Gill

Very much this. Im still waiting on two installers coming back with their recommend rig so maybe I'll get some additional ideas. The one national is very much pushing down the small setup /no g99 route. I've learned enough to know this isn't optimal for us. I'll admit I was put off by price. Draw rate is better than most. The greenlinx do seem good value with the drawback of needing the squirrel to boost concurrent output. There doesn't seem to be many options when you want higher draw. I think I need to do more reading as I honestly haven't looked at DC vs AC setup. More homework. I naively thought go with as much solar as I can afford to max out winter generation and size a battery for a winter store of eco 7 night rate to help reduce heating. (I get the battery isn't a financial Roi necessarily but will complement solar and our living pattern). Will over generate summer so export from panels and potentially battery could help payback. No performance degrade in the colder months? One installer was dead against outdoor battery install but I guess that could have been the battery they prefer to install - still waiting on those details.

Ah. My mistake - I thought the squirrel was performing the same job as inverter. So it's squirrels and inverters required. If you don't mind me asking, what inverter did you go with? I'll have a read through that thread - I want to avoid attic (summer heat) and indoor space is limited so at a premium.

Cheers for the data sheet. Nice stats - so your export always maxes out when you're not using. For your g99 was that based on your solar array max generation then instead of squirrel inverter? I did see they have a g99 datasheet so assumed like other inverters this was enforcing a limit. Does seem a bit odd. EPS not high on my requirements list. Would be a nice to have something but I can probably live with a extension cable in an emergency. Less of an issue with export not being limited. I've sent over a query anyway - good to know capacity should some random requirement come down the line. One other question on placement - temperature wise I'm thinking wall mount / get a rack under the house (suspended floor). That will keep the squirrels cool in the summer but there is a risk in depth of winter thar the battery performance will take a hit. Any experience with temps /performance? Thanks

@ThorfunThis is an interesting solution. I'm finding it rather difficult to compare batteries that meet my needs. Specifically in the winter months I want the option of a high draw rate as we'll be running some heating & cooking all on electric. If I understand the squirrel pods, these replace the single inverter? If I went two pods and enough batteries to max the draw, I have ability to pull 7 kWh concurrently. For grid export am I correct in thinking that would cap at 7kW also? How you finding the system is working for you? Also curious if it would support different batteries or if its limited to greenlinx. I'm not seeing it documented the max number that can be chained - how many pods are you running? The alternative I think would be a single larger inverter and batteries with high draw rate which only seems to be available on pricier models but there's a trade off - having more kit is potentially more points of failure. Never easy working this stuff out....

That's really good to know - thanks! We'll get applying for home energy scotland loan (6k battery / 6k solar) but once we get agreement the loan offer clock starts ticking and you've got 9 months. Interesting. I thought the inverter would limit all throughput. Does this setup require multiple inverters? Been having a read up on 3 phase which if I've followed correctly means we could export 3.68 on each phase without g99. Need to do a bit more reading but anyone able to confirm from this picture that it's three phase or not ? Or is this one i need to get a my spark to confirm?

Thanks @S2D2 I'll get onto Scottish Power. I'm hoping they can at least confirm if not feasible without having to make an application and wait for months. 7.36kW would be perfect. That would allow heating to draw from battery (assuming that I find a suitable battery to support that draw).

I've now had a few Installers out and one quote back. Given the advice to go big (and benifits from vat saving), I'm trying to wrap my head around the inverter piece /G99. One installer quoted for 5.2 kW system with giv 3.6kW inverter and 2x5.2kW giv batteries. Am I correct to think that 3.6 inverter means I could not use more than 3.6 KWh concurrently from either the battery or the panels? That would be very limiting in the winter months. They also mentioned a bigger sized system at 13.5kW was feasible and even 16kW if we used West facing roof as well. The advice was start with a small system and upgrade later as G99 could take 9 months. Anyone have any time lines on Scottish power g99 application? If G99 was rejected does that then limit me to 3.6 inverter or is there alternative configurations. It would seem crazy to upgrade later at higher cost. Lastly - does three phase come into the equation at all? I think we have three phase (eco 7) but need to work out how to confirm. Thanks

Thanks - I'll take a look at all options as I'm very much at the learning the lingo phase. Indoor housing vs outdoor, large capacity vs stackable, extensibility, draw rates, grid /solar charge rates, AC vs DC.... What can of worms have I cracked open this time?😁 No wonder it's difficult when everyone has very different and specific requirements.

In the process of getting PV quotes with and without battery. The installer today asked me to come back with some batteries that I think I'd be interested in. Trouble is I don't know what's good and what's not or what features I should be looking for. 🙄 I accept there no crystal ball so expect no ROI but in electric only property with no EV and eco 7 tarrif it will give us additional flexibility and allow us to use more of our generation. I would like at least 12 kWh battery and would prefer more winter we can go through 20 - 30 kWh on peak tarrif and charging some of that off peak will give additional offset against cost. How did you go about comparing batteries? Any good resources to share that compare charge /discharge rate, multiple batteries vs single and other key features ? The standard 'top 10 home battery' compilations are useless and rarely include more than the powerwall for higher capacity options. Thanks

The plan is go get as much as we can all at once with whatever applications are required. I'll hopefully have the 1st assessment back in a few days and I have a 2nd company out on Friday. Some basic numbers have me leaning towards battery assuming we could size it for at least 10 KWh. If done at the same time as the solar there's some benifits with Home Energy Scotland. I've read that some have slower charging and draw rates than others - any to avoid /give more consideration than others?

A2A is hopefully going to be our heating system if I ever find a responsive installer. Good point with the extra winter generation. Will be interesting to see what potential installers say about feasibility of using the stand alone garage as well as the smaller east facing space.

Can't say I've looked into EV as yet. I have a cheap run around citigo that probably has another 5 years in it with mileage so low it doesn't make sense to go EV. That said, the distance drive car probably not got more than a year or two on it. How do you think EV taxation may pan out in relation to PV generation? I'm keen to get the PV install right for future needs.

I'm just starting out getting PV installers out for assessment / estimates. Any lessons learned? Things you wish you'd taken into consideration? Financially, it's a no brainer as we have no gas supply in the area and a reasonable south facing roof with smaller West facing space. Additional smaller south roof on stand alone garage which I hope to convert to office. Divert to UVC will give me 7 kWh of storage. Summer generation more than we can use but down the line we'll no doubt go EV.

Id be happy enough rigging something up for myself. Was one of the negatives I keep seeing mentioned but it will still be a massive improvement on our E7 storage heating so I'm good with that. I'm hoping the other two companies I approached will come back to me as I'm feeling a bit like the non expert advising the experts. Hopefully that will change with an on premise assessment and further refinements.

Thanks @RichardL for your detailed response. The current plan isolates our cold front room from our warmer backrooms so should be good here. We will need to run that bedroom in warming mode (day) while lounge /sunroom could require cooling. Our main bedroom doesn't need to factor in as we'd only cool occasionally and late night /overnight when the second bedroom won't be needing input. Fuse box is in the hall. Separate circuit sounds sensible. Will investigate that. Good to know. Its a bit of a guessing game going from E7 to on demand. Floor units I had discounted due to positioning. I'll admit I like the aesthetic of high wall mounted and our "easy install" option puts a unit on the rear wall. If we went floor unit that would be replacing the fireplace which won't work. Possibly there are alternative duct routings through the suspended floor that open up different positioning ( might require a pump for extract if I understand correctly). More reading required on my part. The sunroom (uninsulated) gets quite hot but you are correct in that the heat can dissipate somewhat through the house. At this time of year on cold sunny days it provides a welcome free top up to the living room temps. Summer (if /when it comes to Glasgow) it gets hot in there. Last year it hit 36 with the velux open but that is rare . AC is more a luxury than a necessity so I'm not overly focused on getting excellent cooling in that room. Heating wise, over winter we only used it for Christmas day dinner. 2 x 2.4 kwh heaters kept it warm. Given the occasional use I'd be fine leaving a storage heater in there or using a panel heater as backup. Been looking at the Mitsubishi MSZ-LN range. Have downloaded the docs - Excellent advertised SCOP (whether that is accurate is anyone's guess). That range doesn't offer smaller models so will need to dig around. I've yet to find anywhere that makes it easy to compare. Orion is good but I've found their specs to differ from manufacturer. I'm hoping the other two installers come back to me. A big part of the problem is that (what little I know) I seem to know more than the installers which does not fill me with confidence!

I've been trying to work out A2A sizing as the one installer that's come back to me hasn't been able to come up with a workable solution with two outdoor units. I think it's entirely possible but my calculations are giving me lower requirements. I've had a read through this thread but would appreciate any input on my calculations so far. I've used a basic online calculator for BTU (it doesn't take window U value into account or underfloor insulation so it's possible our requirements are lower than the figures noted) Requirements 4 indoor units / preferably 2 outdoor Living room. Currently heated by 2 x 3.4 kWh storage heaters. Room size 105 m3. BTU 13586 / 3979w Bedroom. Rarely heated but 2kWh panel was sufficient over the winter. Room Size 40m3. BTU 4794 / 1404w Bedroom 2. Office room / spare bedroom. North facing room which gets very cold without heat. Room Size 36m3. BTU 4285 / 1255w SunRoom. Would benefit from some cooling in the summer months. Generally we do not use this room over winter but there will be the odd occasion (Christmas dinner) where we need to heat it. Room size 68m3. BTU 11517 / 3373w. The bedrooms I was thinking 1.5. The sundroom, 3.5 unit I think would be fine based on our use. The living room I'm unsure of as it does have an opening to the (unheated) kitchen but I thought 5kW unit would be sufficient. We are not planning to rip out the storage heating this year as will provide fallback if I get this all wrong. The installer was looking at 7kW in the sunroom, both bedrooms at 2kW and 6kW in the lounge. I did explain our use of the sunroom but I don't think that has been taken into account . Their rationale for 3 outdoor units is that putting additional units on a single external increases the refrigerant quantity into apparently unsafe levels. They've been back and forth with Daikin, Mitsubishi and Toshiba but doesn't seem to be getting clear answers so are recommending three outdoor unit as 9kW is going to be max capacity for one unit. I have to say I'm in the dark on this - I thought you just looked at the max capacity on the external and took concurrent usage into account. With my calcs we could put the sun room and the living room on one outdoor unit and the two bedrooms on another. With the house layout the living room would need to share with the sunroom otherwise we'd be looking at three outdoor units. I'm not sure how I should consider sizing the external units - do they perform better at particular loads? It's unlikely we'd be using both the sunroom and lounge room on full power for either heating or cooling. I was considering up sizing the external unit that will feed the two bedrooms in case we decide to put another unit in the hall. Would that have a detrimental impact on performance? Appreciate any input. Thanks * correction - bedroom unit on back wall beside outdoor unit

Do you happen to know if the app can group eco7 time period usage? The Scottish power app is hopeless for that. I can look at a specific day usage and work that out roughly but no where can I see daily / monthly split of each rate. Basic functionality for eco 7 tarrif users you'd think...

In a similar position with the one installer that has come back to me. 6 kW living room unit - that's probably on a par with our two large storage heaters Same for the sunroom which is currently only used when the temps are mild and any use of cooling would be moderate The bedrooms they propose using 2 kW units. They're suggesting 3 outdoor units as the highest capacity is 11 but that this may actually be an approximate and that it would be best to work to capacity of 9. Very confusing. I'm fairly sure I can drop the sun room to 3. I'd ideally like to drop the living room size for better efficiency but I'll need to revisit heat loss calculations I did before the triple glazing went in.

Thanks @JohnMo I certainly don't want to be triggering any built in system safety release. So with that info I could potentially set solar immersion to 75 and eco 7 set at the recommended lowest input to avoid any legionaries type nasties? Edit:I will be getting someone with far more clues than me to fit and configure the system and keep me from blowing a hole in my roof.

I consulted the BH hive mind on similar. Might be some useful info linked on that thread. The cheap karcher we got has done a solid enough job but at only a few months old, I don't think it's had enough to do for me to give it a solid recommend.

PV seems a no brainer. I'll admit I've done zero research on it partly because I need to work out if extend into the roof is financially feasible at some point and if so whether the current advice I've had about that doing a full reroof is our only option. One item off list.... Two more added on. 😁

@Iceverge thanks a ton for the input. I was converging on UVC ( and solar eventually - that's a whole different thread of questions !) but I 100% suffer from over analysis and this is a classic example. Stuck in a loop when the margins are so close. I'm going to chalk this one off the decision list and enjoy a glass of that nice wine.

Eco 7 tarrif at 0.44 day and 0.15 night. Occupancy of 2. I calculated we use 6 kWh daily for our current system. That may increase a little when we refit the bathroom to bring in a deep soaking tub but that'll be a luxury and not ever day use.

Will need to play around with that a bit as I'm not familiar with a lot of the solar terminology. Basic defaults for my location with roof pitch giving me this. Edit - looks like I can discount that due to lack of water capacity. Offered with a choice of domestic hot water storage capacities of either 90 liters or 120 liters Sometimes I think I should just flip a coin. I should probably add a factor of 'hours spent trying to comprehend viability and ROI' to each solution but I don't think I want to see those numbers quantified 😂

My washing machine is wifi enabled (not a factor in my purchase). Has never worked. Full manual control was a requirement otherwise I would have a very large paperweight in my kitchen. I would never want to rely on WiFi (and certainly not cloud! ) for critical home functions.