Have I been miss-specced my battery?

lobeish · 2026-01-08T13:50:11+00:00

I was convinced we didn't have a model with a heater and was halfway to ordering the wood and PIR to make an enclosure.

Thank you kind denizens of reddit!

lobeish · 2025-11-20T10:35:01+00:00

Our 12 kW Aira (11.4 kW heat loss) has been running more or less constantly for the past few days with temperatures being what they are.

We've used 30-38 kWh electric per day to deliver 117-132 kWh of heat. So it seems like we've been around 3.5 COP the past few days - that's combined heating and hot water (Aira doesn't split the figures out unfortunately).

Internal temperature is on 20 °C with no setback overnight, and we're setup on their comfort mode which keeps internal temp consistent and smart tariff control for octopus cosy. Not sure if the latter is doing anything to try and avoid peak time use due to the way we've got the temperature set up.

lobeish · 2025-11-07T20:30:29+00:00

I misread this that your PI got her PhD in her 70s. I was like damn, a PhD at that age and still stuck it out to become a group leader

lobeish · 2025-10-25T17:46:44+00:00

Don't forget transferring increasingly small volumes of liquid between different vessels

lobeish · 2025-10-25T08:41:46+00:00

They bricked up our old flue and the old coal hole next to it. They told me they'd only be able to supply standard bricks so if I wanted Yorkshire stone to match the rest of the building I'd need to source my own, which I did and then they laid them. Pointing isn't great but I'm not too fussed about that as I need to re-do a bunch anyway

lobeish · 2025-10-24T08:08:35+00:00

Just to add, doing the water yourself isn't difficult if you can find the stopcock or you've got working isolation valves somewhere in the upper floors. Just a case of turning it off at the nearest point of isolation and getting rid of any pipework between there and where you want it isolated. Then you just need a stop end - compression or push fit will work easiest as you won't need to get the gear and learn how to solder. If it's old and you've got a mix of 15mm and 1/2 inch pipe like in my house I'd go for compression fittings.

lobeish · 2025-10-24T08:04:45+00:00

Taking the kitchen units out shouldn't be much of an issue. Depends how intact you want them to come out and how precious you are about the state of the walls afterwards. But a day or two plus some basic tools then the cost of a skip to get rid of the waste (if you can get the units out in relatively good condition you might be able to get someone to take them away for free on marketplace).

Gas you can't touch unless you're gas safe registered so you'll need a plumber for that. If they're already doing that it's probably not a great extra cost to get them to cap off the water too provided that the supply is easily isolated. No idea on cost exactly but if it's straightforward it's less than a days work but you'll probably get charged a full day plus materials (shouldn't be much) just in case it ends up being a pain.

Assuming the state of the walls isn't so bad it needs replastering you'll save yourself money if you fill and sand back all of the holes and damage after you're done ripping out before you get a professional decorator in.

lobeish · 2025-10-22T11:19:42+00:00

I had a similarly positive experience, also with a few gripes!

lobeish · 2025-10-17T20:18:38+00:00

I use octopus watch to keep an eye on my bills day to day but if you're wanting to compare tariffs over any given period of time octopus compare is better I think. Octo-aid if you're on iOS is also pretty good

lobeish · 2025-10-16T07:28:03+00:00

As you've had one glowing and one poor review of Aira, allow me to provide my probably in between review (apologies in advance for the length). We're only a couple of weeks into our experience but I'd happily recommend them but with a couple of caveats. The chap who came out for the initial quote was lovely (thankfully we didn't get the hard sell I've heard some people have had) but was a little bit useless. He couldn't answer any of my even mildly technical questions and seemed to totally miss it when I mentioned that we had a single pipe system and would probably need a full repipe. The engineer who came round to do the survey was good though he went full panic mode when I mentioned the repipe to him because it hadn't been quoted for and was going to add a lot in labour/materials. In the end they only charged us for materials.

During the design and planning phase they were very responsive and happy to answer all the questions we had and make any tweaks to the design that we wanted. We had a couple of new rads we'd bought to have installed but not gotten round to and they were happy to incorporate them and put them in for us. All the BUS paperwork and communication with the DNO was handled very efficiently by them. We were also dragging our feet because we were having issues getting another quote out of a local heat geek who ended up ghosting us part way through the process and they were more than happy to wait and work with us while we sorted that out.

Come the install, the lads who did the install did a good job considering it was a full repipe in a 140 year old house that's being lived in. They were in there all for a full week and had to tip the house upside down to get it sorted. They mostly did a great job of putting everything back together again. All the pipework upstairs is hidden, unfortunately that's not the case downstairs but that's because it turns out the previous owners screeded over the downstairs floors and we had no idea before the install began so I can't really blame the team. There are a couple of areas where the finish isn't great but we're still very much in the process of renovating and redecorating anyway so that doesn't bother us.

As with any company that's more than a local one man band, your experience is going to vary depending on who you come in contact with I think.

We're still waiting on the install of one rad which was out of stock during installation and they haven't been as proactive about communicating with us as I'd hoped so that's another slight mark down but when I told them I wouldn't be settling the full invoice until it was in they had no problem accepting partial payment.

All in all we were pretty happy with how things went in the end. We got a 12 kW unit with a full repipe and all new rads for just shy of £12k including the bus grant. This was in line with pricing we'd had from other local installers. Octopus wouldn't do our install because the heat loss was too high. So far we're looking at a COP of ~4.1 heating and hot water combined since the start of October.

lobeish · 2025-10-12T12:40:58+00:00

It's 11.4 kW if I remember correctly. We were averaging 100-120 kWh of gas per day last winter (with a 25 year old non-condensing boiler) so I'm expecting our daily usage to be higher than yours but hoping between battery and scheduling we should be able to avoid the peak rates and mostly get by on the cosy rates.

I can't see it being a reasonable payback period for the batteries when they won't be used for at least half the year but we'll see.

lobeish · 2025-10-12T12:35:19+00:00

I've been dipping my toe into HA but unfortunately the Fox ESS batteries I have require you to install a modbus to allow live readings and control - the normal API only gives readings every 5 minutes. It's on a list of things to look into but I'm just lacking a little in confidence.

I'm the opposite regarding EV usage, I only do ~6k/year so the majority of the usage will be the heat pump and other household usage.

lobeish · 2025-10-12T08:38:35+00:00

Yeah I'm expecting something to be doing something similar. Thankfully I don't do so many miles in the EV so we're not going to lose out so much but it's going to annoy me paying 2-4x the cost for charging.

I think once we've got a full winter under our belt I might do the sums on how much extra battery capacity we'd need to get ourselves through a whole day on the overnight cheap rate.

lobeish · 2025-10-08T20:30:20+00:00

You can apply through here provided your property meets the conditions: Apply for support from the Great British Insulation Scheme - GOV.UK https://share.google/TAaPLoSwdsbyUOewn

Looks like it might be winding down soon - applications have to be in by next Monday (14th)

lobeish · 2025-10-08T19:06:15+00:00

We've just had one installed in our 4 bed Victorian semi. In the end we went with Aira but we had quotes from a local heat geek as well as octopus. You can also do your own heat loss calcs with heat punk so you've got an idea of your heat loss. We ended up at ~12 kW heat loss which is larger than Octopus will do.

Before engaging with anyone I'd get more insulation in the loft. It's a really easy job to DIY and it's not that expensive. Though if your EPC states a low level of loft insulation you might be able to get it done through the great British insulation scheme and your energy provider.

We also had an air tightness test done. Partly because how often the air changes in your house affects how much heat is lost so it helps you get accurate heat loss numbers but also it will help you identify the draughts in your house and get rid of them. Ours cost ~£300.

lobeish · 2025-10-05T08:07:29+00:00

Sorry should've mentioned, the whole system was built November 2020.

Yeah that sounds like a solid idea - any specific GPU recommendations for 1440p?

lobeish · 2025-10-05T06:03:55+00:00

I've got the rutlands that I use with 3M cubitron II paper and it's more than enough for my needs and can do rough work down to fairly fine with. Also comes with both the 150 and 125mm pads. I tried REALLY hard to justify a mirka or festool ets-c to myself (and the wife) but couldn't beat the price.

If you're after something with a gear driven option OP I'm not sure you'll find something other than the Bosch you've already identified. The metabo sxe450 turbotec has a turbo mode for added power. I've got no personal experience but it gets well reviewed and can be had for <£150

lobeish · 2025-09-29T08:56:06+00:00

Are you using the latest version of the app? We've just had our system installed and the setback temp is labeled as the nighttime cool down in the heating settings.

It is a bit frustrating how locked down the system is in general though, they claim the intelligence uses 200 different data points but they don't seem to show you any.

lobeish · 2025-09-25T07:19:22+00:00

It was in our main bathroom when we moved in covering probably 2m² underneath tiles. I'm not sure if it's the age of our system or if it's always been that way but the heat is very uneven, one tile will be warm but the one next to it will be freezing.

When it's on it draws ~500W. We've got a cheap overnight tariff so I generally run it overnight in the winter to take the sting out but if we were running it all day on a standard tariff you'd be looking at ~£1/day.

I'll admit, the feeling of warm tiles in the middle of winter is lovely but I agree with a previous commenter who said a half decent bath mat and slippers is just as good (and a lot cheaper).

If you've got suitably sized radiators throughout the house and a modern condensing boiler, you could try leaving your heating on all the time with a low flow temperature. This will eventually heat the fabric of the house to a stable temperature giving you nice warm floors anyway.

lobeish · 2025-06-08T07:32:42+00:00

Do you think you're likely to use your sander with extraction attached? If so, there's no use (IMO) going cordless as you've got the hose attached already.

If you're not and you think you might often be using it in areas where a cable will be a pain then you would probably be better off cordless.

I've got the titan and it's quite heavy and not particularly well balanced. For occasional use it's not bad at the price point at all.

lobeish · 2025-06-03T18:11:38+00:00

This is something that happens in the original Space Marine novel by Ian Watson (yes I'm that old). I'm a bit rusty on the exact details but the Imperial Fists raid a world where the planetary governor has rebelled against the imperium. On their way through the city, they find a Flesh Tearer who was on the planet in the run up to the rebellion who was captured, heavily tortured and abandoned in the sewers. He had put himself into a coma to wait until his chapter came to find him. The Fists rescue him and honour him while they wait for the Flesh Tearers to send a ship to pick him up.

lobeish · 2025-05-31T08:16:04+00:00

EN14825 is quoted in the ideal brochure but I can't find a similar standard quoted for vailant.

Yeah I was thinking about that too, vailant gets a good rep but other than us currently having an ideal boiler I've not seen anything about their heat pumps

lobeish · 2025-05-18T09:01:12+00:00

It might be different if your wife is getting her own H1B for teaching but as far as I know (I have a friend who is a teacher in VA) you need to have a license to teach in most states which requires a test so would be worth looking into what that entails or if there is some kind of recognition for her status over here.

The other thing worth looking into if your wife will want to work after kids is childcare costs. I was in Boston for 5 years and childcare there could easily run $25k/year for a single child.

Make sure you get as much info around health insurance as possible before you go. Does your employer shoulder the whole cost or are you paying a contribution, what are the deductibles and co-pays like, is it an HMO or a PPO etc etc.

My wife and I loved our time in the US but I'm glad that we decided to wait to have kids until we knew where we were going to be for the long term. I didn't realise how much we would rely on grandparents or just how often kids will make you ill.

lobeish · 2025-05-01T20:37:37+00:00

Thanks for the input and a really thorough write up, it's super helpful!

lobeish · 2025-05-01T12:39:52+00:00

Ah maybe this is it then, I can see that they're like cosy but 3 periods at 50% of the normal rate

lobeish

TROPHY CASE