4) and I have seen one set of rules which says you allow 100% for the first ring then 40% for each of the others.  This puts our 'requirement' over 70A for the ring main alone, which is obvious nonsense . 

Not sure about the significance of the looped in supply gotcha.

Given that the reality is that 60A is very unlikely to be exceeded, I suspect that this 'problem' is amenable to a rule-based solution covering 90%+ of cases for our sub 6kW house, if a few out of the box thinking electricians put their mind to it, not least because the electrical regs award a high degree of discretion to the electrician.   As to whether we can find a few out of the box thinking electricians, that's another matter.  

Posted by: @batpred

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But if the notification could be done by an MCS installer or a consumer (so not requiring an electrician), perhaps that would not be onerous..  

It can and is done by the installer, dead simple process.  It was formerly possible for a householder to do it but Im not sure if that is still the case.

Posted by: @jamespa

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The issue here seems to be to be assessing the load of the the ring main and Im not sure how electricians do that.  We have 4 (to do with the history of the house, not because we need 4) and I have seen one set of rules which says you allow 100% for the first ring then 40% for each of the others.  This puts our 'requirement' over 70A for the ring main alone, which is obvious nonsense . 

Thanks. I am struggling to reconcile net0 with policymakers settling for reactive action from the DNOs. Can anything else but preemptive work from the DNOs be appropriate policy, not even considering the uncertainty that this is adding to scaling the deployment of heatpumps? Plus current practice is clearly reducing the likelyhood of retrofit of a heatpump by the home owner after a boiler failure. 

Specially as if a DNO is concerned their equipment may not allow a 60A supply to have 16A used as baseload that is a risk when plugging 3*3Kw convectors (of the type Cadent left us with when they cut off our supply at some point, they apologised they could only leave us with 3)! 

On the plus side, the estimated 'opex' after our ashp retrofit seems healthy. Extrapolating from 30 min gas usage over the last couple of years, our heating and hot water costs will be reduced by between 22 and 70% (the highest estimate requiring an extra 16kwh battery).