DamonHD

FWIW hl.co.uk does an Active Savings thing that puts everything in one place to reduce admin, and has enough participants at the moment that you can spread over several separate banking licences.

The last time I bought a VA replacement part it was not from VA directly since they wouldn't talk to me as an end user. I used https://www.uk-spares.com/ Rgds Damon

Should someone even be trying to heat a large conservatory in the depths of a severe winter beyond frost protection? Rgds Damon

I think that we count as lowish water users. The Thermino covers 1 x bath and 1 x shower comfortably. (~4kWh and ~2kWh). Write up on whole system in tedious detail! https://www.earth.org.uk/note-on-solar-DHW-for-16WW-UniQ-and-PV-diversion.html Rgds Damon

For us the Thermino 150 (~7kWh) seems to have worked out about perfect in terms of DHW availabilty and physical size. (3 bedoom London home: 2 adults + 2 teens.) I have just today turned off the gas combi entirely (as a test, for at least a week or so) and do not expect to hear any shrieks from unexpected cold showers. Rgds Damon

Hi, Not sure that I have any of that wisdom stuff to dispense, and I am in the middle of preparing for a meeting, but here is some of my write-up which may be useful (follow the "See also" links in the sidebar): https://www.earth.org.uk/note-on-Spacetherm-aerogel-thermal-insulation.html Rgds Damon

This thread is amazing, thanks @JamesPa and everyone else! FWIW I came across this rather good paper: https://www.gov.uk/government/publications/cost-optimal-domestic-electrification-code which talks about total cost of ownership of various electrified alternatives to gas heating, ie including the CAPEX and OPEX. Rgds Damon PS. I have an ulterior motive to be following this thread: I have started research to try to make this decarbonisation of heat (for UK homes already standing) work as well as possible: https://www.earth.org.uk/PhD-research.html

At our ~100W typical peak overnight load the Enphase covers ~95% of it (actually it overshoots a little to compensate and then rows back). When the fridge isn't running and we only have ~20W of other 'vampire'/residual loads, the Enphase covers ~75%. With the UK 500W-minimum unit, none of those loads would be covered at all. Rgds Damon

The Enphase seems to have a threshold of about 5W in either direction before stepping in (if it can, ie when not full/empty). When I asked the tech director of the next best brand at the time he said that theirs was about 30W. One UK manufacturer's director that I spoke to said their unit was 500W minimum to intervene, though he did at least listen to my observation that my night load peaked at ~100W including the fridge, and our day load would rarely hit 500W, so their unit would not actually be much use to us! OTOH, the *peak* charge/discharge rate of my system is ~1kW, so it does not fully cover the peaky things such as the dishwasher or the oven, so I prefer to run the former when the sun is out or in the dead of night when grid demand is low. Rgds Damon PS. Saga starts here: https://www.earth.org.uk/Enphase-AC-Battery-REVIEW.html

I may be misunderstanding, but I do get to essentially 0 imports on some days, eg when we are away or have no large loads outside sunny times. Look at the data under here for example: https://www.earth.org.uk/energy-series-dataset.html#V-imp Partly I picked the Enphase ACB system to have very low import/export threshold before stepping in. Rgds Damon

https://heatpumpmonitor.org/

Has the heater relay simply failed open/off? Rgds Damon

Here's a couple that I am using: https://www.earth.org.uk/MHRV-mechanical-heat-recovery-ventilation.html https://www.earth.org.uk/MHRV-Vent-Axia-Lo-Carbon-Tempra-P-REVIEW.html Yes, I think they do their job. Yes, I also see condensation dripping outside from the bathroom MHRV. Rgds Damon

FWIW, the boiler was fixed and then given a thorough service: https://www.earth.org.uk/note-on-combi-replacement-dilemma.html#2022-10-04 And should it actually pack in, sensible boiler man tells me that second-hand condensing boilers can be had for £200 or so. Rgds Damon

It should help. Rgds Damon

There's unlikely to be enough potential solar gain in winter to be significant: the insulation value of an extra layer of material probably outweighs it. Rgds Damon

I have used aerogel to good effect in my own home, in several varieties: https://www.earth.org.uk/note-on-Spacetherm-aerogel-thermal-insulation.html Blinds are unlikely IMHO to be air-tight enough to be much good to retain heat. To keep sun/heat out: https://www.earth.org.uk/towards-a-LZC-home.html#reflblinds Rgds Damon

About the same as an extra pane of glass. And if that window gets direct sun in summer, have reflective liners to minimise the risk of overheating then also. Rgds Damon

Indeed. Good to have what looks like a resolution LONG before we need space-heat! Rgds Damon

Thanks again for all the suggestions and discussion. C/o The Heating Hub today Tom Plumb London visited, and revived my existing expansion vessel at least temporarily. I've asked him (Tom) to come back in a couple of months and do a full service and replace the ev then if it looks like it's not holding up. But ... he's also a condensing combi and ASHP man, so we discussed those options if this Potterton packs in. He has seen the layout of the boiler area and house, and he's happy that something can be made to work. Rgds Damon

So harsh! I'll post any update here. Rgds Damon

Whatever is done will be by a grown-up eg GasSafe engineer. Rgds Damon

It's a Potterton Performa 24. Rgds Damon

For a while now the pressure reported by the combi has been swinging between 0 and 3 bar. When it gets low I gently top it up, but I suspect a failed expansion vessel. Rgds Damon

(We genuinely did have ice inside my bedroom windows until my dad did some DIY secondary glazing!)