TerryE

[My ital]. @DInwood you need to use the forum as a resource to get good benefit from it. If you find the right consultant and pay the appropriate ££ then you might get VFM. If you ask a complex and hard to read Q, then it will be discarded by many members as TL;DR, and other will reply on points. I suggest that you treat the forum more as a knowledge base and do your research; expect to invest time and effort in finding content that is relevant and learn from it. Forum search and Uncle Google are good friends here. The more karma you've earned in your content and responses, the more that old hands will be drawn to your topics. Focused and interesting Qs tend to get more valuable answers. I did my own near passive self-build roughly 2015-2017, and forum and community saved me a huge amount of grief, and we ended up with a far better living experience because of the advice given here, so I pay that back by visiting most days and contributing to interesting threads where I feel that I can add some value, if I am drawn to the thread in the first place. I also confess to getting tired of answering another variation of the same Q that has been asked and answered many times before. However, I have tried to documented my learnings and experience in my blog here and on various threads, so try reading these, and post any specific Qs related to these on the appropriate thread or topic, as keeping the discourse together helps other readers. I missed it if you mentioned your actual means of heating. For example my main heating mechanism is a water UFH embedded in a warm slab, with the average output flow temp to the slab loops when heating under 30°C. Most radiator based system use a circulation temperature of 60°C or more. The actual ASHP CoP achieved for these two regimes can differ by perhaps 2× at current temperatures. As @SteamyTea discusses, I heat my house using a very simple strategy: I dump enough heating into the fabric of the house during the 0-7AM off-peak to keep the average house temp stable, and accept the 1°C or so temperature ripple that I get over the day. I did design our heating system to use resistive heating in the first instance but facilitated the later addition of an ASHP. However I have never installed because I can't make the RoI case given out estimated savings in running / maintenance / depreciation costs. However if I did, then I would independently track input vs output power and feed this into my current heating control strategy: input power via power monitor on the ASHP spur; output by directly measuring flow rate and Δt of input vs return flow to ASHP. One of the issues that concerns me here is I don't want my own control to have to fight some smart ASHP control system doing its own thing. I have this huge buffer tank (a ~70 tonne concrete slab) which I want to dump a chunk of X kWh into, so I want to be able to turn on an ASHP with a roughly fixed output temp of say 32°C or capped power (< 4kW say) and turn it off when my control system has measured its output as X kWh. That's what I currently do with my restive heater, and it works well for me. Like Nick, I have been instrumenting everything over this last 5 years, and I update my control strategies from time to time based on that empirical knowledge.

I don't use any remote services for critical "always-on" stuff. And as for the idea of an IoT connected door lock or deep freeze -- 😱

What was your reasoning for this design decision? The estate agent that was selling our old house got chatting about our new-build plans and gave us an incredibly useful piece of advice: if you think that you might ever convert your loft then by far the cheapest option is to do this within your initial build. We had to change the pitch from 40° to 45°, but now my some has his own bedsit on the 2nd floor. It also simplified doing a lot of services. Whilst it is too late for you now, a similar argument applies: if you ever want a warm loft .... There is nothing wrong with having the MVHR on the upper floor, but running the ducting for the upper floor in the loft space; you just need to be very particular about how you insulate your cross-rafter runs. Alternatively you can opportunistically drop these into the warmspace, e.g. if you are using a double stud wall for stepped back-to-back walk-in closets then you might run them along the hidden ceiling, or if you can lose the extra 110mm or so headroom in a hallway, then run then in a false ceiling. This all being said, with a typical flow rate of ~ 1ms-1, the air will only spend seconds in this run of ducting, so heat losses with be negligible even with a 10cm insulation cover.

Any penetrations in your inner air-tightness barrier will compromise the integrity and need work to address. Eg. how are you hanging your joists? Sitting them on your inner blockwork leaf will involve a lot of taping to mitigate leak paths; joist hangers make this all a lot simpler. This is just one example: most air tightness issues are simplest addressed / mitigated by design before build rather than post-build repair.

I have ended up tolerating Google services: the are just too good and have no direct price/cost. Don't use Echo or Alexa through or any other always-on cloud based listening service. I refuse to use any IoT cloud-based service from any of these companies. Nearly all devices have an MQTT or equivalent transport layer that I can drive locally from Home Assistant.

Nick, the easiest way is not to bother. If you've got the Wemos or demo boards, then these can be powered through a miniUSB so any old USB plug can be used. When in light sleep, they only use 10s of mA so the cost is trivial. Not sure if a cheap powerbank will work with that trickle level, but that could be another alternative. Deep sleep in effect powers down everything apart from the RTC RAM, so you can still put a pulse counter in this and use deep sleep. The trick is to push the count using MQTT or equiv every 10 min or 0.1 mWh, say, and that way you only need to wake up Wifi and connect to your SSID on an occasional basis. As well as the Arduino Dev Framework, you could also use MicroPython or NodeMCU Lua to script this in a HLL.

Just another data point for @SteamyTea's table. ATM, the external temp is 0.3°C and falling and our daily ripple is about 1.3°C and we only heat the house in the off-peak window (midnight - 7AM). The temp peak varies slightly across the various rooms but a typical value in this cold spell is at around 11AM and the minimum at around 2AM, so the house drops a little under 0.1°C/hr. When the average outside temp was 6°C, the daily ripple was just under 1°C.

@pudding hasn't granted public access to the pictures. If he grants access to specific (google) users then the image tags will show correctly for those users. This isn't really a forum issue. If you link to stuff that is inaccessible, then it is inaccessible

AKAIK, option 2 is bad news from a blockage PoV you have a left 90° bend, followed by a right 45° followed by a right 90° all without rodding access. I can't see the BInsp being happy with this if he picks it up. This is a shit-show waiting to happen. Option 1 is a far cleaner roddable route. In general you need an accessible rodding access at any 90° bend.

? Uncle Google ? You can get laser levels cheaper these days. 😊

IMO you can't beat a Laser Level or even a good old Dumpy. We bought a Dumpy off eBay and sold it when done a couple of years later for a net loss of just over £50 IIRC. Worth every penny. Don't get two uptight about absolute elevation. We just used a nominal datum on the public footpath outside our driveway. All that the LPA care about is relative heights for the street scene.

CHP requires the infrastructure in place and if used can get an effect 15% - 20% conversion efficiency in terms of avoided energy costs. In general there is zero development here in the UK, so we are really talking about enterprise / business park level fit or retrofit.

Not all networks offer this as standard. See Which UK networks offer Wi-Fi Calling? In short you get what you pay for and the low cost offering typically exclude this. I have a sim-free Talkmobile deal which gives me effectively unlimited talk-time and texts and 15Gb data (usable in EU) but no Wifi calling at £7.50 PCM, so I am happy with this compromise: I use VoIP services such as WhatsApp for long calls, or take my mobile upstairs where I can get a good enough signal.

These have a major weakness IMO: If you need to temporarily unscrew the fixing then the back butterfly invariably drops down the back of the PB, so you need to insert another fixing. I would also personally avoid the Fischer self drilled type as overtightening can cause these to ream out a bloody great hole in the PB. I find the ballooning types such as this Fischer one and this Timco one for high load / vibration tolerant applications such as shelving.

@DavidFrancis I was just about to compose a reply to your 50% losses point, but I see that @pdf27 has already done a good response. The only reference to actual losses in the report you cite was on page 4 which mentions a specific 8% loss. Transmission losses are typically of the 10% ballpark because most of the transmission these days is done at 275kV and 400kV AC, with the subsea connectors using HVDC typically at 270kV. In terms of generation losses you need to divide sources into two categories: Those with use heat as an intermediate (eg. all fossil-based generation and nuclear). Here the physics of thermodynamics dominates efficiency constraints (see the WP article on the Carnot cycle) and this places a upper bound on the conversion efficiency, with the hotter the working fluid then the greater the efficiency. Those which use superheated steam as an intermediate can at best achieve 30-35% efficiency. The latest gas-based generators use superheated exhaust at ~600°C IIRC and can get over 60% efficiency. Those that do direct energy to electricity conversion (wind, solar, hydro). Take wind as an example: a conventional wind turbine can extract at most ½Kρπr2V3CP watts from a fluid stream where ρ is the density of the fluid (air), r the radius of the blades, V the wind velocity. The last CP is a dimensionless coefficient of power; there is a empirical limit to this known as the Betz Limit (~59%) because of the macro flow characteristics of the airstream around the turbines and modern designs can get within 80% of this, say a CP of 48%. The actual losses from mechanical to electric energy are tiny in comparison with a generator conversion efficiency typically ~99%. So overall conversion losses depend on your energy mix: oil/nuclear/wood pellet at ~30%; advanced gas at ~60%; wind at 99%. So adding in the 10% or so transmission losses then your 50% is a plausible ballpark for our current mix. Hope this helps.

You need two things to create a viable recycling industry: (i) volume, and (ii) time to develop it. An analog here: the Li battery sector; exactly the same claims were made, but this industry is slowly developing The main delay here is that the life of battery packs (with second use as grid scale and smaller fixed electricity storage) is proving to be ~ 5× longer than initial estimates, the actual volume is too small for anything other than pilot scale plants but some of these already have demonstrated ~95% recovery. So I do think that it is too soon to judge on this one. Even so let's balance this again the fossil fuel consumption over this ~20 year period, and of course all of the resources needs for its extraction, refining, and delivery to point of use. And the fossil fuel industry has its own challenges, e.g. Biden Administration Announces $1.15 Billion for States to Create Jobs Cleaning Up Orphaned Oil and Gas Wells.

In this last decade we've gone from under 20% to nearly 50% [1] zero-carbon electricity generation, and coal-based generation is now under 2%. It's a journey, not a quantum leap to 0%. See also this relevant talk by Tony Seba which is one of a series: The Great Transformation [Part 3] - The Disruption of Energy.

As I said above I have the equivalent if the Bright app running as a Node RED script and logging to my MySQL nodered database.

@Alan Ambrose, yup but you need to log out to be able to analyse it.

As I have posted elsewhere, we have a MBC TF house and are delighted with it. They are more expensive than some other TF suppliers, but when comparing them you really need to make sure what the scope of supply is. MBC offers a pretty complete package which includes many aspects that other TF suppliers exclude or cost as options.

We have a ~10 year old fridge freezer and a small top-up freezer in the utility, and a large larder fridge in the kitchen. We only commission the small freezer as and when we run out of capacity in the freeze half of the fridge freezer. The fridge freezer has the largest consumption of the three, but that's because it is old. We can't justify replacing it because it is cheaper to accept the slight inefficiency, than pay for a replacement. By way of comparison, our base load is around 150W, and this is for: 4×Asus mesh routers, 3 × RPi, 1 × Laptop; all at near idle. the 3 fridge / freezers when always closed the MVHR the slab circulation pump on a 10% duty cycle. So this is a few factors lower than your numbers. I am not sure why. This is an aggregate as measured by my Smart Meter and as billed by Ovo, rather than using a smart plug to estimate individual device use. My son's computer and TV kit when on adds around 70W on idle and 200W in use (most of the day 🤣). Opening and closing the chiller appliances, kettles and induction hob can easily add another 150 - 200W average during waking hours. Kettles and microwave are high load, short duration. Using the oven for cooking and baking causes a noticeable peak on measured use. We don't have a TV or media centre as we do all of our viewing on a tablet or Chromebook. All of our space and DHW heating, and machine washing are scheduled during the off-peak window.

The Great War poets are my favourite, though I have read a Larkin anthology decades ago. That's not the High Windows that I remember though the lines are familiar Larkin, so I looked it up: This Be The Verse. And nope, Direct Grant grammar school, then Cambridge, then the Royal Engineers before entering the real world. 🙂 My father similarly had an anathema to the use of face cloths that bordered on a phobia. We just wash ours regularly, say about once a week, and because we have multiple ones, that's probably after ½ doz uses. Yes they do harbour microbiota, but so I don't recommend sucking on one, but the moot issue is whether the stale oil and microbiota burden on the skin is reduced or increased by their use. PS. @revelation sorry for this wandering digression, but this sort of friendly interchange between the regular posters is what makes this a community and keeps us helping everyone. 😉

Our total energy actual use for this closing year is 10.9 MWh. All electric, green tariff. That's for a reasonably large detached house with 3 bedrooms (2 with en-suite) and a bathroom on the first floor and my son's bedsit on the 2nd floor. Total internal floorspace around 170m2, IIRC. We are retired so live in the house pretty much 24×7. Apart from heating, and normal whitegoods / cooking, the biggest chunk of our base-load is my son's gamer PC and his two 60+in screens. 🤣 As I said in my OP, adding an ASHP could drop this by up to 3mWh, but I can't make the RoI case when I crank the numbers. Food, booze, rates and electricity costs are about our only major outgoings, with no other maintenance or depreciation to speak of, because we designed the house with zero-maintenance in mind. Unlike the Willis which is a long life resistive heater, an ASHP has a typical life of perhaps 10 years, and well as needing annual maintenance.

Hot showers are far more economical (unless you do them @ToughButterCup style🤣). I am a little anal in my technique: I use about 5-10 ltr for a typical shower: a quick wet down; turn off shower and full body lather and rub down; leave lather on for at least 60 sec whilst flannelling; another wet down; flannel off any water and suds; a final slightly longer wet down, flannel off and towel down. Soap + 60sec contact + mechanical rubbing is better than an immersive soak (or just standing under a deluge shower) for getting rid of detritus, and surface bacteria and fungal spores. That being said, Jan took a tumble a couple of weeks back and she managed to crack a rib and tear some muscle and ligaments. Time is the only remedy for this type of fall. The pre-bedtime bath is better for getting a night's sleep during recovery. We've got a water softener and there's very little crap sticking the the bath. I find a quick rub down with a cleaning flanel gets it off.

I don't have a networking cupboard; just a 20cm deep shelf above my consumer unit and a flush mounted patch panel in the wall with a wall mounted ethernet switch below it. (This is in my utility room so having it all on view isn't really an issue.) I have a couple of Argon ONE M2 RPis (running Home assistant and a general Docker host) as well as my ASUS master router and BT 180Mb modem on the shelf. I also have 1 × Gb eNet to each room (a couple have 2 and in retrospect I should really have doubled these. I also have 3×ASUS mesh slaves (one in my study on the 1st floor, one in my son's bed-sit on the 2nd, and one in a shed covering the garden); these also act as local 4-port Gb hubs. I also have a PoE switch in the shed from which I run my external cameras.