Air conditioner / Instantaneous water heater as heating

Hi,

thanks for the amounts. I tried to design a site plan showing roughly how it should look. I included the air conditioning unit and wood stove in the site plan.

Ground floor:


Upper floor, the gray area is the roof slope (without knee wall)



My problems are still the hot water and the heating in the bathroom. Because I read that an air conditioner in the bathroom makes no sense due to drafts or doesn’t work because of the high humidity.

Regarding the 20Mwh, I deliberately chose it higher. Because both like it warm and 20 degrees is too cold (discussion already held several times – then you have to pay for it). The room temperature will certainly be 22-23 degrees. I hope this will regulate itself when the first bill arrives.

Domestic hot water heat pump:
If I install this, it runs on electricity and heats the water with ambient temperature and electricity – correct? Now I found various tables on the internet where the electricity consumption can be roughly calculated. With 40L water consumption per person (so times 2) this would require about 4KW (almost half as much as the DLH), can this be? Is this realistic? How high is the electricity consumption roughly if no water is drawn that day?

Bathroom heating:
Which heater would you install in the bathroom?

I hope I didn’t forget anything and accounted for everything.

Thanks

Domestic hot water heat pump:
If I install this, then it runs on electricity and heats the water using the ambient temperature and electricity – correct? Now I have found various tables on the internet where the electricity consumption can be roughly calculated. With 40L water consumption per person (so times 2) it would require about 4KW (almost half as much as the DLH) – can that be true? Is this realistic? How high is the electricity consumption approximately if no water is drawn on that day?

Then on the page you also found a figure of about 400 kWh for a 2-person household per year. That is realistic. With a good system even less.

One problems are still the hot water and the heating in the bathroom. Since I read that an air conditioner in the bathroom makes no sense because of drafts or does not work because of the high humidity.

When heating, the humidity is not problematic, but air conditioning alone in the bathroom is not so comfortable. For the base load, I would still install it in many cases. On a low setting, you hardly feel any drafts, and you can also link the air conditioner with the light switch or a presence detector that turns off the indoor unit when you are in the room. Additionally, I would install a radiant heater. For example, infrared heaters in the mirror or on the ceiling, or electric underfloor heating with a timer. Even the smallest panels are sufficient; it does not really have to heat the whole room. Your bathroom has only one exterior wall, so the heat demand is correspondingly low. If you insulate the wall on the inside (e.g., PIR and then drywall (moisture resistant) in front), the heating load will be very low, and then you might be able to do without an additional indoor unit and heat only with a radiant heater.

What is the approximate power consumption if no water is drawn on that day?

That depends on the model. Radiation losses are naturally present compared to the DLH. For a 200-liter hot water storage tank, you can expect about 30 W of radiation losses. However, these go into your heated area. Therefore, they can be neglected during the heating season.

Hi,

to take the BWWP to the extreme, I came up with the following idea. If I place it in the living room under the stairs, then I could draw in the draft in summer from outside and in winter from inside, right? Since there is a wood stove in the living room, it would then help to use the heat pump more effectively – right?

If the climate does not cause any problems with humidity, then I will definitely install it. Just heating and cooling in the bathroom makes little sense, even in summer.

Then I will enter this into my table and take a look at the numbers.

Thanks

To push the BWWP idea to the extreme, the following occurred to me. If I place it under the stairs in the , then I could draw in the draft in summer from outside and in winter from inside, right? Since there is a wood stove in the living room, it would then help to use the heat pump more efficiently – right?

Such a BWWP has an air throughput of about 300 m³/h. In the living room, which is 60 m³, that would be 5 times per hour. That's quite a lot, and together with the split air conditioner, it won't be pleasant to live there. In addition, depending on the model, the sound power level is between 50 and 60 dB. That has nothing to do with the 20 dB of split air conditioners; it’s simply annoying. Technically, it works if the outlet also goes into the room. If the outlet goes outside, you get negative pressure in the apartment -> plus chimney = game over. If you don't have a basement, there are two options for installation in the technical room. Intake and exhaust in the room. But the room will be too small for that. Intake and exhaust outside. Efficiency in winter is lower, but better than DLH. In your floor plan, I see only 3 indoor units. I would simply use the Hitachi Yutampo solution and charge the BWWP via the outdoor unit. Then you don't have the air ducting problem and can also place the heat pump under the stairs because it makes no noise.

Hi,

thanks for your idea.

But there will be a fourth indoor unit added for the bathroom. I thought it wouldn't work because of the humidity. Since it is only used for heating, that's probably not a problem.

The positioning in the living room was just an idea because it will certainly be the warmest room and the wood stove is there. If this is not a good idea, then we will put the unit in the installation room which we still have to plan (possibly behind part of the kitchen or a small extension next to the kitchen). Then the question arises whether the Hitachi Yutampo makes sense. The SCOP is pretty much the same as that of the BWWP and if I do the intake and outlet to the outside, it is feasible. The Hitachi Yutampo system costs about €1000 more than a BWWP without an outdoor unit.

I hope I have now planned everything.
4 air conditioning units (living room, kitchen, bathroom, and bedroom)
1 BWWP
possibly an electric underfloor heating or heater in the bathroom for short-term and quick heating if needed
wood stove which will certainly help save a lot of electricity on cold days.

All of this is to be connected with the smart home and the power consumption will be recorded and evaluated per air conditioning unit and BWWP to get an overview of efficiency and consumption values.

If the photovoltaic system is added next year (maybe even at the end of this year), it will certainly be a comprehensive and hopefully future-proof solution.

What do you think, this should work compared to a conventional fossil heating system?

Great how I am being provided with information here and what ideas come up.