joth

Yeah, you are right that if it's lower humidity (and temperature) inside then the enthalpy exchanger should help. I was thinking of the case where it's (much) higher humidity inside than out, but that isn't what we have here today Funny you ask - I was literally looking at options immediately after posting here. I'd like you that starts (or resumes) operation after main power is cut and restored, so I could easily put it on a relay switch to control only running it when really needed (and ideally, during cheap energy window), but got bogged down as the cheaper units all seem to need a push-button press to start operation, or have their own smart/cloud/app integration that I really don't want. It's something I may yet do if I find a good option. Good news is connecting continuous drainage is easy in the plant room, so doesn't matter if it only has a small internal condensate pan. In the meantime, I've tweaked around my logic to allow the FCU flow temperature to drop a bit under the dew point if cooling load gets high, and let it drop much below dewpoint if the house starts to overheat. I figure a short(ish) period of condensation on all the pumps and valves is tolerable; it's long term dampness on them all I'm concerned about for causing corrosion and parts to fail. (In all cases the UFH flow is hard-limited to not go below dew point )

Dew point in our house normally sits around 15°C but in the current weather it's been slowly creeping up, just about to hit 20deg. There's a double whammy here: the very warm outside air is a able to hold more moisture, and as it is staying warm around the clock it is gradually is doing so, raising humidity of air coming in. The system is not able to keep up with the cooling demand (ironically largely due to the dew-point restriction on flow temps - I could get it super cold if I ran it blow 10°C) so the inside air temp is crawling up likewise increasing dew point. Behind it is another irony, that we were warned force-air heating from the FCUs [which are never actually used for heating in practice] causes the air to dry out so went with an Enthalpic heat exchanger to retain indoor moisture, which is now working against us in pushing that dew-point calc up making cooling mode less effective. If I ran the FCUs below dew point for a couple hours they will of course extract moisture from the air (sending it down the condensate drain) thereby reducing internal RHI, dropping dew point, and allowing the system as a whole to work more effectively once again while sticking above said dew point. Ho hum

For an a2a system, yes definitely. For a2w I'd recommend provisioning for it if it's not too difficult, but in practice I'd always run the water flow temperature above dew point so the condensate is not needed (and actually just creates a liability of drying out and creating bad smells)

Define "effective". If you leave then running long enough, and ideally predict very hot weather and "get ahead" by starting cooling before the house is already overheating, they're extremely effective. It's what I use, and would happily specify in any build I'm doing the controls for. (But, i know i can do the work to make the home automation keep on top of the cooling demand. You don't *need* automation for this, but it takes a bit more proactive user intervention. I can't rely on the occupier being so diligent, and they may also do stupid things like leave shading up and open the windows when the outside temperature is hotter than inside) If you're more into waiting until it's unbearable then smashing the A/C into max, you need a2a AC.

It depends a lot on location (installers in expensive property areas charge more - somewhat justifiably as they no doubt have higher living costs themselves) However I'd be very surprised if you pay someone to supply & install A2W, UFH, 5 FCUs (and a DHW tank right?) for less that 15k. Not in the south-east, for sure. When I tendered my reno (in 2019) my builder quoted 8k to install just one ducted FCU on its own - without any A2W or plumbing work! That was obviously a throwaway quote for work they didn't want to take on, but still... FCUs are still not much loved in this country. If you do non-ducted / wall mount fan radiator it's probably a bit less. A decent bit less if your installer prices it as just another radiator install. Cheaper to install, cheaper to run, or ... ? If self-installing it's almost certainly the cheapest way to get heating and effective cooling. I contracting out, too many variables to say Running costs - probably the cheapest option, considering reduced maintenance load vs 2 systems, and esp with the increased TOU shifting that UFH allows. I'd always say put the UFH in, if you're doing some sort of GF slab that would accept it. Even if not connected it gives so much future flexibility. Specifically, UFH in a well insulated slab is both ideal emitter for renewable heat sources (very low flow rate), but also doubles as a large heat battery (storage heater) so you can heat it up during cheap rate and coast through the peak period. A2A really can't do that .

Maybe of interest to some people here, that would like to be on modern TOU tariff but can't get a smart meter due to lack of DCC coverage https://www.ispreview.co.uk/index.php/2026/06/chameleon-tech-uses-home-broadband-to-solve-uk-smart-meter-connectivity-woes.htm Technically not that different to what the Octopus Mini has been doing for a few years, except it sends the data to the central DCC so is supplier independent. It will continue working when you change energy supplier. Sadly it also lacks the handy MQTT interface of the competitor Glow Display IHD+CAD. There are some fairly absurd consequences of all thise: 1/ Despite being electricity supplier agnostic, this will likely break when you change internet provider (due to this industry wide failing that for most people, changing ISP changes the WiFi access point and changes default credentials to that WiFi) 2/ A rural property might: - fail to get coverage of the national DCC (despite gov funding to build it and a big drive for smart meters) - fail to get wired internet (despite gov subsidies to rural areas, and building regs requirement to prepare the house to receive it) - fail to get terrestrial wireless 4/5G coverage => Ultimately have to fall back on a foreign owned and controlled satellite internet provider to connect their smart meters to the supplier. Lets talk again about critical infrastructure sovereignty.

I connected mine from softened water, because that's how @Jeremy Harris did his. (His reasons were to avoid cost of another descaler ,and it makes a better cup of tea, IIRC) After 5 years I've not had any issues with it. Ours is a combi tank so the main kitchen tap is all softened, and we have a dedicated hard water spigot next to it, mostly used for cold drinking water We're in a fairly hard water area - borderline for being within the safe guidelines for drinking the softened water. If I have four mugs of tea (1L water) it's about the same as one bag of crisps. If someone has a medically prescribed low-sodium diet then they should avoid it still.

It's relevant for any external pipework. I think this is more common in F-Gas installs as they tend to be retrofits (in domestic installs at least), and tends to be easier by running pipes all over the outside of the building. (Ugly for sure, but easier & cheaper). I expect retrofits to increasingly use a2a for this very reason. This is the key decision point. If you're happy to pay for it, then an a2a (i.e. some sort of refrigerant based) system is the only way to get the "arctic gale" of an aircon system. Whether you combine one system with UFH & DHW or do two systems (potentially one exhaust air for UFH & DHW) comes down to shopping about, supplier selection and what they are comfortable working with. Cost wise it's probably a wash (one complex system vs two more conventional ones). A a2w heat pump with FCUs is likely cheaper to install and can perform very well (comfort and cost wise) if setup correctly. And is much more DIY-able if that's your truck. But it will never give the same frozen air blast of a2a

If you ask OpenReach they'll tell you only they are allowed to move the master socket. That detail aside... I'd say what everyone else said. Wrap some electrical tape to insulate the wires from each other before pulling back out through the wall. Else if they short they'll spark rather worryingly.

I have a Texecom Premier system, professionally installed, and honestly I can't recommend it. It's hugely antiquated. I posted a short-list of my grumbles with it on the Loxone mailing list 5 years ago -I'll copy below for posterity... The key question is do you need a "Graded" alarm system? this is never financially worth it for "insurance premium savings", the monitor/support contract costs more than the savings. It's really only worth it if you have high value items that the insurer refuses to cover without a graded alarm. Or, you just want the highest level of system for peace of mind. A graded alarm allows for automatic police notification. I found that a waste of time, as the ARC would call me and my 2 other keyholders before doing police callout, and if anyone answers they would basically just say "your alarm is going off" and hang up, no information on what cause or support in figuring out if it's a false alarm. Which was oh so helpful when I was camping on a mountain in another country... So I've now terminated that contract and do my own self-monitored alarm (via Loxone, and a network of mutually supporting neighbours) which is cheaper and far stronger protection. If you DO need a graded alarm, I keep hearing AJAX.systems is the much more modern system, and uses cameras for much stronger confirmed alarms. (Texecom has a camera offering now but honestly I wouldn't touch it given my experiences) Still looking for some first-hand feedback from someone that's lived with AJAX for a few years and see if it lives up to the marketing.

The SolarEdge modbus interface is not great - presenting scalers as value + exponent in separate registers is inherently racy and can create large glitches in readings. I extensively hacked the Loxone integration to work around this -- basically read multiple registers in a single atomic 64-bit register read, then crack apart the words and recalculate the correct values. BUT it's still better than their very low frequency cloud API. What do you mean by At the moment still time based?

Seems like the research was published in January but a load of AI regurgitation has sprung up about it in the last few days. Original paper https://www.nature.com/articles/s41598-026-35389-6 Not sure, the reference "problematic" LEDs in the study were 3000K so it's already comparing incandescent vs warm white LED. Skimming the article all LED lights roll off at about 670nm but you need about 1000nm+ for the IR spectral component they talk about I've always felt the CTT [colour temperature tuning] is bit of a fad, especially in a domestic setting. But I can see a variant having a large benefit of having WW / IR dual channel emitters, and dynamically increase the amount of IR emitted based on various factors. e.g., more IR in winter when the inhabitants will have exposed to less of it naturally, and also when the loss of lighting efficiency is not so problematic as the IR is at least contributing to useful space-heating.

And down-sizing the ASHP to allow these long runs at a low deltaT without short cycling, isn't it? Our ASHP is way oversized so will bordering short cycle (5 min runtime, 10min period) when just cooling the slab to ~16deg. I'm still getting COP of 3.5-4. But it's powered from PV - if I could double the COP it would give me about 30p more SEG payments per day on these hottest days.

This is how I set mine up (6 years ago) on our ecodan, the problem is it's not just the FCU loop that needs condensation proofing but also the primary pipework that includes the filter, pump, sensors, divert valves etc. None of those devices are designed for being insulated, indeed there's a risk of pump burning out if you really did, and they gather condensation as easily as the pipework. Adding a second, much larger, FCU and keeping it at dew point is how I've used it for past 3 years.

Yeah by hot i mean "not cold", c.f. typical (historic) uk climate averages: 15-35°C is the ideal temperature range for LifePo4, which is much hotter than the uk average of 10°C