ᐅ Air-to-water heat pump – smart thermostat

I can only agree here once again... your thermostat cuts off the heating in your room while you are cooking, and 1-2 hours later, when you have long left, your kitchen cools down...

During that time, you haven't saved anything at all... because the heat was coming from the stove, and the floor got cut off... now the floor has cooled down and needs to be reheated to the target temperature using additional energy... so your heating kicks in again and heats for 1-2 hours until the room is warm again...

The same goes for the fireplace and the sunlight...

That’s not correct. When I’ve cooked for an hour, that corresponds to the heating energy of many hours for this room, and with the fireplace and solar radiation, it’s even more pronounced. Nothing cools down here because the energy recovery ventilator (ERV) opens again after a few hours, and the supply temperatures are very low (the floor takes several days to cool down, as it stores a tremendous amount of energy! Your argument is simply nonsense!). The floor hasn’t cooled down significantly because the energy the room needed was supplied elsewhere. Precisely due to the thermal inertia of underfloor heating, an ERV can save energy! You should not think of underfloor heating like a radiator, which emits heat strongly into the room, but as providing a very controlled few watts of heating power! Even at -20°C (-4°F) outside temperature, my kitchen/dining area needs less than 700 watts of heating power, so then at 0°C (32°F), 500 watts of solar radiation on a sunny day should not cause additional heating energy from the underfloor system that I would then have to ventilate out.

Regarding the fireplace and the sun, you haven’t provided a valid argument. Most heating systems operate based on outdoor temperature plus return water temperature and do not detect the countless kWh from the sun and fireplace, or only detect it much too late. Due to this control method, as you (Mycraft) say, the heating does not turn on 1-2 hours later and have to reheat anything. Underfloor heating, especially, does not work that way (or that quickly).

Does this mean that a fireplace does not reduce the load on an air-to-water heat pump at all during winter?

Because you overestimate them or notice them through the return flow if they were that strong – which I can’t quite imagine in winter yet.

And a fireplace is a luxury that normally has no place in a modern house. I also ordered one because I don’t care, and I can still open a window without worry.

But you didn’t understand how the individual heat carriers work, especially the hydraulics of underfloor heating, and what a thermostat can mess up in that context.

By the way: I planned an exhaust hood – pretty extreme, right?

From my private network, I know 4 houses with heat pumps that each eliminated the need for electrical resistance heating – and strangely, not only do they noticeably save electricity, but no one suffers from the heat. That’s theory versus practice...

@Saruss

This topic has been discussed so many times everywhere... anyone who understands the technology knows that ERR doesn’t help in a modern house...

and I can speak from experience... three years without it... not heating the heat carrier at all is where the savings come from, not from turning off individual heating circuits...

@Bautraum 2015
Yes, a fireplace doesn’t really provide anything except a romantic atmosphere and a sauna-like feeling, well, and of course dirt afterwards...

Sauna feeling? Cool, I want that! I need a stove!