SteamyTea

I am not so sure. Say oil is available at 60p/litre. To just produce electricity from a diesel generator will probably have an efficiency of no more than 25%, and at small loads 10%. There are roughly 10 kWh in a litre of diesel, so somewhere between 2.5 kWh and 1 kWh of electricity, so at 60p/litre between 24p/kWh and 60p/kWh, with the vast majority being at the lower end (a few hundred watts). Different if you can get some thermal energy from it as well, and store electricity, but the capital cost becomes high.

You have to make sure that your insulation cannot be wind washed. That would bypass all advantages. Then you have to consider condensation risk. 1 sheet of glass or 3 in the windows does not affect airtightness, it is the seals and joint to the openings that is important. There is thermal bridging to take into account here. Frequent testing is important if it can be done cheaply. If you get to 1 ACH then MVHR is important. I think there is a limit where forced ventilation becomes compulsory (<3 ACH?). Can you improve the U-Value the walls and ceilings? Ceiling especially, walls depend on the total exposed area.

Kelvin x angular rotation x Henrys No idea

Fresh. Matured has already started the process, so the wrong bacteria will be there. Aerobic and anaerobic, you don't want the first sort (I think). I have lost contact with the guy I know that commissioned digestors, but maybe a trip to your local old landfill sight or sewage works may help. They often have a person on site that knows about them.

Can you just divide the total amount payable by the number of units. Too hard for me to work out while sitting on the beach.

I realised 30 minutes, and one nano second after posting that it was the FT, not the Sun.

Can you just copy and paste the article. Most people don't feel the need to add to the Murdoch Millions.

How many kWh was that for? Just paid mine, £122.55, I was £0.75 in credit. All electric, even cooking. I used, in total 305 kWh over 86 days. So with everything included, it works out at 40p/kWh. It is the 55.1p/day standing charge that is killing me. Just power would have been 23.4p/kWh. This period last year, I used 479 kWh, this year, 305 kWh, so putting only the top heater on in the 200 lt immersion heater has saved me nearly 200 kWh. Cost about 20 quid, so far has saved me about 37 quid. Only had a couple of luke warm showers, one was last night.

Interesting. I don't know enough about condensing boilers to know how they work, or are meant to work.

When a cylinder is heated from the base, there is a fair amount of turbulence in it. Take away the heat source (no input to coil at base) and there will still be some turbulence for a few minutes. That needs to settle before a true 'spot' temperature reading can be taken. What does this mean?

Comes down to the dump load being a 'thing' that is useful, usually later in the day. So hot water is useful, as is a charged battery. Extra lighting and a freezer at a degree cooler is probably not useful.

How do you know it is condensing? I had a condensing combi when I lived up country. It used to make snow when it was really cold outside.

While I agree with this, freezing at around double last year's prices should help. I just tried to explain the difference between a 3 kW resistance panel heater and a 3 kW A2AHP, that draws 0.8 kW, to my coffee drinking mate. He still think the resistance heater uses less and will store energy for later. He has magical physics that can prove it is better. He showed me a picture of his smart meter as proof. What he actually showed was the unit price, but has convinced himself that it is the daily total. His bill is going to be a shock.

There was a guy over the other place that paid 50k for a micro bio digester. It never worked. I would look at properly designed commercial shit kit. It is one of those things that works better when larger. They are not fit and forget, they take constant monitoring and fettling, then the depleted waste has to be got rid off. And there are tonnes of it.

I cobbled together a logger using an old CurrentCost monitor and a raspberry pi. Then analysed the data in a spreadsheet. Also put this together to make a logger. https://forum.buildhub.org.uk/blogs/entry/946-the-energy-meter-experiment/

It is a log scale though. "Two principal types of scaling of the decibel are in common use. When expressing a power ratio, it is defined as ten times the logarithm in base 10.[5] That is, a change in power by a factor of 10 corresponds to a 10 dB change in level. When expressing root-power quantities, a change in amplitude by a factor of 10 corresponds to a 20 dB change in level. The decibel scales differ by a factor of two, so that the related power and root-power levels change by the same value in linear systems, where power is proportional to the square of amplitude." Let us know how it goes, would heat my house very nicely, and could go back under the window where the storage heater was.

That is up to the individual to decide. £5k would buy me around 6 years of electricity at todays prices. And I would still have £5k in the bank.

Now you are into latent heat of fusion. You would not see the difference. How the first ice stores stayed cool for months.

It is the old 'Up to'. My car can do 73 MPG, I have a picture of the dash that shows it when I got to Exeter, so that was after 200 miles. But usually it does mid 50s. And running around small towns, mid 40s. Which is right? (interestingly my mileage and the official mileage match quite well)

Who are the poorest though? Is it based on claiming benefits, a fraction of median household earning, or total individual earnings. What about shared houses?

I hope not, I am on target to use 3 MWh this year (still under 2 MWh just). My mean price is currently 22p/kWh, so £666 for usage (before meter rental and VAT) Take away the £550 that the government have promised (spent the £150 already on new secondary glazing), my usage should cost around £120 this year and heading into next year a bit. That begs the question, if I do not use enough, will I not be able to get the full £400? Shall just have to up my meter reading to get it, £66 a month will not look to unusual.

To make the sums simple, let us say that the 9.5 kWh system can reliably deliver up to 7 kWh and it will last 10 years. So that is £1000/kWh installed, or, over the lifetime, 4p kWh delivered. Now if you import energy to charge the battery, you have to add the 4p to the kWh price i.e. 20p/kWh on E7, so a total of 24p. If you use your PV, you really need to work out what each kWh it generates costs you. So say your system costs £1000/kWp and each kWp yields 1,000 kWh/year and your system lasts 10 years. Each kWh of electricity costs you 10p. So if used via the batteries, 14p/kWh. The mean price if half is imported at 20p/kWh and half PV generated at 14p/kWh is, once the costs of the batteries is included, works out at 19p/kWh. So up to £1.33/day. That is a mean price, it will vary during the year, winter it will be closer to the higher price of 24p/kWh, summer, no use at all. Now none of that really helps you much as it does not take into account your usage patterns and your generation profile. You may use a lot of electricity in the evenings, in the winter, and very little during the day. Work out your usage patterns (get reading that meter 4 times a day or make a logger) and though PVGIS work out your hourly generation profile. Then see how they match up. Also, consider fitting a storage heater connected to a PV diverter (I assume you already have one for your DHW). One or 2 1.5 kW/10.5 kWh storage heaters can save you a bit on space heating (stick them where they are useful, not out of the way). No use in summer, but the rest of the year it will be useful, sometimes. I don't know what car you drive, or how many miles you drive it, but a more economical car will almost certainly save you more.

No one, apart from the manufactures, actually test the efficiency of their boilers once installed. I would think that overall, 80% is towards the upper limit.

Most of the energy is used keeping goods cool, not the air. The air in a fridge is a few tens of grams, with a SHC of 1. Just a litre of water, mass 1kg and a SHC of 4.2 will swamp the 'noise' of door opening.