SteamyTea

Can't really be answered. Like saying what is an average house, 60, 120, 180 m2, 1, 2, 3, 4, 5 bedrooms, 1, 2 3 bathrooms, but only one actual bath. Really comes down to discarding the cost of the common components i.e. cylinders, radiators, UFH pipe, then comparing gas, oil, and ASHP units that, and this is important, deliver the correct output. That rated output may be different for the different technologies.

This is really what this thread is about. I say that correctly designed systems work perfectly fine. Badly designed systems will not work as expected. There is also a slight difference in how they are opperated. In the past we had basic boilers and controlled the output with a combination of on/off temperature control, and a timer. This was because 'gas was expensive' in the days of town gas. Natural or North Sea gas changed this, and technology/legislation moved on, so now we have quite sophisticated modulating and condensing gas boilers, with temperature control in each room. Coupled to that the controllers can also adjust each room to have a different temperature, at different times, and different days of the week. This can also be done without machine learning, saves RTFM. But at the heart of any heating system is a machine that raises temperature and transfers it to a transfer medium, usually water. This is what the sizing is so important, and like cars, you cannot always gauge the performance on engine power alone. My bosses car is about the same power as mine, but faster. How can that be. Well it is three quarters of the mass, has a lower drag coefficient, and is petrol. But my car does more miles to the gallon (not the best way to work out efficiency, should really be kJ/km), is quieter and more comfortable. And cheaper.

This is a very hard one to generalise. Mainly because houses are different, and the occupants live differently. It does not change the underlying physics. Another problem is 'what does a heat pump cost'. Some people play top dollar, others buy off eBay.

Just looked it up on Google Earth, seems to be the place.

She lives in Whitchurch. She took me to a pub by a lock a couple of years back. Can't remember the name. Had a large carpark other side of the canal. But that is not unusual for canalside places.

The efficiency is not set by the type of building, it is set by the load cycle. So the question is wrong really.

Next time I am up seeing my best mate, I shall have a wander along the canal and have a peak at your place.

Was a tenner, but after I ordered hound them cheaper. They also do DC activated ones, could be useful for PV 'suff' i.e. diverting power. https://www.ebay.co.uk/itm/SelfSupply-Adjustable-Normally-CloseAC-Current-Sensing-Switch-SZC25-NC-AL-CH/114352241908 I got it to turn a fan on so that I can put my new oven under my induction hob.

Why not find another smaller one, then plumb that in for upstairs and the DHW. And it is kWh, not kwh. Probably not the best way to go with an old house, more radiators would be easiest, and cheapest. Probably not, but having two smaller ones could work out cheaper and give more options.

Yes, and the blame often goes to ASHPs, not the sizing of them. This is the whole point of this topic, it is to stop this happening. So everytime we see someone say something like "I thought of an ASHP, but they are no good in old houses" or "I know someone that has one, and it is rubbish", maybe my favourite "they are not there yet", which I have no idea what it means. it should always be pointed out that they will work if they the design size and installation is correct.

Isn't that mixing up skill and qualification/accreditation. I have the skills to calculate heat loss, but no certification to prove that. But if there was a way for the equipment manufacturers to say 'show us your workings' then they should not be able to sell the wrong component knowingly.

That was the case if a MCS installer did the job. The system had to supply 99% if the time. So 3.65 days if the year you may need supplementary heating i.e. a fan heater.

Time over time, I read on here that ASHPs are no good for old houses. Can we stop this nonsense. ASHPs, or any heating system, if it has a too lower power output, will struggle. That is what power means. So rather than say an ASHP will struggle, or is the wrong thing to install, tell the true story. The true story is that it may be cheaper overall to install a gas or oil boiler, or a much larger, or even two, ASHPs. And could everyone stop getting temperature, energy and power confused, they are different thing.

OK, I shall stop offering explanations to your problems, not mine.

Or a quip.

Any chance of starting a new thread about this. I see it mentioned, along with other plans, but don't understand what it means, and too lazy to Google it.

If you are used to a gas or oil burner you would expect that. But this is a heat pump, they are designed to work at below there maximum rated power (a bit like a car is used, not often you drive it at maximum power). The reason for this is it is more efficient i.e. the CoP stays higher, so costs less to run. Now you refuse to let it run for very long, so what you are, in effect doing, it doing a very long car journey, stopping every few minutes, and only using third gear. Then complaint that it takes forever and you have not reached the top speed of the car. I take it that because of your condition, you are currently not allowed to drive, so this analogy my be pointless.

Or not. https://www.gov.uk/guidance/powers-of-entry

Ideally, to get maximum power transfer, the return temperature is half the difference between the store temperature and the input temperature. This gets confusing when the boiler is in condensing mode though, that often sets a minimum temperature. That all sounds a bit confused. Say your input temperature is 70⁰C, the store is at 40⁰C. Half that is 15⁰C, so return should be at 55⁰C. But as the store warms up, say to 50⁰C, the return should be 60⁰C.

I bought, for about a fiver, a current activated switch. Using that you could count the pulses, and if you know the power of the heating element, you will know what is going on. I suspect, but don't know the chemistry that well, heating is limited to stop phase change when it is not needed. The thermal conductivity of the PCM will be different when it is a liquid and when it is a solid, and not just because a liquid can flow. Normally when a PCM changes state, it cannot be easily stopped. SA have got around this somehow, and that somehow may be to do with how the material is 'conditioned' during the heating process.

That is just one of the downside of burning wood to keep warm, it don't take long to use it all up. If we decided to burn every years biomass growth of the entire planet (all plants and animals), we would, at current consumption rates, have about 400 days worth.

Amps [A] times Volts [V] equals watts [W] A watt is a joule [J] per second. A joule is the unit of energy. So 300 [A] x 230 [V] = 69,000 [W] I said that it would run for 2 seconds 69,000 [W] x 2 = 138,000 [Ws or J] As a joule is the the force [mass x acceleration] to move 1 kg 1 metre, I used the force of gravity, 9.81 m.s2 so (and I think I did this step right, but starting to doubt myself now) 138,000 [J] / 9.81 [m.s2] = 14,067 kg.

Does sound as though it is possibly undersized. Or the heating curve is no steep enough i.e. it is only putting in 50% the power it can, when it should be putting in say 90%. It is also possible to be a combination of both i.e a small engined car, stuck in 4th gear, going up a steep hill. It will make it, but it will be slower

I was qualified to fit inverters, really quite simple for a qualified electrician, most will have covered in when they are updating their Part P. If the electrician does not under stand it, find another one. And it can draw a lot more current than that for a second or two before it blows. So let us say it draws 300 A at 230V for 2 seconds, that is the same as a 14 tonne weight resting on your body.

That is the idea, should start to get the rest of the house warmer. And make sure the thermostat is not above the oven. As your system seems to have warmed the place up a bit, all be it slowly, it seems that most of it is working alright. Don't get hung up on the absolute numbers on the thermostat, it is a warm house you are after.