S2D2

A up - you stopped the job to take a picture of the imperfect edge. Turns out that's a shadow. B up - they seem to be stacked B up and who has the time to be flipping slabs over. But there appears to be some sort of seam I don't understand the purpose of - a way to get a clean break? Disclaimer: Never laid a slab in my life (may do soon) and stopped myself Googling it. For serious answers look elsewhere.

Which brand do you recommend for this and do they have a flow rate calculator to check if multiple oval runs are required? I'm about to install my system but running into issues with the drop to downstairs, the easiest route is down a partition wall with a rather inconvenient 72mm gap...

Next Drive was available for a short time for battery owners but the latest version reintroduced the requirement for an ev, no idea why. Octopus never asked for proof for Go but if they wanted to find users without, it wouldn't be too difficult from usage. Cosy is convenient and allows my small battery to cover heavy heat pump usage in the winter. I experimented with tweaking the heat pump but with just radiators decided it wasn't worth it and just the battery do the work, charging 3x per day. The only compromise is the higher cheap rate.

Eon next drive is good but I've stuck with Octopus Go because I use Cosy in the winter and can't be bothered switching supplier twice a year. I see Eon now have "Next Pumped" but that's only 8 hours cheap overnight (maybe, they dont show actual pricing online) so not a replacement for cosy with the 3 cheap periods. If your battery can get you through the rest of the day though, 6.7p on next drive is very attractive.

To be clear, I'm talking about bidirectional AC, where the pricey DC to AC inverter is in the car. The Zaptec Pro can be had for £800, a bit pricier than alternatives but cheaper than the AC to DC chargers like the Quasar. There's also no requirement to support islanding on cheaper models, it can just shut off if it loses grid connection like a standard inverter, islanding should be a premium add on and won't be supported on the octopus deal. I agree it has some way to go, but if every car supported bidirectional AC by default the decision would be much easier. My EV doesn't so I invested in an extra battery module for my hybrid inverter as it just makes more sense at the moment. I still use a granny charger as I dont want to invest in technology that's likely to become out of date immediately this year when bidirectional charging is readily available.

Seems like specific but inexpensive hardware is required so they were planning ahead with the Pro. MyEnergi also claim to be launching a bidirectional charger this year: https://support.myenergi.com/hc/en-gb/articles/15196766224273-Can-zappi-do-vehicle-to-grid-V2G

The Octopus deal is for a Zaptec Pro isn't it?

It sounded like Zaptec enabled V2G via a firmware update, is there specific hardware required for bidirectional AC or is it just some comms that other charger companies could add with a firmware update? The price of the charger indicates nothing fancy?

For the octopus deal its the car doing V2G afaik, nothing special about the charger. Octopus also control it, which is fair enough as the savings are passed on in the lease cost, but unsure if it would cover house load by design.

Thanks for clarifying, I had in my head that locked air could be an issue with the high pressure outlet, not sure why.

Can the straight nozzle on the upstand you mentioned in the linked thread cause issues with the trap as it seems to be eliminating that source of air intake or is there a distance to the T where that's no longer a consideration? Or do the bottle traps have their own? I fitted an anti-syphon u bend to and existing combination trap and it eliminated most, but not all, of the noise. I think even that was a recommendation of yours so thanks for the ongoing input!

Yes, but if you get a good surveyor they will let you oversize the rads to cover 150% of the heat loss (at design temp 50). Combine that with the fact they have to use MCS air changes rates and you can drop the flow temp from their design. Mine came out of heat punk at 42 based on their "design at 50".

I self installed an A2A unit a few years ago then had Octopus install a Daikin A2W in January. You could still choose at that point, check at the survey stage. Not that they should in a 4 year old house but dont let them install the 9-14kW version. 4-8kW are all the same just limited by software. It's personal preference but I vastly prefer A2W now I've had both, it also covers your hot water.

Mine was £2.2k after BUS from Octopus, 8 rads. About 8 man days of labour. Get some more quotes, many companies are openly overcharging because some people will pay it.

From memory not locally at the unit itself, but it integrates with the Tuya Smart platform which allows you to do remote control and off/on and mode of operation on an arbitrary weekly schedule. Oddly temperature is missing but it's possible I haven't added the correct integration. I was controlling it using a raspberry pi and the Python Tuya API, this is quite involved though as you have to get a local access key from the developer portal. This gave full control so allowed temperature and fan speed scheduling etc.