Summer is coming ! Automatic shading for heat waves

[b0bbywan]

Describe your idea

I attended State of the Open Home 2026 in Utrecht and loved the emphasis on getting real-world problems from users to shape the roadmap. This is mine. It's a problem I've been dealing with for years and never managed to solve properly.

I live in Northern France (Lille area). My apartment faces North and East. Every summer, during heat waves, the morning sun hits the East-facing windows hard and the indoor temperature spikes fast. By noon the damage is done.

My current "solution" is entirely manual. I have an automation that opens all shutters at sunrise (North and East). When I see a heat wave coming, I disable that one and enable a second automation that only opens the North-facing shutters. Then every day I have to remember to manually reopen the East shutters in the afternoon when the sun has moved past.

The real problem is sustained heat waves, and specifically missing the first day. If I don't anticipate it and the shutters open as usual that morning, the sun heats up the apartment and the thermal mass absorbs it all. In a sustained heat wave, it does not cool back down. You're stuck with an overheated apartment for the whole duration just because you missed one morning. Being too optimistic about the real end of a heat wave is another issue I met manually handling this.

Beyond heat waves, isolated scorching days are also increasingly common with climate change. Less critical, but it would be comfortable to handle those automatically too.

It feels like exactly the kind of thing a smart home should handle autonomously, but I've never found a clean way to do it.
I don't know how this should be implemented, but the core issue seems to be that Home Assistant doesn't know which direction a window faces. Covers have a position (open/closed/percentage), but no spatial context. If HA knew that, it could cross-reference with the sun's position (which it already tracks) and the weather forecast (also available) to figure out when a window is getting direct sunlight on a hot day, and decide not to open the shutter.

For the UX, maybe something as simple as dropping a pin on the map in front of your window? HA already knows the home's location, so it could derive the orientation from that. No compass bearings, no azimuth math.

Why is this exciting?

It's not a gadget feature, it's a real comfort and health problem. During heat waves, indoor temperatures can make it impossible to sleep, especially for vulnerable people. And with climate change, this is getting worse every year, for everyone, everywhere.

Smart covers are one of the most effective ways to keep a home cool without air conditioning. But right now, using them effectively during heat waves requires constant manual attention. If HA could handle this autonomously, it would make a real difference in people's daily lives.

Potential use cases

Heat wave hits without warning: HA sees the forecast, keeps East-facing shutters closed in the morning while North-facing ones open normally. No intervention needed.

Sustained heat wave: HA keeps the routine going for the whole duration, reopens the East shutters automatically once the sun has moved past every day, and goes back to normal when the temperature drops.

Proactive notification: HA sees tomorrow's forecast is 35°C and notifies you that it will keep the East shutters closed in the morning. You know it's handled.

Different facades, different behavior: South-facing windows get protected around midday, West-facing ones in the afternoon. Each cover follows the sun based on its own orientation.

Anything else?

I know community solutions exist. CCA Blueprint is impressive and the 2500+ message thread on it shows the demand is real. But these all require manually determining azimuth ranges per window and configuring complex automations. To be honest, the setup is complex enough that I never bothered, and I'm probably not the only one. It feels like something that would benefit from being handled at a lower level, where HA does the geometry for you, but I might be wrong about that.
Some commercial systems (Somfy, Loxone) offer sun-protection modes tied to facade orientation, so the concept exists in the wild.

[Petro31]

Why can't you do this with automations? I've seen people do this 5 or 6 years ago with automations.

[b0bbywan]

I thought wild ideas were welcome here, did I misunderstand ?

I've tried, and I'm not satisfied.

[Petro31]

They are, but automation style ideas are typically left to automations. This staunchly falls into that category.

Here's an example from a couple years back: https://community.home-assistant.io/t/automatic-blinds-sunscreen-control-based-on-sun-platform/573818?u=petro

as a macro https://github.com/langestefan/auto-sun-blind

[b0bbywan]

Thanks! I've just taken a quick look now, but I'll make sure to take a deeper look before the next heat wave.

But let me be honest, if those might be great solutions, the setup UX looks terrible. I'm not blaming the community who built this, I really admire the work on the math side. This is a genuinely hard problem, especially on the UX side, and that's exactly why I posted here. Blueprints are great for power users, but this will never reach normal households at that level of complexity.

I still feel that being able to add more context to a window, especially orientation, maybe size, would be really helpful to building automations more easily. It's not just about covers. I remember following discussions on https://github.com/jmcollin78/versatile_thermostat regarding auto TPI learning features. Developers really needed window orientation and exposure data to adapt valve opening to current weather conditions, like wind and sun. They gave up on that feature if I recall correctly. More context on openings would have helped there too.

Another dumb example, on the same level. For Home Assistant, I have 2 automated covers, but no windows. I didn't install hardware to automate my windows, so for HA they don't exist. Still I have three of them, and they have a huge influence on the temperature in my home.