Cant say i was really given too many options when i bought my setup. The microinverters certainty extract the most from my panels in the winter, which was a priority for me. But they saturate more in the summer. Right now im maxed out at 4900Kw, which for 16 panels is pretty good.
Did you mean 4.9MW? That is some power station 
But if you mean 4.9 kW then yes, my AC inverter maxes out at about that (if you include conversion losses), but can still charge batteries if there is excess unto about 7kW generation from memory - which in practice doesn’t seem to happen.
Yes when I first installed I didn’t put in DC optimisers, then I changed my mind - the difference in solar efficiency in winter was notable.. if you look at my generation graphs you can see when exactly they were installed
Ours were installed last December and we don’t have micro inverters. One standard one seems to be fine.
Haha. Definitely not 4900 kW!
One of the downsides, being on this forum whilst attempting to do the day job. ( was in a teams call discussion over thermal output potential of a European PWR ( EPR)).
1 Like
I kind of hope you were concentrating on the job if you were discussing a potential new PWR…
:-0
I was. Don’t want to get the decimal point in the wrong place with that stuff.
2 Likes
In previous years we’d always get to a point when we decided to turn the heating off. There then followed a period when it was chilly in the evening and sometimes in the morning. The heat pump has changed all that. As we don’t use an internal thermostat, what it does is determined by the outside temperature. For the last few days it’s done little heating, but this evening it’s quite chilly outside, so it comes on and does a little bit of heating. It’s 15°C outside, and the heat pump is on with a flow temperature of 24°C. It’s keeping the house at the target 19.5°C without ever feeling too hot or too cold. And all with a couple of hundred watts of energy use. It’s incredibly clever.
1 Like
Interesting. It’s now about 12° here outside and I’ve been using cooling to keep the house below 22-23 degrees for a few hours, I’ve only just turned the living room cooling off. 
If you didn’t have the pump, would you put the heating on, and if yes, although the pump may be the most pleasant, which is the most cost efficient in your estimation?
Yes, we would have pup something on. Either the gas central heating or the electric fan heater in the sitting room. The pump is far more efficient than either, especially as it can be powered by the sun on a chilly but sunny morning or early evening.
How is your insulation?
I ask as we’ve not heated since 27 April and our sitting room hasn’t dropped below 20c and we’ve tended to need windows open to keep things comfortable so your need to heat came as a surprise.
Here’s the temperature since last weekend.
The heat pump is clever though, running the radiators that cool must mean that you don’t overshoot and end up with too high a temperature in these milder times.
Surely it’s just reacting to the demand in the same as any other modern heating system that has variable output. 
No overshoot on my gas boiler or my aircon - currently running on cool.
1 Like
The insulation is good, but we are not using an internal thermostat. How hard it works is determined by the external temperature and the internal target temperature. It ‘knows’ how quickly the house loses heat, which is obviously quicker the colder it is. They work in a completely different way to a gas boiler when set up like this.
It’s 11.30 pm now. The external temperature is 15°C, the flow temperature is 22° and the internal temperature is 20°. It’s set to turn off completely when the external temperature reaches 19°. It just does its thing in the background and we just don’t have to think about it.
But don’t you have windows slightly open now… it’s cool out, about 8 degrees, but the smell and feel of fresh air in the house at night is beautiful. We tend to close the downstairs windows just after sunset. This evening it’s quite breezy too and the sound of the wind/breeze is very relaxing.
Is this done from a computer algorithm and sensors?
Regarding the insulation, it’s 10°C here now and I’ve had cooling running again from teatime. It’s off now and the living room temp is over 21°C. Warmer than yours even though you have heating on
Same number of people too. Although the dog may help warm the room 
We have the upstairs windows open at night, yes. It’s all quite hard to explain. The thing I was trying to get across is that the pump removes that spring decision of when to turn the heating off. You just set the target temperature and it does its thing, and we don’t feel too hot or too cold.
Got you.. yes I guess when it’s manual you some times put on a layer or open a window wider.., but usually switch off heating at some point in mid to late March .. and might just put on for an hour over ride if very chilly in the evening for the rest of March into early April. By April it nearly always is switched off, unless unusually cold.
I guess we are used to a variation of temp in the house… Mrs SinS and I can feel a bit uncomfortable in some hotels which keep a constant regulated temperature in the rooms… it can be difficult to relax and feel at ease. I guess it’s what you are used to.
But open windows with a gentle breeze and the sound of bird song I’m sure is good for one’s wellbeing .. and is a fantastic way to unwind.
it sounds like you appreciate that as well.
1 Like
Absolutely. Our house overlooks countryside and we get all sorts of sounds, cows, sheep, woodpeckers, screechy buzzards, and the usual songbirds. If the wind is in the wrong direction we also get the 27, but we don’t mention that.
The pump is set to drop the temperature to 16.5 at night 19 early morning and evening, and 18 in the middle of day. It can’t raise temperatures quickly so the two need to be close together. The proof of good setup is a high efficiency (COP). They say that 3 is good for a retrofit, and we are getting 4.6, which both we and the installer are very pleased with.
Getting back to solar, a big advantage over gas or oil is that the sun can run the heating during the day if it’s a bit chilly.
Indeed, we tend to use the solar gain from the conservatory to flood into the house.
But yes we would use solar generated electricity to heat the water, however domestic kerosene is so cheap compared to electricity export tariff, and one of the more efficient oil types, it would become quite an expensive luxury… but I am all set up to do that should kerosene massively jump in price and export tariffs are slashed.
However I do feel electricity is still in appropriately priced in the UK. I understand transmission costs from generation are not appropriately factored in… and here in EA we are fast becoming a massive UK wide power hub with multiple mega off shore wind farm landing and transformer/converter sites as well as nuclear (with non trivial damage and impact to the local environment I might add), and prices are tagged to the wholesale gas price.. which given the amount of renewable and nuclear foundation seems in appropriate… but that is another subject.
The obvious solution to me is to break the link between electricity and gas. It’s clearly complex and I don’t pretend to understand the barriers, but linking the two seems daft.
As for the kerosene, to me the cheapness isn’t relevant. We cut off our gas because we could no longer reconcile ourselves to burning fossil fuel and the cost didn’t really come into it. Everyone thinks differently of course, but it just seems wrong then there are more environmentally friendly options available. The fact we are saving significant sums is a very nice bonus nonetheless!