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

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.

Neues zweistöckiges Haus auf Baustelle mit weißer Blockfassade, pinker Dämmung und großen Fenstern

Joedreck5 Dec 2019 06:47

#31

I can confirm this. Although I have gas and radiators in my old building, my heating runs 24/7 on the absolute lowest setting. Some minor adjustments might still be needed here and there, but the comfort level is indescribable. Never once is it too warm, too cold, or does it take too long to get warm. It is simply always 22°C (72°F).

Winjoe15 Dec 2019 06:58

#32

To return to the original topic:

A south-facing orientation with a view and plenty of sunlight is quite attractive, but it also brings some challenges. The saying "where there is light, there is also shadow" fits well here.

I also see some other issues coming your way:

In summer, without any shading, you will be baking outside and roasting inside. Or you’ll be sitting indoors in bright sunshine with artificial lighting.
You should carefully consider having a terrace in the basement level right in front of the bedroom window. On one hand, the living area is on the ground floor—probably including the kitchen, dishes, etc.—which means carrying things up and down in order to enjoy the terrace. On the other hand, guests could constantly look into your bedroom, as this seems to be the shortest path into the house, likely also used by visitors. Personally, I would find that difficult...

Here is an idea to provide a combined solution to these various challenges (at least from my perspective and as long as I have not misunderstood your floor plan). The terrace could be built on stilts or posts, at roughly the height of the left extension, possibly with stairs leading down to the garden. Above this, add an awning or roof. Of course, the construction should be visually appealing.

You can access the outdoors from the living area without changing floors
No one can look into your bedroom
Shading both above and below
Still a clear view of the greenery both above and below

With the south-facing orientation, the sloped site, and the selected layout, this is certainly an interesting challenge.

ypg5 Dec 2019 11:18

#33

Winjoe1 schrieb:

To return to the original topic:

Uh... and all the likes... It seems your reply is in the wrong thread. This is not about a floor plan; it’s about heat gain from south-facing windows in existing buildings.

ludwig88sta5 Dec 2019 12:05

#34

Tego12 schrieb:

We have the awning installed directly under the patio roof (mounted on tracks)... so there are no issues. Moisture doesn’t get in even during rain, even if the awning is extended. Since the awning is integrated into my smart home system, it retracts automatically in rain or strong wind (although that might not even be necessary).

Without a roof cover... good question, but obviously, with rain and dirt, it could quickly start to look bad.

Do you have a photo of your sunshade handy?
Nowadays, aren’t there fairly weather-resistant awnings available that can even withstand rain (like with nanotechnology or something)?

Because I don’t like a fixed overhanging roof, like you often see in urban villas, plus it also reduces the heat gain for warming the house!

As @Mottenhausen already mentioned, it’s often recommended for direct south-facing orientations. But that’s the downside. I know from my parents’ house, where in summer they lower all the blinds on the south side to keep room temperatures manageable and also because of the plants on the windowsill.

@boxandroof, do you have a heat-reflective coating on your south-/west-facing windows? Can you recommend anything?

hampshire5 Dec 2019 13:14

#35

chewbacca123 schrieb:

Should we assume that the floor-to-ceiling windows are responsible for the heat?

Yes. Because the sun’s radiant heat passes through your windows—unless they have special glazing.

chewbacca123 schrieb:

What would you do? Always close all the roller shutters as soon as sunny weather is forecast? That’s kind of annoying…

No, I wouldn’t lower the roller shutters at 24°C (75°F) inside. @haydee has the simple solution: open the windows.

chewbacca123 schrieb:

We have roller blinds from Somfy, would you buy the sensor that automatically lowers the blinds at a certain temperature?

If anything, I’d control them based on sunlight combined with room temperature.

Occasional 24°C (75°F) in the living room is still within my comfort zone, so I wouldn’t invest in structural measures for that.

boxandroof5 Dec 2019 13:20

#36

ludwig88sta schrieb:

Do you have a heat protection coating on your south-/west-facing windows? Can you recommend anything?

No, that was just an idea in case other solutions don’t work.

ᐅ Underfloor heating with an air-to-water heat pump. House gets too warm when the sun is shining.

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