Setting up a Heat Pump - ASHP

​@BPLightlog welcome to heat pump ownership, a world of joy and frustration at the same time! :-)

What system did you have installed? 

my thoughts (not dissimilar to ​@jason.lewis):

• Circulation pump - I settled with on demand. But this is mainly because my heat pump is so oversized, and normally only needs to be on for half the day. With a properly sized system, continous should be the way to go. 
• Heating - set a schedule or not. Depends on two things. House occupation, if you are in the house most of the time I’d run the system continuously with a well dialled in weather compensation curve, if the house is only occupied morning and evening, then a scehdule makes sense. The second consideration is… You guessed it, its whether the heat pump is sized correctly. If the system is significantly over-sized you’ll want to operate a schedule to avoid the house over-heating. Our house is occupied 24/7 (work from home) but I have a schedule to turn off mid morning and then on again mid-afternoon till 9pm, otherwise the house over heats most of the time (below 0C being the exception).
• Setback - useful overnight or not. If it’s a Daikin you might find the start up surge wakes you up, as Jason mentioned. Daikin’s have an annoying habit of running at 100% on every startup to get up to temperature, it can do this often if the pump is running during regular defrost operations (typically +5C to -2C outside). If you are sensitive to noise it’ll bother you. If not, then run a set back. There are ways round this through diving deep into the settings, but that’s not for this thread, and is Daikin specific. 
• Quiet Mode - does this affect efficiency. Yes. Typically it restricts output capacity by limiting the fan speed, so efficiency will take a dive. There are caveats to this, and some people have found it useful during DHW cycles on better quality heat pumps like Vaillants, but not something to explore at this stage I’d suggest. 
• DHW - schedule and reheat or just schedule? Depends on DHW usage. As Jason said, early afternoon will get the best efficiency due to warmest part of the day, however if you have a ToU tariff and cheap electricity overnight it may make sense to make use of this. The other consideration is how quickly you get through the water and what you set your reheat settings at. I have a large 300l tank, I’ve settled on reheat only with a 20C hysteresis. We heat to 48C, and when the tank stat reads 28C we can just about get away with a short shower (top of the tank is more like 35C), and it’ll reheat the tank. Sometimes it’ll reheat the tank every couple of days, sometimes twice a day, it depends what the teenagers are up to. The house is well insulated enough we don’t ever miss the heating being off for an hour. If you don’t have a well insulated house you might miss an hours heat during a cold day. However if you are running the heating continuously it’s likely the thermal mass of the building will see you through that time. 
  
  Hope that gives you something to think about. *note much of this is also applicable to running a system boiler efficiently.