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Tado seem to want to charge a subscription for their AI features. I've just got a Wiser system whose advanced features are entirely free (at least at the moment). Not had it long enough to recommend but suggest you at least look at it before comittiing. Screwfix are selling it at a discount right now (wish I'd seen it when I bought mine). https://www.screwfix.com/p/drayton-wiser-wireless-heating-1-channel-thermostat-control-kit-white/7785v

'Infrared' in this context is marketing nonsense. There is a point to exposed infrared emitters but you are going to bury these emitters underneath other surfaces so the infrared emission properties will be of the surface not this graphene nonsense. Any electric underfloor heating will be the same efficiency as these graphene ones and likely cost a lot less. Electric UFH mats are really cheap and theres no reason to pay more. Now, electric UFH is a pretty poor way to heat a space, especially if the floor and house isn't well insulated but if you are only installing it as a way to take the edge off cold tiles then its running costs should be manageable with the right controls (ie, timers to limit its use to short periods).

Impressive!

Would have thought you could load shift the hot water and bulk of heating, especially as you are targeting most usage during summer when heating less needed?

You've said stuff like this a few times and everytime I try to understand what you are getting at but I'm afriad I'm not really getting your point. In case it doesn't come across in the way I indend, the below is not having a go, just trying to understand your argument. The pipes buried in concrete (at least in low energy houses) are going to be able to cope with almost anything thrown at them and will last a very very long time.* A lot of what we discuss here is how to get the maximum efficiency out of a system and the theme here to achieve that is minimum controls, low water temperature, system on most of the time with weather compensation (a technology that has been standard in all heating systems in other countries for literally decades). Even if you add lots of fancy controls on top of the basic system, the fundamentals of the system are such that you should be able to remove those controls and still get a very functional system. Similarly, if the heat demand of the house increases then worst case you need to up the flow temperature in the pipes to compensate. Again, most of the designs talked about here for new builds are based on very low temperature heating. If you can output sufficient heat with the water in the pipes flowing at less than 30oC then if some cataclysimic climate change happened and suddenly we were all living in -20C then upping the temperature in the pipes to 40-45C should still be able to adequately heat the house. Obviously if people want to extend the house then any extension would need work, but thats no real difference to any other system. If you have a low and slow design the system shouldn't care too much where the walls are if they needed to be moved. I do think that any 'smart' stuff added to a house should always be removable while maintaining the basic function of the house. Maybe you lose convenience or a little efficiency, but things should still work. Again, in the vast majority of cases, the systems discussed here are of the type that could be removed without significantly reducing the basic function of the house. Therefore, it is easy to offer any future buyer of the property the option to have all smart systems removed before they complete any purchase. So these shouldn't have a negative impact on the price of the property. * Plastic pipes don't corrode and UFH systems should have much less metal in them overall reducing corrosion of other parts and build up of gunk. They can be flushed if there is a problem. Even in the unlikely event of the pipes developing a problem, retro fitting radiators or even electric heating to affected rooms would be unlikely to dramatically change the sale price of the house. I do see a concern about whether rafts can be relied on to last as long as traditional foundations, but this has nothing to do with UFH.

If you claimed a self-build CIL exemption for your build and move out before 3 years after completion you may become liable to pay CIL. It can be a lot of money so check this as well.

Lots of inverters (not all) come with a controllable relay output that can be used to signal things like excess energy available. Your Panasonic likely has an input that could be programmed to set a higher temperature when there is a signal present. So combining these two could likely do what you suggest without any extra geekiness. But still requires some set up and knowledge. Whether it’s worth doing vs doing the work to export and sell excess to the grid idk. A 3.6kw system with 5.6kw of panels should generate a decent amount of power that likely justifies the £250 charge to get export approval with Octopus (for a non MCS system).

A single inverter with two MPPTs will handle two strings with different condition (and importantly different voltages/number of panels).

The doc suggests a £2500 govt contribution to an overall £4500 cost so not free, just discounted. Bet their require MCS certification to do the install though so there goes your saving!

I don't think most people put anywhere near that much thought into their systems. We on this forum are not representative. I can see this happening, but not because the bulk of people have analysed the costs but through inertia. ie, "the boilers broken, lets just use the AC for now and decide what to do with the boiler later". They'll stick on the immersion for hot water and then forget about it.

Nothing in the doc that Simon posted suggests that the new A2A element requires removal or disabling of the old system. To me that seems like one of the biggest changes. In the end I suspect this change if stands as is likely means almost everyone just installs new A2A and uses the cooling but continues to use gas in winter (possibly less). Not sure how MCS will work with A2A stuff either. Most of the existing MCS contractor base is not f-gas and don't think there is much crossover to A/C installers.

Now show a modern equivalent mediteranian design. It will have large windows too (though also plenty of shading/overhangs most likely). Old houses has small windows because glass couldn't be manufactured in large sizes. Once large glazing panels became viable people everywhere wanted to use it with varying levels of solar gain mitigation, from brute force carbon intensive mechanical forms to passive approaches.

Interesting document. Firstly, want to make clear that my comments earlier are in relation to summer generation offsetting any additional cooling load caused by this policy change. I've not been thinking about winter generation at all though not sure that makes much difference for our conversation. Secondly, the document shows significant reductions up to 2030, which again aligns with my comments. Beyond that I'm surprised by their predictions but also note that they are basing their graphs on agreed plans. It's inevitable that more distant renewable projects haven't yet been approved as most renewable projects are relatively quick to implement. Nuclear being the only real long term projects that might show up for 2040 predictions at this time.

For voltage you want the string max voltage to be close to the inverter max voltage. That way you get startup to happen even in low light. If your startup voltage is too close to string voltage you will lose a lot of generation in lower light conditions. Up in scotland I'm guessing that is a very significant chunk of generation. The current spec you want to look at is short circuit current. The MPPT current can be exceeded as the MPPT won't draw more than it can handle. If you can supply more current you effectively cap generation once the current reachs the inverter limit. But this means you get more generation in less than ideal conditions with the trade off of limiting maximum generation.

Just had a quick google and first hit with displayed prices suprised me. Combination insulated shutter with fly screen, automatic operation, coming in at less than half the price of pure fly screens I've looked at before. Feel like I've misunderstood or misremembered something.

It's one of those things I'd like to see trialled. Certainly the behaviour of the previous governments (which in this case I think means civil servants rather than ministers) has been to distrust the population and assume that allowing them to install something that can cool will lead to them using the cooling feature and still falling back to the traditional gas system for heating. Personally, I'm not a fan of air based heating (or cooling) systems. I've never experienced one where I'm not disturbed by the noise when sleeping and I can see that pushing a lot of people to maybe install a system, use it partially but also keep relying on the quiet, hydronic, system much more than any government funded scheme would like. But I think it's worth trying, Americans tend to have air based systems and they don't generally see them as an issue.

Exactly, they are contracted to be on even if the power isn't needed. Changes are being made to eliminate the need for them in the not too distant future. 'Spinning Reserve' is a somewhat outdated concept. There is nothing to stop inverters from covering this function, the issue is that the software in inverters has been programmed to cut off if the grid gets out of spec rather than try to compensate (the grid didn't want to deal with the complexity and when renewables were new they didn't need to). Now we have more renewable generation and batteries on grid, inverter systems can take over this aspect of the grid. (of course with careful planning, testing and synchronisation).

They are talking within a string, not between strings in parallel. So they want to maintain each string at a similar voltage. Their document explains that the output voltage of panels doesn't vary that much by the amount of light, it's the current that moves more and that doesn't really matter. If the voltage of the two strings is mismatched then you will experience more loss. Electrically, the string with the higher voltage will dominate and less power will be drawn from the string with lower voltage (reducing yield). Significant shading of a panel will reduce voltage significantly, but the difference between direct and indirect light mostly appears in current generated.

But to be compliant they would need to be locked to it. Most of the other options are configurable by the installer. Select language from menu at install, etc. Manufacturers will do exactly as they have done with A2W heatpumps. Create a different SKU for the UK and add a huge markup. Every SKU adds a lot of cost even if they don't want to make extra money. You are allowed to have propane cylinders of I think up to 15kg inside a house, but are not allowed to install A2A systems with R290 (99% propane) if they contain more than 500g of refridgerant.

I'm pretty sure this is wrong. It is an manufacturer approved installation setup to install east + west facing panels in parallel so that the bulk of generation comes from the east in the morning and west in the afternoon. Current in parallel sums. https://www.fronius.com/~/downloads/Solar Energy/Technical Articles/SE_TA_Efficient_East_West_orientated_PV_systems_with_one_MPP_Tracker_EN.pdf

I don't have good data to hand to point to (don't have time to find it now) but the sources I was following were talking about how we were still burning a lot of gas during the summer, while also exporting a lot of excess. The gas was being burnt as a lot of renewables don't have grid forming/peaker capability. This is apparently being fixed by changing inverter programming and the deployment of more batteries (to replace a lot of peaker use). IIRC the expectation was that in 26/27 it would be a lot more possible to shutdown the gas plants rather than exporting excess. A lot more wind capacity is coming on-line over the next few years, same with solar. Even if opening BUS up to AC systems generates massive demand, I doubt the industry has enough capacity to install quantities of cooling over the next few years that would show up in national energy use stats. By the time it does a huge amount more wind/solar will come online. Thinking aloud, I wouldn't be surprised if easing deployment of A2A systems with cooling doesn't motivate a lot of people to install solar with A2A in a way that doesn't happen with A2W (without cooling). The economic case for solar to offset cooling energy use is extremely strong compared to solar to offset heating energy use.

Yeh, their media management has been terrible. They were supposed to be the sensible ones stopping the chaos of the previous years, but all this briefing and mind changing just makes them look incompetent.

Terrible idea. That just leads to UK specific models that cost twice as much as as the EU model for less features. We are not far away from not needing gas in summer months. Green power generation is not far away already, but the power lines to transport it are the bottleneck. That's being fixed so a lot of extra capacity will become available in the not too distant future so I don't see an issue with offering cooling. Plenty of older people could really benefit from it during heatwaves. Use building regs to limit building design to stop cooling being used as a first resort for heat management.

Saw an eFixx thing on this recently. The person they were talking to was talking about how important it is to match the connector manufacturer and crimp tool as while it should be a standard there are tolerance errors that have caused fires. I don't know how much to trust this as eFixx can be a bit of a sales thing for manufacturers pushing their product but definitely worth paying close attention to. MC4 connectors are a common cause of issues.

If 4000k works from dawn to dusk for you then yes that’s a cheaper alternative. I’m mostly a night owl too, but I think there is value in having a way to subtly wind down near bedtime and the older I get the more I realise how lighting impacts that. absolutely. Mismatched temperature lighting is awful. Bulbs is the difficult aspect. LED strips are cheap and easy to do as CCT but I’ve still not settled on the best way to do temp changing bulbs as I’d rather not have smart bulbs but smart controllers, dumb bulbs. After the last conversation we had on this topic here I’ve started considering buying non cct bulbs and gutting them to replace the LEDs with CCT ones and controlling them with a custom controller as mad as that sounds because I’ve not seen products that do what I want.