Gill

A2A convert here. Currently very slowly renovating a bungalow in central belt. I spent an age trying to work out what would be best for space heating and DHW with the help of BH. You might find this thread has some useful information. TLDR : I decided my best option was dump solar to hot water. Heat pump water still not common enough so if it goes wrong it's potentially harder to get someone qualified to fix which likely comes at a cost.

I set on / off schedule for each day using the remote controls. Currently 2 programs in use Monday - Friday to put the heating on early morning and shuts it off before I head to work. This doesn't use the app. If I'm working at home, I just operate with remote control. If I'm in the office, I'll use the app to turn on the heating as I start my commute home as that isn't a fixed time.

I can't control away from home without Internet. Timers I've previously set using the remote continue to work as does normal remote control operation. It's a strangely disjointed system where the remote offers ability to set 4 schedules a day which must be stored on the unit. The app is simply hitting an api at times programmed into the app - if my router is offline (or mitsubishi cloud was down) it won't work.

My mitsubishi A2A system can be managed remotely. The models I went with have built in WiFi. I find the app clunky - setting timers relies on the app having Internet connection when timers are triggered. Handy for turning on when I'm commuting home or checking / changing temps but not for scheduling in my limited experience. Remote controls for each unit - didn't have any need for hardwired control panels . The unit itself does have thermostat and with high wall mounted, it's always reading a few degrees higher than floor level.

Thanks @PNAmble Will check that out. I also wanted to avoid phone attachment as I'm not convinced it'll be compatible with the inlaws Nokia3310. 😁

After a week of low temps and high humidity, some observations. Defrost cycles have increased. I've yet to spot one taking longer than 5 mins and more than two an hour. We we've been below 0 for a few days now (-2 consistent day temps). Energy use has spiked at a max 66kWh on the coldest day. Comparing to last years usage we were 85kWh over heavy cold spells and outside of that averaging daily winter use around 55. The living room unit is being over worked and takes time to get the room to temp. That was my downsizing in advance of heat loss improvement. Belive that is causing more defrost cycles. Still comfortable eventually and running constantly to avoid the room getting below 14 overnight seems to be working better. Our bedroom unit is on a separate outdoor unit. That room opens into our living area and having both units running seems optimal for warm air circulation. If I ever wanted to add another unit to our living area, I'd connect it to the outdoor unit that runs the bedrooms - that way it's unlikely to be on same defrost cycle. Overall happy with the last weeks 1st real performance test.

Is that frozen? Looks like candy floss but I'm assuming it's not.

I'd like to pick up one of these up for domestic use. I looked at hire which seems expensive unless you can condense to a single short hire. I think we'll have plenty of use for one over the next 6 months of renovation. Given resale value (at least for flir) seems decent it might be more cost effective to buy and sell on when we're done. Mostly will be used for trying to find heat loss areas (internal, attic, under suspended floor) and assess any improvement as we try to remidiate over time. Ease of use would be a plus as the inlaws also looking to get use. Any advise from folk who have used would be appreciated. Alternatives to flir or any brands /models to avoid? Thanks

Thanks- really useful to get a visual on it. I'll be keeping it in the back of my mind for summer if my garage conversion gets toasty.

Caveat - unhelpful post (somewhat). I have mitsubishi A2A linked up to MEL and that app is woeful. It reports my energy usage as 2kWh a day in winter which is lovely but very wrong. Short of 'on' and 'off' I have no confidence in it even when all component are mitsubishi. i hope it's just the AC system that suffers from this but I suspect it's not. I doubt it's playing nice with non integrated components. It doesn't even play nice with itself.

Also curious having discounted full A2a install in our garage convertion and now wondering if that was the right call. Thanks

That sounds like the defrost cycle. It should lead to water coming from the outdoor unit as the compressor is still running to defrost any ice build up. We're not planning a backup system although we did undersize our living room setup which may or may not turn out to be the correct decision. We wanted to avoid short cycling, we have plenty of heat loss issues to address along with some remodeling which hopefully reduces heat loss. If not we'll get another unit in our semi open plan living area. This is winter should give me a baseline to go from.

Yes. The indoor and outdoor fans stop until the cycle competes.

To some extent my smart meter data gives me a rough idea and comfort that the usage hasn't increased much at all with the temperature dips. Don't have a fixed heating schedule as routines are constantly changing. There was a channel on youtube did a decent dig into temperature vs energy consumption - Tim & Kat https://www.youtube.com/watch?v=mkSPS-scLMA if you're interested.

Hi @Ferdinand - I had A2A installed earlier this year. 4 indoor Mitsubishi LN models and 2 outdoor. In my limited experience, the operating temperature range was ridiculously hard to find for various manufacturers / models. Here's a doc link that covers my units : https://les.mitsubishielectric.gr/uploads/document/full-product-2022_air-conditioner_5045.pdf. Hidden in those 143 pages is the Guaranteed Operating Range range of -15 to + 24 for heating of my units. I recall looking into Daikin as well as a few other bigger names and only discarded them in favor of better COP /SCOP of the Mitsubishi models so I think most of the big players were in the similar operating range. Temperatures where I am in the last week have barely topped 10C and last few days we're not going above 2C daytime and dropping to -4C overnight. The units are heating the place nicely - noticed a few more defrost cycles last night but that's not had any adverse impact. Would be nice to find the time to rig up some energy monitoring to see how the drop in temperatures is impacting energy use but that's low down on a long todo list.

Thanks. The tank is sealed with the effluent piped to a drainage field in the field behind. Foundation loads I don't think pass through the tank. The nearest point of the tank is at least one meter from the garage side wall after the ground starts to slope a little downwards. One that I'll need to get the builder to verify though.

I've got an architect drawing up the plans and hopefully the builder will be out to see next week. When I mentioned the septic tank it was him thar noted it could cause problems so he's mindful of regs. Hopefully I'll know more about what can and can't be done in the coming weeks.

We bought our house with the septic tank as is so not meeting current legislation. The only thing our solicitor said we should get was confirmation of registration with Sepa. As @ProDavethread points out - that is (in Scotland) a tick box exercise. Thanks for the replies folk. I believe we need building warrant for change of purpose but whether BC need to be involved is one I'll need to find out. No change to height, location etc so hopefully that helps.

We are getting quotes for A2A system in at the moment and solar / battery. (battery is very minimal investment return if any but I'm willing to go there as I prefer to have the flexibility to use what we generate) Was nightmare to get started with A2A as few companies around central belt Scotland and a lot that are commercial only. Getting there slowly so hope to have a system in by July latest. The immersion we want replaced with unvented cylinder with multiple immersions. Solar should wipe out summer power use with divert to cylinder / battery. Winter we're looking to buy cheap rate and battery store to reduce cost of flipping all heating from cheap rate. Remains to be seen how this works out for us so we're keeping the storage heaters for the 1st winter. Happy to share the spec we went with. I have another thread that has some info on the quotes I've got so far here

I'm hoping to convert out stand alone garage to an office /granny flat with shower & toilet. We have an existing septic tank that is 1 meter away from the garage. I know it doesn't meet current regulations (5 meter rule) but it was installed 20 years back. Would latest regulation be applied if we need waste discharge from the garage? Or could it be applied regardless? Moving would be problematic as the soakaway isn't on our plot.

Just to come back on this - quote 2 in today at 9k. Quite a difference and included all electric work. The company did an on site visit and came across very knowledgeable. One more quote due next week before deciding but quote 2 much more inline with expectations.

Thanks. I appreciate there's more to it than meets the eye but looking at parts and install kit well under 6k mark means 6k + for install and overheads. I've another supplier coming Friday - maybe their quote will be inline and I'm miles away with expectation.

Anyone had any luck with A2A installers in the central belt? I've so far only managed to get one quote at 13k (ex VAT) for 2 x outdoor units and 4 x indoor units (2 x 1.8, 2 x 3.5) excluding electrical supply setup / isolator work. Looking at the unit costs on Orion, that seems like a very high cost for partial installation. One of my solar installers is FGAS registered but has only ever fitted water wet HP pump solutions. I'm assuming that like ASHP, you really want someone familiar with the intricacies of fitting A2A system. Any recommends out there?

Well that didn't go well. They want a g99 application from an installer that requests a 'budget quote' for a particular configuration. So I need to overspec a system before they will give any indication of what is possible.

The input from the other half which I've sanitised somewhat was 'I'd prefer if you didn't line the pockets of tesla'. That said, I do IT all day so it's not fun to spend the evening tweaking the tech. Can you turn off the mothership on the teslas? I'd read a while back about the. I intelligently deciding to charge ahead of potential storm that never happened. Can't be having my battery AI not comprehend I'd rather sit in the dark and be cold than consume peak rate electricity. I've not approached ours yet. That's tomorrows fun task.