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Flir One for Android smartphones for £221 is the lowest cost thermal imager I know of. If you get one you'll find it incredibly handy for all sorts of things. I've been mapping out the location of my CH pipes as well as finding air leaks:

Speedfit 10mm ch pipe fits on my gun plus taping it with electrical tape to stop it forcing the pipe off as the foam flows. Only issue with the longer tube runs is the pressure needed on the gun. The foam does come out a bit differently too, at least with Soudal blue flexi airtight foam.

After working on the roof all week -3-8 It felt almost tropical today at +3

Think you may be missing the point of UFH, it doesn't need to feel warm. A radiator feel is hot, because its small surface area needs to be hot to transfer heat to the room. UFH area is the size of the room, to transfer the same amount of heat to the room it can be cool in comparison. In some cases almost the same temp as the air temp at the end of a heating cycle. Your bedroom on radiators benefit from heat transfer from the downstairs as well as getting heat from the radiators. The upstairs heating is being supplemented by the downstairs heat. Your downstairs is using 40kWh not for 2 hours heating, but really for 24 hrs, because its only on for those hours. You are really putting an average of 1.6kWh in to the floor when averaged out. Your upstairs has an average of 1.25kWh. So the same heat as a small electric convection heater for up and downstairs combined. Don't think that bad, looks quite good to me, its not a spring day, its been well cold outside. As I said two way to operate, long and slow or blast with heat, your doing the latter and as you have to run your boiler at the temp you do, its working ok for you.

Do you have any paperwork showing heat loss calculations and radiator output? If you had then you might be able to see if something has been done incorrectly

UFH running is down to how much insulation you have below the UFH pipes and how you operate. So 150mm is good so not down to that. Heating 10s of tonnes of concrete takes quite a bit of energy, so there are two fundamentally different ways to operate the heating regime. Throw a load of heat at it over 4 to 8 hour period, just like a storage heater, then let is trickle out. This is pretty much what you are doing. So it uses a bunch of kWh in a short period. Doing this wrong you can get thermostat overshoot, which is waste full and will use more energy. The other way is a gentle flow of heat into the floor, so heat in, matches heat out, the heating period is pretty much 24/7, this entails using a lower flow temp. If coupled with weather compensation this operation can be automated. Otherwise, it can be done with a little bit of fiddling manually with the UFH mixer. As a comparison our flow temps at -5 are about 30 degs - yours 45 degrees, ours is running 24/7. Either way will use a similar amount of kWh other a couple of days. If you can reduce boiler flow temp, there are small gains to be had, as you will be condensing more.

If you install the system around a flow temp of 30 at -7, so a well insulated UFH, there is no reason it should cost more to heat your house. A Media 6kW monobloc at -7 and 30 degree flow temp will give a CoP of 3.4. Gas boiler at low flow temps so a like for install should give a system efficiency of about 97% (that is what is currently running at). So a heating day uses 100kWh (nice round number) going in to the floor. Gas 100 / 0.98 =102 kWh Cost = 9.78p kWh = £9.97, plus standing charge of 27p = £10.24 Electric 100 /3.4 = 29.4 kWh Cost = 33.068p kWh = £9.72 So gas is slightly more expensive but pretty close But at 7 degrees instead of -7 the CoP goes up to 5 at the same flow temp, so costs reduce for electric by 32%, then gas wins by a good margin. A poor install costs you more (45 degree flow the CoP drops to 2.4, so cost 30% more to run). A good one can cost you less.

But how airtight are the carcasses for your units? They're usually made from flimsy stuff at the back dry slotted into rebates. Liberal application of Ilbruck FM330 (doesn't have to be pretty) along the wall/floor interface would be my plan.

The floor is unlikely to be much warmer than the room, so will feel cool to touch. If it was hot, your heat loss from the house would be higher. Ours is also cold to touch, but house is warm. We have a very similar house floor area, 192m2, but single storey, the ground floor area is 192m2, all vaulted ceilings and an outside surface area of 624m2, so twice as much area to leak heat. If on the coldest day your thermostat is clicking off, you could be flowing at too higher temp, that means there are gains to be had by reducing flow temp, which will increase CoP and use less kWh. Also review your domestic hot water flow temp and set point. Another thing to check especially if your flow temps are high or if you are close to capacity when in heating mode, do any immersions kick in, controlled by the heat pump? Your heat pump could be asking for them to work as well as the heat pump.

Thinking about how to revisit this job and I think I'll try a length of PVC tube on the end of the nozzle. Two man job - one to operate the gun the right way up and another reaching under the cupboards. When I say man...

Base boards off and can of expanding foam to pb/wall/floor junction? I did this in mine although I couldn't get access to it all. Gun didn't like being in the side on position much either. How quick can you get hold of compriband?

When I was installing our new dishwasher in the summer, I had the kick panels off under the sink unit and marvelled at the ~20mm ragged edge gap between screed and bottom edge of the dry lining. I was going to foam it but the gun had seized so made a mental note to come back and do it later. Yeah, right. Of course now I think about it the gun and canister wouldn't have fitted under there anyway. I can just imagine it.

You need to pull the kick boards off and reach under to seal the PB to the floor properly. At least it does not need to be done neatly as it will not be seen. Is there not proper air tight layer behind the plasterboard?

Is this to achieve more plasterboard to floor sealing? I ask because the way you put it sounds like you could mean sealing the top and bottom of the baseboard instead. This would obviously leave a large volume of unconditioned air under the units - the inside of which would also be cold.

The hot water is fine, it's heated the tank and the actual fan outside worked. I'm not completely convinced the heating is working. The stats are calling for heat but the actual heat pump fan isn't working outside 🤔 I'm waiting with baited breath to see if the floor gets warm and the temperature rises in the rooms but surely if the heating was working the fan should be working on the unit outside.

Short answer is yes, definitely worth it. My bungalow had a fair few holes in it when I first put MVHR in, as I was still in the process of doing each room and got fed up of seeing the box, and it made a huge difference even with the leaks, much dryer house and my energy usage has dropped year on year for that and beyond whilst I’ve done more work each year. For me it’s still the best thing I’ve done for this property

So excessive that 300 l cannot possibly be the correct volume.

Solved it!!!! That red handle - turned it for 20 seconds or so then put it back and it worked. Everything back working again. No idea what's it's purpose is or what it did but it worked.

If the manifold water is not hot enough to heat the house, turn the mixing valve up. Once you know what manifold temperature you need, then turn the water leaving temperature on the ASHP down to only slightly above the required manifold temperature.

No problem- new trap £4 so off to buy one. Z

That makes sense. Yes anything can go underground but it may not be cheap. A local self builder here had about a 200 metre run of 3 phase 10KV overhead buried and including his new connection for his house cost him in the region of £10K. It was a must for him as the line went right where the house was to be built.

I put one into my 1880s home. I figured air will take the path of least resistance so giving it a route in/out of vent ducts should still achieve most of what a MVHR system should.

For us, the demolition planning application went in at same time as the FPP (just a separate form), and was automatically approved at the same time.

don't forget to ensure your CIL exemption is signed off before commencing/demolishing! the last thing you want it to be hit with a massive bill for CIL.

Yes, completely different. You need a form from the council, fill it all in, you might need an asbestos survey and a method statement from demo company.

Turning the handle off should shut it off. If you don't want to tackle it yourself you just need a plumber that can follow that simple instruction, not a specialist heat pump plumber.

The next day. But have you got your consent to demolish, get that organised now as well then it will be current ready to knock down.

Doesn't the HW tank have an immersion heater as a backup? For heating you could get some cheap electric heaters.

The next day. The longest time limit depends on the LAs policy

No don't think so, enough other jobs to think about. MVHR is all sorted setup and running nice and quietly.

That shows you what the flow rate is when it’s running. It could be a relay in the Samsung controller box causing it. A neighbour had exactly the same issue which required a new PCB. In his case I powered the controller box off then on and the main circulating pump immediately started running which it shouldn’t do if there’s no call for heat. The relay in the controller box was stuck closed. I’m pretty sure there’s a diagnostic test you can do that manually turns the pumps on and off. If you turn it off and the pump still runs then it’s likely a fault in the controller box. Call Freedom Pumps as they are generally very helpful.

In Scotland, you have to submit full plans, there is no simple building notice option. Building control approve the plans before you can start and then their inspections are to determine it has been built according to the plans. If something changes, and they deem it important (I would expect such a massive change in the insulation spec to be so) they will insist on a new set of drawings to show the changes. As this is an extension, it might be being built under a building notice where it is everything agreed as you go. but as the client I would want to be involved in any discussions changing anything.

25mm???? Mate, you're going to be throwing heat away and you'll resent that extension for the rest of your days. The roof is the least of your worries. You need to get those walls sorted before you go any further. You mentioned 25mm insulated plasterboard. That won't do the job either. Can you get to the wall cavities at all? You'd want to remove the boards that have been put in and get the walls pumped with EPS beads. Either that or 75mm insulated board.

It is a FLIRone apro attached to my iPhone. Looks like I paid £320 for an open box one. New price is over £400. I didn’t really want to spend that much but it has been very useful.

My brother and his wife have a flat built in the 90s. They get mould on the walls I think because they close the trickle vents due to drafts and they haven’t replaced broken extractor fans. My parent’s last apartment had central extraction and she kept turning it off as she didn’t like the noise(which was barely perceivable). I could tell straight away from how stuffy it was when I went in. Their new place has MVHR and I have told her in no circumstances can she switch it off otherwise I guarantee she would. I also haven’t told her how to work it so she can’t mess around with it. This is why we have these regs.

Indeed. I will check but the thing that attracted me about it was that they monitor it remotely and, if the alarm goes off, they can attend the property and sort out the problem. I'd have to check whether that's really included but it's a bit of piece of mind if we go away. Other than that, yes, I can't see any great advantage to just doing it myself. I'm hoping that the AlertMaxx can connect to an app so that I can monitor it directly myself.

Your understanding is correct, at 1 degree outside your target flow temperature would be 40C with those settings. By implication your system was specified to operate at a maximum 45 C flow temperature and your heat pump and radiators were sized so that the heat output would meet the demand (i.e. the building rate of heat loss) when the outdoor temperature is -4 (with whatever spare capacity was deemed advisable).

One bit of psychology to add: once a big decision has been made, you're invested in it and won't give it a second thought. It's only at the umming and ahhing stage before the big decision has been made that your mind will be 'all over the place'. Crack on.

The idea would be: -Off peak rates are 1/4 of peak time on Octopus Go (or maybe even less - more like 1/5 for me) -If your heat pump has a COP of <4, it's cheaper to use the immersion off peak than to use the heat pump during peak time -Obviously during a time of year when you don't need heating, you just run the heat pump to heat up the hot water tank. But when it's cold enough the heat pump is working a significant portion of the day to keep the house warm, you could be better off running the heat pump on space heating for the entire off peak period, and simultaneously running the immersion to deliver hot water. The immersion is less efficient - but it's cheaper than running the heat pump for 2 off peak hours on hot water and then having to run the heat pump for 2 hours more during peak time. Only makes sense on Octopus Go like plans, though, where the off peak rate is so cheap it outweights the COP advantage of the heat pump. As you said, on a non-variable rate, you wouldn't use the immersion at all.

Had the meeting which was very reassuring. He answered all the questions and encouraged me to ask more anytime and will keep an eye on the builder. Fair play. A good soul.

I am not sure the installer is asking the question clearly. There is an optical communication port on most meters, is he talking about that? Or is he suggesting you don't need to install your own generation meter as he thinks the smart meter can do that function? It won't, it will register how much has been exported but not generation, so Iwould fit your own generation meter regardless.

I think it is illegal to tamper with a revenue meter, though they may have a connection that allows for this. It may use the smart meters wireless connection, but they are proving to be unreliable.

I have often thought something along those lines should be easy to do. Cars use a similar idea in the Mass Airflow Meter. I tried to make an ultrasound one. Never got it to work. https://hackaday.com/2013/08/21/ultrasonic-anemometer-for-an-absurdly-accurate-weather-station/ May have to revisit it sometime.

I made a crude windspeed monitor, using a couple of small temperature sensors and a resistor. The resistor is glued to one of the temp sensors, and left on, I think consuming 100mW continuously so that it warms up that temperature sensor a bit. How much it warms it up by, depends on the windspeed. I calibrated the response into m/s by comparing it to a nearby weatherstation. I wanted it so I could try and correlate home heating versus windspeed.... I haven't found a correlation at all. I did find one versus light level from a solar panel 🙂 Nb: we have an air tight house with MVHR, likely why windspeed didn't seem to matter. Maybe if I had infinite time I would plot these things out.

I remember our Jeremy Harris building his own weather compensation programming but ultimately dumped it fir a simple room stat. I like simple (less to go wrong). I run mine from a simple room stat with a small hysterisis mounted in the hallway, no zones but run the lounge at a slightly higher flow rate (as this is the room you tend to sit still in the most). The stat has timeing built in but never use it. House one temp 24/7. Works fir us.

Thank you, if only it was an extension - this is a new build!!! Builder keeps telling us the quality/workmanship is fine. We know it isn't, but we're not builders, so appreciate a second opinion! We are now thinking we may need to get a snagging inspector in to try and get these issues resolved.

I can beat that ! My in the ground soil pipe 110mm was filling up with 💩. So I rodded it to the next access chamber . What came out was a round head disc used on a rodding fixing !!!

Is this to divide it into a pair of semi's?

The 1 1/2" usually relates to the inside diameter of the pipe. Can't you bathe in the stream? 😂