Abby Normal wrote:

That's good, let the sun warm up the home during the
day, then let the heat pump maintain a comfortable
temp until you fall asleep then set it back.

Yep, your original claim that

Setback has a value, just not with heat pumps.

was always just plain wrong.

And you dont necessarily have to use solar to come back
off setback either, the other obvious possibility when solar
isnt practical is to come back off setback after midday
when the heat pump can get back to normal temp for
the evening a reasonable time with no one in the house.

Just keep it cool until until the next afternoon when
the sunshine warms your house back up.

So if they do not mind those cold temps when the experience
nice low wet bulb temps when getting out of the shower on those
winter mornings why even bother setting it back in the first place.

Basically because that saves power when you
are asleep when its vastly more economical to
heat the bed rather than the entire house.

Just keep the temp set low all the time. With a passive solar design,
It could even rise above the set point on a sunny winter day for free.

Depends on how the passive solar is done. Many find that once the
sun has gone, that its not warm enough for comfort and so it makes
sense to use a heat pump to keep the place warm enough in the
evenings and to go onto setback once you have gone to bed.

So now you stayed up all night

No I didnt. You cant even work out the basics on timezones either.

to basically say why bother making the system recover from night
time set back mainly because it can't without some extra help. The
extra help is sunshine, strip heaters, an oversized system or a
dedicated 'recovery from night time set back' system.

What matters is what is the most economic way
to come back off setback with a heat pump.

That can make setback with heat pumps very viable. You
pig ignorantly claimed setback isnt viable with heat pumps.

You have given up on the overnight set back,

No I havent.

so we are back to the day time setback where
I already said, "recover while the sun is shining".

Its just one way of doing setback with a heat pump.

The other obvious approach is the ductless
split system added to the primary system.

Another is just coming off setback after midday
with plenty of time to get back to normal temps
for the evening with more useful outside temps.

Your original claim that setback isnt viable with
heat pumps has always been just plain wrong.