Wil

Ah yes, I missed the sqft, not sqm. Still 512m2 is pretty damn impressive! Unless you can get a large scale turbine PV will outperform it- I have a 1kWp unit and on its best day ever it managed 2kWh of generation often the daily is nothing or a few tens of Wh. The 5kWp PV regularly outputs 20-25kWh peaking at 35kWh in a day. The turbine isn’t ideally sited, but you’d need planning permission for a full tower and a much bigger unit to get a decent output. I’d have to say the PV looked better at that point.

Can I come see it, I’m near Titchmarsh and being nosy about a 9000m2 Barn conversion? 🙂 Sounds like there’s lots to consider with GSHP and secondary circuit. Do you have an PV or anything you can divert into the newly wired immersion?

TBF the biggest issue with the Powerwalls is that they aren’t a UPS and can allow a brownout as the power drops which means a lot of stuff switches off. Once they get hold of the load they can output 10kWp (14 for short duration) and keep the basic inverter online so the power keeps running. The power drop almost always gives a big enough spike to take out my main 100mA RCD though, so they can’t return to grid until I reset it. I’m very jealous of some of the consumption figures- I imported 20.1MWh last year…

Impressive Mike! My solar only produced 785kWh (unshaded SSW array in the Midlands) in May! £150 back would be a pretty nice payday! My installer has now enabled export on the batteries so I can dump what’s left in them at the end of the day at 15p and then immediately charge them back up at 7.5p. Will see how that goes for a bit before deciding how much I want to fully cycle them every day.

I’m assuming that I would have used the import energy anyway and been paying for it. So every penny in export is effectively ‘gain’ from my previous situation. It’s probably too simplistic as the solar charging the battery would have meant less charging the following night. Either way- today I’m at 25.4kWh import and 20.5kWh export so figure I’m up for the day. The £250 is also a LOT less than I would have paid for an MCS install- am I allowed to offset that cost?

Turns out by changing the tariff in my Tesla App, it’s sorted itself out and is now exporting all the solar and just slowly discharging the battery to cover the house. Haven’t seen what it does when the house loads look like they’re going to exceed the battery capacity during the day but got 13kWh of export yesterday vs 34.3kWh of off peak input (house/car/battery charge). Once it settles down I should be able to see what my break even on the £250 is going to be! 1667kWh of export either way.

I can’t export my battery sadly as it was set up prior to any export agreement. I let the HW charge from the ASHP whenever it needs but have been dumping solar into it until recently. You make a good point though- I could export the batteries to 30% (in case the HPs kick in during hte day) and only export the solar.

I’ll answer my own question- i got an email a day later saying i was now on octopus outgoing… now have to adjust my automations to not consume every last drop. 15p/export vs my night rate of 7.5p means worthwhile exporting once the battery and the hot water are complete.

Sorry to thread resurrect- but for you CoolEnergy owners- any way of getting the COP (or even just the actual heat output) out of the Controller? I have the electrical measured elsewhere but would love to know what COP I’m getting. Just not love it enough to pay £1000 to emonpi for their meter…

Yes it’s £150 back if they reject you, so only £100 lost, but just wondering what hoops I need to go through having had all the paperwork submitted to them already.

I have batteries (although set not to export due to the 3.68kW per phase limit) and on Octopus Go so 7p overnight 11.30 to 5.30am and 23p the rest of the time. Getting a blended rate of approx 16p so far this year. in winter with the HPs I rarely get past lunchtime before the batteries are flat. Let alone 4-7 to export what’s left. I charge EV, battery and dishwashers/ washing machines overnight to maximise night use and can avoid 90% of daytime usage which means I dump solar into hot water tank and anything else. I currently export almost nothing but I could heat the HW to 65 instead of maxing out the immersion and actually concentrate on some export.

Yep I do that already, but I have the capability to add significantly more PV (and DNO agreement to export 11.68kW) so I could be making money back on the days when I’ve filled the hot water tank, batteries and car. I can get 35kWh on a decent day with my currently 5kWp array. I have a functional smart meter so hoping for at least 15p/kWh. I already have the export MPAN from the DNO, just need octopus to accept it! I’m sure I read of others here who had used the non-MCS route?

Apologies for a new topic on this - I did search but couldn’t find previous topics- I’m trying to sign up for Octopus’ non-MCS export route. I’ve provided my DNO letter and Building Reg cert covering the install. They now want the £250 ‘with no guarantees’. Anyone that’s been through it know what happens next? Are there any further loopholes/ reasons for them to reject? TIA!

Looks significantly better than my roof! Fortunately I’m married to the SE and a quick site meeting was enough to decide to crack on without full replacement. I’d agree with the above- architect notes that existing load on roof being reduced and roof improved with breatheable materials.

I have a similar set up done slightly differently and nowhere near as neat. One question is- why separate the boiler and ASHP? Do they need to be hydraulically separate?

Generally it’s to keep all the potentially dodgy IOT devices and cameras in a network that can be tightly controlled and prevented from talking to the rest of the world. Then you can initiate traffic from your ‘main’ LAN into the IOT network to get the info but the stuff in the box can’t ‘phone home’. Lots of Shelly/ ESP devices used to be (are?) 2.4GHz only and didn’t play nicely on a mixed 2.4/5Ghz network.

You can choose the VLAN of each port on those individually? I keep my iot and camera network separate to the rest and have 3 of these in the network (mostly to save me getting up and pulling another cable 🙂 )

Yup beats my two ASHPS adding up to 42kWp. Looking forward to the floorplans. And how on earth you get that heat into the space. 🙂

I’m also considering this (and this company) but was going to install above the ceiling rather than create a bulkhead. My requirement is primarily heating but cool at high temp (above dew point) would take the edge off in summer. Use MDF to form plenums for the supply/ extract from the room. My experiments with various fan rads have shown that fan noise in bedrooms is totally unacceptable- even the motorised TRVs are annoying.. So the aim is to get this outside the rooms acoustically and potentially have some sort of baffle for the fan noise (which just adds complication and is the reason I haven’t progressed. Plan is to hang the FCU on catenaries to avoid vibration.

I’m sorry I can’t comment but I’m about to run into the same issue so watching with interest. I can’t see why a couple of holes in the trimmers would make a signifcant difference to the structures, but I’m no expert.

Thank you yet again for the depth of response. Sounds like I need to go get some professional advice rather than relying on your kindness to respond. The fixings at length do represent a significant risk which is where my builder is nervous.

CE’s MCS route worked well for me under the old RHI scheme- Friendly surveyor came out once I’d confirmed install and did the MCS cert and submitted. Job’s a good’un. Had a few foibles with my 3phase 18kW unit but mostly around the compressor terminals causing tripping issues. Fixed now with a new set of connectors recommended by Chris.

@sgt_woulds Another excellent and in-depth response, thank you again! Our Batman appears to be giving us the option of TLX or Bitumen and nothing else. So I suppose those are my options and he must consider it safe! Then it’s down to the insulation options I use- the builder has ‘allowed for’ his standard 75 over 75 between of PIR because that's what he does to meet regs. Nothing wrong with that on new build. I had specifically got planning to raise the roof lines so I could go warm roof, but without much more than a simplistic ‘warm roof will keep all moisture issues away’. Could I do your whole buildup on the outside of the rafters? Rafters, VCL, insulation, tlx, tiles? It would make some interesting details at roof intersections and gables, but I think that’s ok. Happy to discuss in PM if it’s easier to mention brand names/ buildups, will not take as pressure to buy 🙂

@sgt_woulds What an excellent and in-depth response, thank you. I take it the 35mm in your build up above is the wood fibre sarking board? The label appears to be missing. What stops condensation forming on the internal side of the felt membrane in your example above? This was an issue in my old loft when I pulled back the glass fibre insulation that had been stuffed between the rafters (badly)? I guess I need to understand the WUFI calculations properly. And my rafters are only 100mm to play with. Given the felt barrier, a cheaper way could be to use celotex over the rafters in place of the sarking boards- making the whole roof warmer? I’d happily have open rafters inside if it made things better! Sorry to answer with a whole raft of questions, I’m just fighting with the concept of mixing breatheable and non-breatheable materials on the roof and the horror stories you read on condensation. My only real references to TLX not being suitable are above in the thread, but I had read it elsewhere too. No recent or real worked experience, so if people are now happy that TLX isn’t murdering the flying squeakers, then all good and I’ll have to dip in for the expensive stuff! £16/m2 🤦

Frankly, I’d prefer the whole lot to be breathable- woodtherm or similar for insulation then a breather membrane over. My experience of bitumen felt is disintegrating membrane (both our previous house and this one) where it has become brittle and just breaks up.