joth

Also the controller will allow a "away" / eco temperature to be set during the holiday that maintains some reasonable level (we do about 15), meaning the house still had plenty of heat for the MVHR to continue to recover throughout the holiday and on return.

Right , we're all saying the same thing slightly different ways. It's the sum of the peak AC power output of ALL grid tied inverters that matter. If they total over 3.68kW you need G99 or export limitation. It doesn't matter what is on the DC side of the inverters, i.e. size of panels, quantity of batteries or their peak DC output is irrelevant. so even if the panels and batteries can only output 1kW if they're on a 5kW inverter you'll need extra permission.

Are you sure? Mine recently renewed and overnight just went from 5p to 7.5p. the daytime rate more than doubled, but that makes Go+battery more valuable, not less. There's no limit to the kWh of battery you can connect to a grid tie system. G99 is for peak power, not storage capacity

Hi buddy! Welcome to the forum. Generally how these forums work is you describe the issue and people here will try and help. This way others can also benefit from the advice, and chip in if the conversation triggers more ideas. (The forum is explicitly not for professional trades people to canvas for work, so in theory you shouldn't get any offers to help out of bound....)

Do grid tied inverters cost that much more? For me, ignoring any export payment, the benefit of grid tie is not discontinuity when the battery runs out; a transfer switch is never instantaneous. Also it means (potentially) 100% of household can be powered from PV + solar in summer rather than having to segregate the house into 2 consumer units 1 of which can never get the benefit of PV. Also, I'd imagine the battery inverter is not instant response so I bet the lights dim when you put on the kettle when on it, but that's a minor niggle compared to the other issues.

There's another company getting in on the experiment, anyone can sign up, it's not tied to the energy supplier to the house. They say they're paying £3/kWh saved but can't find any definition of how the baseline is calculated that the savings are evaluated against. https://www.powerrewards.app/ Wonder how good they are at stopping one house signing up to multiple schemes simultaneously

About 100W when left on standby, give or take. Our bedroom does have an overnight overheating issue, and the only heat source is the two bodies in it. Having cats means we keep the door closed, and a nearby trainline means we keep the window closed, and MVHR really doesn't move much heat around. I've installed a fan coil the actively cools the room in summer (cold water from the ASHP), and assists in passively cooling it in winter by circulating air from the hallway and guest bedroom (generally the coldest room in the house). I guess at the moment we're now providing about 4kWh from body heat, vs about 8kWh from electrical gadgets and 10kWh of active heating out of the ASHP, per day. So not an insignificant contribution.

I'm confused how your 6.2kW of solar is connected up without having a G99. Note you can't have 3.6kW of solar and also 3.6kW battery inverter without approval. It's the sum of all inverters that must come to less than 3.6, not each one in isolation

Presumably with 6.2 kWp of solar PV installed a G99 approval has already been issued. What inverter is the PV connected to? Do they have a hybrid / DC coupled option? The solar X battery system mentioned is AC coupled so will definitely need more DNO permission to install that along side the PV, whatever size inverter it uses.

As a counterpoint , we had texecom elite system professionally installed in 2021, and I find it antiquated and unreliable. https://ajax.systems/ is a much more modern system, supports wired and wireless sensors and camera capture. Can be DIY or monitored install. Not used it myself but seen good reviews

Most interesting! It's an a2a and a2w all in one? https://argoclima.com/en/discover-iseries-system/ https://youtu.be/7qknr8RPXzE

Literally at the same time? So like a 4 pipe air to water heat pump? Sounds a good idea, I didn't know such a thing existed.

I think this is fair advice for a self builder, but here we're passing advice to a friend of a (not?) self builder, who are near retirement and don't have the wherewithal to come do their own research on this, so I'd be very doubtful of their odds vetting plumbers and electricians ability to perform a job they've never done before. Unless you're an enthusiast, the average consumer would be better purchasing from an experienced installer, ideally one that's registered with the manufacturer they install from.

I'm using a Loxone miniserver that I DIY installed. It would be overkill for just this use case but it runs a lot of the house systems and easy to have it manage heating too.

There's so many free variables both answers can easily be right in some situation. In an extremely well insulated home you only need a teeny tiny heat emitter, and so long as the ASHP can modulate down to supply it at a low temperature without short cycling, then yeah a single room could conceivably easily provide all the heat for the house. On a conventional/older home it's a completely different matter, where that room would have to be belting out heat to deal with all the losses everywhere else. But if the room it's in has sufficient drafts and losses it's moot as it's going to be blown out before ever going to have chance to raise the temperature on any other room. Many variables

I'm using a Loxone miniserver, but that's for everything in the house, it'd be overkill just for this one purpose.

This is one nice thing with the ubiquiti gear: you can create a 802.11b legacy network with advanced features disabled. This has kept a lot of old and basic and low bandwidth IoT devices working for me, such as Fitbit scales, petwalk catflap, tempest weather station, etc

Ty! I tried searching for such a thing a few times but my google-foo must be waning

This is the underlying technical handbook https://www.gov.scot/publications/building-standards-2017-domestic/3-environment/314-ventilation/ "CO2 monitoring equipment should be provided in the apartment expected to be the main or principal bedroom in a dwelling where infiltrating air rates are less than 15m3/hr/m2 @ 50 Pa." As an IETF era software engineer, to me "should" means an optional recommendation (vs "must" or "shall" for a mandatory directive), but thar entire document is consistently using "should" throughout despite being titled a mandatory regulation, so I take it I'm completely misreading it LOL Does anyone here actually have one installed and use it to make ventilation decisions?

Interesting! That looks like a guideline making a recommendation though, not a regulation mandating these are installed by law?

I think you mean Scottish regs mandate a CO detector (alarm), not a CO2 sensor? I.e monoxide not dioxide I'm not aware of any regs around CO2 levels. If there were, there'd be a plethora of devices and professional services on the market for measuring it and correcting it. Edit: looks like since June 2022 regulations mandate CO2 sensors in new office buildings, although so far there's only loose guidelines around what to do with the data they generate, not statutory law https://www.infogrid.io/blog/improvements-to-ventilation-and-indoor-air-quality-in-new-revisions-to-building-regulations-from-june-2022 There's a campaign in place to extend this to schools https://www.bbc.co.uk/news/education-58243238 It looks like largely this is all driven by measuring CO2 as a proxy for measuring the overall quality of airflow, as a post COVID viral transmission concerns, rather than concern for the risks from excessive CO2 in its own right. This is certainly driving (or, being driven by?) the increasing prevalence of low cost CO2 monitors and iot services, so only a matter of time (decade?) before regs start pushing this into homes

Yeah I read somewhere that SE production/consumption figures are mad if you charge it from grid at all. Certainly I see the sum of all my daily household usag (including any taken from the battery) *plus* the additional used to charge up the battery from grid as my daily consumption figure, so typically 10kWh more than the real figure. Good to know they're working on a fix. If you turn off the charge from grid profile and just put it on maximize self use, you'll see the app gives much better detailed view of how much is being self used each day.

As an example, a lot of my mains dimming channels I put through a custom function to map 1%-100% brightness output from the lighting controller to 30%-100% brightness at the DMX channel, or whatever the strike value is that causes it to come on, but keeping 0 passed though as 0 so that off really is off on the dimmer.

As an approximation, yes this is correct. The PWM at 50% means it spends 50% of its time turned off so the energy used per second is halved. Yes many ways to do this. Assuming the kids don't have access Loxone Config to reprogram everything in the house, you can easily put a limit, or an output scaling factor on each output channel.

yes! And most annoyingly, I even have multiple versions of that logging here already, 7 channels on emonpi and 3 pzem_004t on ESPHome. It was just lack of care with InfluxDB instances (call me BOFH), and repurposing things to other circuits thinking the MELCloud logging already had me covered at better fidelity (DHW vs cooling vs heating) that meant I didn't leave it on the ASHP consistently 😞