ᐅ Underfloor heating with an air-to-water heat pump. House gets too warm when the sun is shining.
Created on: 4 Dec 2019 14:18
C
chewbacca123
Hello everyone,
I have a general question.
We moved into our new build four months ago. The living area on the ground floor has three large floor-to-ceiling windows facing south. We have underfloor heating and an air-to-water heat pump.
It provides a really comfortable temperature inside the house, but we have a problem – whenever the sun is shining in winter, even if it’s -2°C (28°F) outside, the temperature suddenly rises to 24°C (75°F) in the living room. It gets uncomfortably warm in here, and the underfloor heating can’t be turned down quickly.
Should we assume that the large floor-to-ceiling windows are responsible for the heat gain? A photo of the south-facing side of the house is attached.
What would you do – always lower all the blinds as soon as sunlight is forecast? That seems quite annoying...
We have motorized blinds controlled by Somfy. Would you consider buying a sensor that automatically lowers the blinds at a certain temperature?
Thanks in advance for your replies.
I have a general question.
We moved into our new build four months ago. The living area on the ground floor has three large floor-to-ceiling windows facing south. We have underfloor heating and an air-to-water heat pump.
It provides a really comfortable temperature inside the house, but we have a problem – whenever the sun is shining in winter, even if it’s -2°C (28°F) outside, the temperature suddenly rises to 24°C (75°F) in the living room. It gets uncomfortably warm in here, and the underfloor heating can’t be turned down quickly.
Should we assume that the large floor-to-ceiling windows are responsible for the heat gain? A photo of the south-facing side of the house is attached.
What would you do – always lower all the blinds as soon as sunlight is forecast? That seems quite annoying...
We have motorized blinds controlled by Somfy. Would you consider buying a sensor that automatically lowers the blinds at a certain temperature?
Thanks in advance for your replies.
Joedreck schrieb:
I seriously doubt whether you can really save on wood. It strongly depends on the respective prices and the efficiency.
@Bookstar COP including domestic hot water? And do you actually like the heat pump now?As I wrote before, if I can run the heat pump about two months less overall, then I’m looking at a net saving of around 300–400€ (~$330–440). You just have to reduce consumption a lot. It’s all about volume.Otherwise, today was a good day, lots of sun, so a lot of warmth in the house without needing to light the fireplace. The photovoltaic system generated electricity, the battery storage got fully charged, and tomorrow I can drive to work with a fully charged car.
So far this month, total consumption has only been 297 kWh. In September it was 1030 kWh. Definitely a really poor month.
Joedreck schrieb:
I seriously doubt whether you can really save on wood. It largely depends on the respective prices and the efficiency.
@Bookstar COP including domestic hot water? And do you like heat pumps after all now? Yes, including domestic hot water, I currently think they are good...
Zaba12 schrieb:
As I mentioned before, if I can run the heat pump two months less in total, I save around 300-400€ (adjusted). You just have to reduce consumption a lot. It’s all about the quantity.
Otherwise, today was a good day, lots of sun, so the house stayed warm without using the fireplace. The photovoltaic system generated electricity, the battery storage is now full, and I can drive to work tomorrow with a fully charged car.
So far this month, only 297 kWh (kilowatt-hours) have been used. In September, it was still 1,030 kWh (kilowatt-hours). So it’s really been a bad month. Sorry, I don’t quite understand. You save at least 300€ by not running the heat pump for two months, even though you have to buy wood?
Just for comparison: Bookstar’s current cost per kWh of heat is about 6-7 cents.
@Bookstar in the end, do you still recommend heat pumps?
Ötzi Ötztaler18 Oct 2020 17:33
The heat pump from @Zaba12 actually doesn’t seem to be set up very efficiently. Heating costs during the transitional period are really quite high…
Currently, the temperature throughout the house from the basement to the upper floor is 24 degrees Celsius (75°F). I experimented a bit with the heat pump, and my air-to-water heat pump handles a nighttime setback very well. From 5 p.m. to 8 a.m., it did not cycle, and from 9 a.m. to 5 p.m. today it ran continuously, consuming 6.1 kWh. It used 0 kWh from the grid, with 100% coming from solar panels and storage. I think that’s pretty good.
PS: Outdoor temperatures have been between 0 and a maximum of 7 degrees Celsius (32 to 45°F) for days.
PS: Outdoor temperatures have been between 0 and a maximum of 7 degrees Celsius (32 to 45°F) for days.
I can only speculate, but let's work this through. The charging station at work showed 11 kWh charged last week after charging (remaining range was 38 km (24 miles)). That was about the remaining range I used to have when I got home last fall. Let’s add a 2 kWh (0.7 gallon gasoline equivalent) buffer. That means 13 kWh per day for the car.
I can reasonably estimate the base electricity consumption of the house (excluding showers, washing machine, dryer, dishwasher, TV, Alexa devices) based on the vacation period at the end of August. It was about 5 kWh per day for 10 days in a row.
So, the bare house consumption without residents and without heating but including car charging is 18 kWh. Correct?
On 16.02 and 26.02, I took photos of my utility meter showing 4188 kWh and 4428 kWh. That means 240 kWh grid consumption over 10 days with heating. So, heating and usage by 4 people in February (the winter month) would account for an additional 6 kWh per day.
Now, some might think I am exaggerating assuming the electric car and base consumption. There were days when consumption went over 30 kWh. But the bill adjustment really annoyed me at the beginning of this year, so I want to start using the heat pump as late as possible this year.
It’s also possible that the electricity installment payment was too low at €65.
No idea, it was the first winter after all.
I can reasonably estimate the base electricity consumption of the house (excluding showers, washing machine, dryer, dishwasher, TV, Alexa devices) based on the vacation period at the end of August. It was about 5 kWh per day for 10 days in a row.
So, the bare house consumption without residents and without heating but including car charging is 18 kWh. Correct?
On 16.02 and 26.02, I took photos of my utility meter showing 4188 kWh and 4428 kWh. That means 240 kWh grid consumption over 10 days with heating. So, heating and usage by 4 people in February (the winter month) would account for an additional 6 kWh per day.
Now, some might think I am exaggerating assuming the electric car and base consumption. There were days when consumption went over 30 kWh. But the bill adjustment really annoyed me at the beginning of this year, so I want to start using the heat pump as late as possible this year.
It’s also possible that the electricity installment payment was too low at €65.
No idea, it was the first winter after all.
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