ReedRichards

When people come to the house they would either say "Wow, an air conditioning unit" or "Ew, an ugly air conditioning unit" (I assume most people would not recognise an ASHP for what it is). If @jothis still finding big tanks ugly then it must surely be some decades before ASHPs fade from notice.

I have a 12 kW heat pump but I live in a bungalow built in 1980. As part of the requirement to qualify for the RHI my installer came and surveyed the house and calculated the heat loss for every room and added it all together. On top of that they add a margin for the time the heat pump is heating the water (or defrosting) and a little bit of headroom. I have subsequently found out that heat pumps seem to be most efficient when operating at moderate levels of their maximum capacity so I'm not sure what the optimum amount of "headroom" should be.

Where do the pipes from the heat pump need to get to? Can you move the window that is partially obscured by the TV set (?) a little towards Oakcroft and put it the other side of that wall?

So it's "would" affect the output rather than "will" and a hypothetical question?

I have never wanted to interfere with the the compressor or fan settings; AFAIK I don't have that option.

If you're not going to live in the house then the fact that you don't like the look of radiators should not be an issue. And skirting board and plinth heaters still require pipes to supply them which will be as visible as the pipes that supply a radiator.

Surely Underfloor Heating is the only best option if you don't like your heating to be visible or audible?

Surely a radiator looks no worse than a storage heater - which you already have?

I take it you don't know and cannot see how the pipes have been routed?

It seems a little expensive but it's impossible to say without knowing all the other parts (and even then I probably could not price those myself). It's just that you have moved some way beyond getting a "free" heat pump because it would cost less that the RHI. At this late stage an important consideration must be whether it can be delivered and installed in time for the RHI deadline.

The cost has gone up quite a bit if the basic heat pump is still £8,500.

My radiator pipes are split into two zones. The return water from the small zone can either go down the return pipe or backwards through another radiator on the large zone. I can see no reason why it should want to do the latter but it does; when the large zone is off this radiator still gets hot. Rather than trying to figure out why (nothing obvious) I thought it would be easiest to fit a non-return valve to prevent it.

A non-return ("check") valve would presumably solve the problem.

Indeed; typically we might only see temperatures as low as - 3 C on a few nights each year.

I have my DHW on a loop. My cylinder has the secondary return port quite near the top and it does not seem to adversely affect the stratification. That's good in winter but in summer I heat my cylinder with spare solar power, the immersion heater is half way up the tank and I could wish for destratification to take place. If there was such a thing as a three port valve approved for drinking water I would send the return back via the cold feed in summer but such a valve does not seem to exist.

It may depend on the make of heat pump. In my case the "curve" is a straight line connecting a minimum and maximum outdoor temperature on one axis and a maximum and minimum leaving water temperature on the other axis. At the moment I have -3 and 18 specified as my minimum and maximum outdoor temperatures and 50 and 29 as my maximum and minimum water temperatures. My system (all radiators) is specified (in the MCS Certificate) for 50 C water temperature but I have concluded that I don't need 50 C unless the outside temperature is -3 C or below. Today it was about 6 C outside and my heat pump should have been targeting a water temperature of about 41 C. Certainly the house was as warm as I want it to be. And with these new settings I am using much less electricity than when the system was new a year ago - or is it just that last January particularly cold?

Not as such, no. Radiators aren't hi-tech; you can give then lots of internal fins to increase the effective surface area and you can increase their output by blowing air through them with a fan - that's really it.

If you think 4 MWh is excessive, compare it with my 6.9 MWh used in a year. But I live in a bungalow built in 1980. I looked to see where Durnham was but could not find it except as Durham misspelled.

Rads requiring a higher water temperature than UFH? So rads at the expense of economy of heat pump operation? Or super large area rads that can work at the same temperature as the UFH?

Since batteries are not mentioned I think that must mean that it is not battery compatible.

Is it battery compatible? If , for example, you boil an kettle and the battery is supplying some or all of the power, when the kettle switches off the battery cannot drop its output immediately so discharges to the grid as it ramps itself down. So you don't want that to be seen as spare solar power by your diverter and you probably need to have the diverter turn itself off for, say, 30 seconds every 10 minutes to check that the export is still there. If it's not you were just draining the battery.

Fortunately my installer gave me a Grundfos pump from the outset. And the pump itself really is quiet; it seems to be the flow that makes most of the noise.

I have an LG ASHP and a second pump for the central heating. The thing I like least about the entire system is that the flow of water through some of the pipes and radiators is quite audible whereas what I had before was completely silent. But in my previous house the gas boiler had quite a loud pump so maybe it's just pot luck.

The slower the pump speed the greater will be the temperature differential across your radiators. The greater the temperature differential the lower will be the average temperature of the radiator. The lower the average temperature of the radiator the smaller will be its heat output. So the heat pump will have to make the leaving water temperature higher to get the average up and achieve a sufficient output. So either you will be too cold or the heat pump will be working less efficiently than it could.

I was joking but a marine wind turbine costing, say, £1.25 k should very comfortably give you 6 W; the one I looked at said 160 W rated power. You would need to mount it on a scaffold pole and then you would need an inverter and wiring.