SteamyTea

Other than the faff, and a bit of extra cost, I can not see a down side of running more/larger MVHR pies. We could do the numbers and work out what the optimal size pipe area is. Building Volume x ACH x Delta T x SHC x hours = Energy. Then, from one of my temperature distribution charts, proportion the hours. May find that you can have a low airspeed in the pipes and cover a lot of your heating with just FCUs.

Lets make an assumption that for 200 days a year there is a 10°C temperature difference, that will be, over 10 years: 48,000 [h] x 10 [K] x 240 [m2] x 0.25 [W.m-2.K-1] = 28,800 kWh 48,000 [h] x 10 [K] x 240 [m2] x 0.12 [W.m-2.K-1] = 13,824 kWh 28,800 - 13,824 = 14,976 kWh Assume an energy price of 8p.kWh-1 14,976 [kWh] x 0.08 [p.kWh-1] = £1,198 So you are probably going to be quid's in.

Can you do a Google image search and see what comes up?

Easy to do if you can pipe directly from a unit in the loft.

Or double up the diameter and get 4 times the airflow.

What they do in St. Ives. Costed in at the start of a project.

Follow up. My old meter has two LEDs. First picture is with the CC OptiSense sensor in place, which I notice has its own red LED that flashes in synch with the meter one, so should be easy to test out my homemade logger. Second us just the two LEDs.

Ah, I missed/forgot the winter 3 months. Would be interesting to see CoP by areas. I wonder if the dryer east of the country gets better results than the warmer, but wetter, west.

It is all documented what to do. https://www.npl.co.uk/si-units

Never really understood what that is. Is there a mechanical term, like there is for water. Pressure and Back Pressure. Though what you are meant to do with that knowledge. Think you end up with static and dynamic pressures.

And that is why I pick up on it so often. If this online community wants to be taken seriously, then a good start is to use correct terminology. None talks about the joules when they talk about 'life energy', it is because they talk bollocks and can't count.

How do you work that out from the annual figures? The overall CoP may be 5.9, does not take into account seasonality changes. Though it does seem very high.

And the solar intensity may be 20% higher than normal.

Does your meter have 2 LEDs, one for direction and one for quantity? I seem to remember that my neighbours smart meter has 2. My mother has a smart meter (broken as no display) but think it has two LEDs on it. Shall check when up there this weekend. I have an old one, so just the one LED I think. Should go and look. Many PV systems use a similar meter, so the reverse indication should come on at night. Has anyone checked?

That.

That is the number of pulses, I am interested in how long each pulse is. Trouble with the CT clamp only method is you have to assume a voltage and power factor.

Isn't that the price cap before tax?

About an extra 300W module every year. Or, 750 kWh of diesel. I would try and design to be off grid, then do some costings.

Set it up so you can have unshaded PV in the roof as close to South facing as possible.

Say electricity is 28p/ kWh, then £468.72. Gas at 7p, £684.53. Gas would need to be 0.04793p/kWh.

Very much not random. The k is always lower case, the W always upper case, the h is usually lower case, but as it is not an SI, or even a derived unit, can be either. Convention has time as always lower case, so t for time, s for seconds. S, is allowed at the beginning of a sentence.

Surprising, normally kWh.

in Money or Energy units?

How cold do you think the UK usually is in winter? Not many of us live in the frozen north. Very really below 5°C, 20% of a year, 73 days) Only 0.75% is -3 or below, 2.7 days. (Central England Temperature data set) So a fan heater can sort that out, but ASHPs still have a greater than unity CoP at that temperature.

Have you considered roof integrated PV, similar price to some roofing materials.