jack

Do they say how it's supposed to save money?

You're obviously way more knowledgeable than me, but my main point was just that there's more to frequency stability in modern and future grid systems than the rotating mass of turbine-based generators. I hadn't followed it after the initial launch, but the Tesla grid-tied battery in Adelaide I linked to above appears to have been a roaring success technical and financial success. Worth a read of the short Wikipedia article.

We have a Brink Excellent 400, which can run at up to 400m3/h. The regs say it should be run at (I think) 280m3/h, which is insane. I'd have to check, but I think we currently run it at 100m3/h, although it's been as low as 50m3/h without any apparent condensation issues.

Just learned that there's a name for power converters via which non-synchronous power sources supply power to the grid to support frequency stability: https://en.wikipedia.org/wiki/Synchronverter

Our pantry total is 12W, from memory. An hour with those lights on is 0.012 kWh, or about £0.0018 at £0.15/kWh. Leaving them on 50% of the time would cost less than £8 a year. If it costs £60 to supply and self-install a motion sensor, the payback cost is something like 7.5 years. I don't know how often a motion sensor needs replacing, but if it's every 10 years, it marginal whether it would ever pay back its costs. You also need to factor in energy consumption of the sensor, and the embodied energy of manufacture and disposal. Worse, I doubt the light is on for more than an hour a day though, so even ignoring replacement costs it's more like a multi-decade payback. This is the sort of maths that ends up applying to all those small rooms that you nip in and out of during the day: toilets, pantries, bathrooms, utility rooms. In the end, it's just difficult to make a financial case for it, so it comes down to whether you want to reduce your carbon usage to the absolute minimum, or consider motion sensors to be something that improves your life enough to pay for them.

If all you have providing power is turbines that spin at a highly controlled rate, there's an element of truth in this. But when you start bringing online significant numbers of power plants that can output AC at an arbitrary frequency (as is the case with all wind turbines, for example, given that they use power converters), the issue becomes less one of frequency stability, and more one of a lack of available power. The solution is to provide a deeper power reservoir from which to smooth brief transients. Pumped gravity-based hydro is one way of achieving this, although it isn't fast enough for very high-rate fluctuations. Grid-scale batteries are another that could well be a useful addition to the grid in the short to medium term. Smart grids using car batteries and grid-connected home batteries are almost certainly in the mix longer term, although the complete farce that is the smart meters roll-out to date suggests it's going to be a long time before we're capable of doing this properly.

Got our smart meter being installed by them in about a month, and will definitely be watching it carefully!

I'm sure it was just an oversight, but that list included the name of the company you work for. Please take care not to include this information.

I could be wrong, but I think that info came from a single poster (I believe I remember who, but won't say in case I'm wrong). I actually think it's more usual for the GSHP unit (the heat pump itself) to be placed outside the house. Since it doesn't need a high volume airflow like an ASHP, there's also nothing to stop it being enclosed in a relatively sound-insulated enclosure. I think the main issue for the low interest in GSHPs is relative cost. It costs to dig, then you need to buy loads of pipework, then you need to buy the anti-freeze that fills the pipes. The anti-freeze then needs to be replaced every few years, from memory, which adds more cost, along with the hassle of safe disposal of the old fluids. For all this cost an effort you get a slight improvement in COP relative to an ASHP. The additional costs of GSHP mean you'll probably never make up the higher installation and maintenance costs.

Congrats on the best introductory post I've seen in a while! I'd be really surprised if you can't slot in an identical motor from another manufacturer. It's surprising how much of the components these things share. I think I read something like 80% of the market uses exactly the same plastic heat exchanger, for example. If you still have the unit and are interested in following up on this, post some details in the MVHR sub-forum. I'd be surprised if someone can't help you with some clues about a potential replacement.

Definitely sounds like a mathematical problem - maybe the meter is double-listed against your account somehow? Odd that this could be possible though.

As with panel heaters, everything is carefully worded to be literally accurate while misleading the unskilled reader.

I assume that's the general idea, but the way they're selling it is very snake-oily. They're comparing the efficiency of stored water immersion heaters with on-demand microwave-based heating. They should be comparing it with instantaneous electric hot water heating. I suppose there could be opportunities to increase the efficiency of those devices, but they're selling this like it's a revolutionary energy and carbon saver, which is just plain horse5hit. Edited to add: some incidental efficiency gains aside, I just can't see how instantaneous electric heating is going to be price competitive with the gas it's replacing. Bear in mind that if it's instantaneous, you can't take advantage of cheap off-peak power.

From the FAQ on their website: The last paragraph sounds like it was written by an AI that was given a list of technical words and asked to assemble them into grammatically correct sentences. Edited to add: They may even find a way to let poor people invest:

For me, the best option is a combination of switch to turn on (and off, if you wish) and a presence sensor to keep the light on for as long as someone is in the room. I'm not a fan of lights coming on automatically - I don't want a light to come on if I go to the bathroom at night, for example.

My parents in law are like this. They like the house to feel bright, and they can afford the electricity, so they just leave the lights on without any consideration of wasting energy.

I have wiring for sensors in a lot of places but didn't get around to installing them during the build. Rough calculations suggest it would take a long time to pay back the cost of the sensor in most positions, so I haven't (yet) bothered.

Double-clicking my bedside light switch turns off all lights in the house and garage. I'd put this feature in the top three must-haves if I were to build again. I also have a dedicated switch at the base of the stairs that turns off all the upstairs lights. It's nice to be able to click it as I walk past on the way to the kitchen from my office! I've also put many of the lights on a timer, so they turn off automatically after a certain period. I think it's a couple of hours for the kids' rooms (I started with an hour, but there were complaints about the lights turning off too soon). It's half an hour for the pantry and the laundry, both of which my wife would leave on all day after using them for 30 seconds in the morning. None of this would be necessary if anyone but me knew how to switch off a light as they left the room. Still, I distinctly remember how bad I was at this even when I was in my 20s, so maybe there's hope for the kids yet, even if the wife is a lost cause.

Good lord, what a steaming pile of nonsense.

I came home on Christmas Eve a few years ago to find that every single light in the house was on. I mean that literally - every bathroom, toilet, hallway, bedroom etc light was blazing, with just my wife and two children at home (all of them downstairs in the kitchen). A recent tweak to my home automation programming lets me open my phone, click a single button on the app, and turn off every single light in the house except the living room where we watch TV. It gives me great pleasure.

We repeatedly tried to get people to work on day rates during our build, especially for larger and less predictable jobs, and the vast majority weren't interested. In one case, I suspect the guy underestimated the time it was going to take to put up our larch cladding, and it coloured the rest of our relationship with him (although I didn't realise this at the time).

Did they give you some sort of monitoring screen with the smart meter? Does that track things any differently to the app?

I don't know what the difference is, but the Flair 400 doesn't look the same as the Excellent 400. Is the Flair PH certified? Just the standard that comes with it - G4 I think? Not F7, anyway. We're on the suburban outskirts of a market town, so no particularly strong need for better filtration.

The Brink Excellent 400 units (and maybe others?) seem to be rebadged by a number of other companies: Wolf: https://database.passivehouse.com/en/components/details/ventilation_small/wolf-gmbh-cwl-400-excellent-0324vs03 Envirovent: https://www.envirovent.com/products/heat-recovery-ventilation-mvhr/energisava-400/ I'm sure there was another one, but I don't seem to be able to find it right now. We have a Brink Excellent 400 that's mostly worked well for over 5 years since installation. It's very quiet - I can't hear it when it's at its normal background levels, even standing beside the unit. The unit itself makes some noise on boost, but with the volume of air being shifted, I think that would be impossible to avoid. It remains quiet at the inlets and outlets. The one slight issue we've had is an odd leak in very cold damp conditions. It's only happened a handful of times in five years, but basically condensation from the heat exchanger seems to escape the internal drainage path and make its way into the gap between the insulation and the casing, a space which isn't drained. When enough of it builds up, it finds its way out of casing along a join at one of the corners. To their credit Brink sent out an engineer to fix it over three years after installation. They clearly knew about the issue, because the guy turned up with a solution very much along the lines of what I'd been considering doing myself. Unfortunately, I don't think his installation was that great, because it dripped again the following winter, and I found out the fix hadn't stayed put. I then did my own version (basically a strip of plastic wedged underneath the heat exchanger), and touch wood it's been okay since.

Based on context, I assume "openings".