My master bedroom leaves me SO STUFFY every morning. I wake up feeling like I have a cold.

The room sits at the top of the stairs on the second floor, directly across from the foyer. There is a large window that streams hot sunlight into the room if I leave the French doors open, so I keep them closed. Even so, it is by far the hottest room in the house. It’s a west-facing room, so I keep the blinds drawn and have temperature control curtains on the windows. My two dogs sleep in there with me, but they live in my lap and their dander/fur doesn’t bother me anywhere else. I’ve tried deep cleaning the whole room - washing the walls, the carpets, and the linens, and making sure the cieling fan doesn’t collect dust. I’ve had my HVAC serviced to make sure the vents are clean. I have an air purifier running at all times.

I’m wondering if the master bedroom is simply an air trap and all the dust, pet dander, and humidity is sticking and settling there. What can I do to breathe better?

  • It might be worth adding a bit of detail about day and night outside temperatures and humidity, and ideally the inside temperature in the evening and morning. Also you hint at air conditioning - when does it run?
    – Chris H
    Jul 5, 2023 at 6:24

3 Answers 3


Have you checked all your supply and return registers to make sure they are open? Are all your dampers open? What about adjusting registers in the cool rooms to allow more cool air upstairs?

There are duct fans available that can be installed in your existing duct work that will force more air through them, just a thought.

We had a similar problem with a hot upstairs and finally added a whole house to vent from the upstairs into the attic. It drew cool air from the downstairs to the upstairs. Checking the insulation levels in the attic might help too.

Last but not least, You might decide to add a second AC unit, mini split, to take care of the upstairs.


First, have the HVAC system checked out make sure ducts are not blocked, clogged with dust, and the like. But most likely this is not the core problem.

Let me ask you a few questions about weather. Suppose you like your house thermostat set to 70 degrees F or 20°C. If the weather report says 70F (20C) outside, and your thermometer outside your north-facing window says 70F (20C), does your heater need to run? Nope. Of course. Now here's a trick question: Does your air conditioner need to run? It's 70F outside and 70F inside, remember.

Answer: Yes, very much. WHY? Because the need for cooling isn't about the outside air temperature. It's about the sun.

Sunlight is heat. How much heat? 1000 watts per square meter or 300 BTU per square foot. It's a lot of heat. A LOT. and it only bears on the sunward facing sides of the house. Yes, this makes it difficult to "balance" ducting systems so that heating is balanced but cooling is balanced too.

Now, to make matters worse, there's insulation. That should help, but on most houses, most of the structure of the building is outside the insulation layer. That structure has physical mass - and because it has mass, it stores heat. So it soaks up the sunlight all day, and after the sun goes down it is still hot. So it continues to radiate heat for hours, both out to the night sky and also inside through the insulation to your room.

And that's why people run their air conditioners long after the sun sets. This is also why I got into the habit of going to bed very late - because it takes that long for the room to cool off at night, for the building to shed all its stored heat.

Closing the French doors, closing blinds, using "temperature control curtains" - they still catch almost all the solar heat. You hope a little reflects or radiates back outdoors, but mostly they release the heat into the room actually. That can be proven by looking at the reflectivity aka albedo of the materials. 100% is total reflection; the brightest white paint I have is 83% albedo. Typical pastel house colors are in the 50s of albedo (not great) and anything in a middle or darker color has an albedo near zero. Aesthetically preferred roofs are the worst offenders. So yeah, those indoor treatments are doing next to nothing, other than making you feel like you're trying.

  • I would hope that if temperatures are close to your example, it could be solved by less power-hungry means. Like ventilation. Convection (not helped by the extractor in the en suite) and evening sun make my bedroom hot; the solution is just opening front and back windows in the late evening. Early morning fresh air helps too, lowering the temperature of the whole house
    – Chris H
    Jul 5, 2023 at 6:09
  • @ChrisH the problem there is humidity. Everyone thinks of A/C as a temperature thing - actually temp and humidity go hand in hand because human skin is sensitive to evaporative cooling. That's what "wind chill" is. So humidity has a huge part in perceived temperature, so it's part of air conditioning. Reducing 1 pound of air 1 degree F only costs you 0.24 BTU, but removing 1 pound of water from air costs you 1000 BTU. Talk about "power-hungry means!" Jul 5, 2023 at 19:02
  • That's why I asked the OP to clarify the humidity under the question. Your example temperatures are typical for summers here, where we're currently at around 60%, and home air conditioning is rare. When it gets hotter it's not generally too humid.
    – Chris H
    Jul 5, 2023 at 19:58
  • @ChrisH yeah, I've lived in that climate... however America is mostly either a) muggy when it's hot (Great Lakes, Northeast corridor, plantation states) or b) dry but lethally hot (Arizona, California more than 20 miles from the coast). As such, mechanical air is viewed as pretty important. Hardly needs to be energy guzzling, 36 SEER A/Cs exist (of course we don't make em lol). With a tiny bit of brains, we could run the A/C when the solar is producing, and we have incentive to do so since the power company pays very little for solar power anymore. Jul 6, 2023 at 2:36
  • That does cover most of the American population (though the limited areas I've visited in hot weather weren't all like that), and probably extends to Canada too. But though we can guess that the OP is your side of the Atlantic, we still don't know their climate. Certainly using the internal thermal mass of a building as an energy store is a great idea. It's the only way I'd go for home air conditioning, but here a heatwave is merely uncomfortable with insulation, careful use of shade and night ventilation. Rooftop solar of course also reduces solar thermal gain
    – Chris H
    Jul 6, 2023 at 6:05

If you've got a lot of solar gain from glass, shading it from outside will be very effective.

This could mean installing an awning, but even a large parasol can do a good job, or tall potted plants.

You might find that even while they're catching the sun, opening the French doors while leaving the curtains shut makes a useful difference. Opening something on the other side of the home will get airflow. Not if you've got air conditioning running of course.

For the stuffiness specifically, assuming opening the bedroom windows overnight isn't an option (too much intermittent noise here) opening internal doors help, possibly into better-ventilated parts of the house. Just opening the door into my en suite, and opening the window in there just a little, makes a huge difference.

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