Sore throat in the mornings?
October 13, 2015 11:13 AM   Subscribe

We have natural gas forced air heating in our old house. I notice that every year when it gets cold and heat comes on we all start sneezing and wake up with sore throats. Is this a consequence of forced air?

I suppose this may be confirmation bias, but it seems to happen every year around this time, in the mornings. It doesn't happen in the summer. It coincides with cold weather, change in temperature so that could be it. But we all get similar symptoms, coughing and sore throat. I initially suspected dryness due to cold temps and forced air but that doesn't seem to be the case, the relative humidity is approximately the same compared to august (around 60%).

Any thoughts?
posted by aeighty to Home & Garden (19 answers total) 7 users marked this as a favorite
Cold air holds less water, which means the Absolute humidity is lower, your throat feels drier because it is drier. Buy a humidifier.
posted by Confess, Fletch at 11:15 AM on October 13, 2015 [9 favorites]

Just to get an easy solution out of the way, you're replacing your air filter before turning on the heat, right?
posted by Phredward at 11:15 AM on October 13, 2015 [5 favorites]

Post-nasal drip? Classic symptom is morning sore throat.
posted by St. Peepsburg at 11:16 AM on October 13, 2015 [2 favorites]

If you're able to confirm that the humidity is the same, then dust from ducts and vents that haven't been used in months may be the problem. You can have the ducts cleaned, and clean vents and change air filters yourself.
posted by asperity at 11:16 AM on October 13, 2015 [3 favorites]

dust from ducts and vents that haven't been used in months may be the problem

Is undoubtedly the problem.
posted by three blind mice at 11:28 AM on October 13, 2015 [2 favorites]

the relative humidity is approximately the same compared to august (around 60%)

Is this the relative humidity inside your home, or the weather outside? I'm guessing it's probably the later, since most people don't have hygrometers. If so, your indoor relative humidity will be significantly lower. If you heat air without adding or removing any moisture, the relative humidity will drop by about a factor of two for every 10°C.

Try getting a humidifier for your bedroom.
posted by aubilenon at 11:29 AM on October 13, 2015

There is definitely dust contributing to the issue. Unless you have someone come in and clean them, or somehow block them off so nothing accumulates in there, there's going to be an initial throat-clearing when you turn the heat on. I usually run humidifiers just to get the dust to settle faster, change the sheets the next day (particularly blankets and pillowcases) and vacuum extra the first few days, plus make sure to take my zyrtec.

There may also be a humidity component to how you feel.
posted by Lyn Never at 11:32 AM on October 13, 2015 [2 favorites]

Do you sleep with your mouth open? If yes, that's why your throat is drying out.
posted by easily confused at 11:33 AM on October 13, 2015

It probably isn't too dry in your house at this time of year in your climate (I won't put the OP's location out in public here, but it is in their profile). Indoor air being too dry at this time of year is unlikely. It isn't that cold out and it isn't particularly dry out. Still worth investing a hygrometer to check the indoor humidity as it gets colder, assuming the number you give is outdoor humidity, but that isn't likely to be the problem.

It could just be dust from your furnace ducts.

It could also be poor air quality in a number of other dimensions. Is your home relatively recently build and/or fairly well sealed? Do you have an HRV? This time of year is often the worst for indoor air quality as we tend to shut all the windows, but the difference in air temperature between the outside and inside is not very large, so there is very little air exchange through the cracks in the building envelope. Pollutant concentration tend to build up in our indoor air. If you think this may be a problem, you might want to have a look at the ventilation system in your house.
posted by ssg at 11:40 AM on October 13, 2015

Is it only noticeable right after the heat turns on, or does it stay bad all winter?

I second changing any air filters on your system (and maybe upgrading to a higher-quality one). Duct-cleaning is kind of a "maybe, maybe not" thing that may depend on your specific situation -- here's a guide from EPA on how to determine if it's a good option for your case.

You can also manage your response to allergen exposure at the nasal level by adding NeilMed sinus rinse, antihistamines, and/or steroid nasal sprays.

On a completely different front, morning sore throats are a sign of sleep apnea and apparently apnea symptoms can become worse in the winter due to drier air (or stuffier noses). If you have any other symptoms (including morning headaches, sleepiness, fatigue, etc.) you could consider getting screened.
posted by pie ninja at 11:42 AM on October 13, 2015 [2 favorites]

Indoor air being too dry at this time of year is unlikely. It isn't that cold out and it isn't particularly dry out.

When the heat is on in my house the humidity goes from about 30-35% to about 15% in an hour. 15% is down in the "too low" range for most people. That said, I think it's likely a dust and/or air filter issue but a humidifier (and a hygrometer) is a good investment
posted by jessamyn at 11:43 AM on October 13, 2015 [1 favorite]

Response by poster: I actually do have hygrometers in the 3 bedrooms and they are all showing 60% or so. To be honest, I dont understand this whole relative humidity business so I'm not sure whether I do need a humidifier or not. I'll run one for the next few days to see if it improves the situation.

I have replaced the filter.

I will also look at getting the ducts cleaned.

@pie ninja: I believe it's pretty bad all winter but it seems to start with when the furnace starts.

@ssg: any advice on how I can shop for inlet ventilation? I suspect it may be part of the problem. The house is quite old (early 70s).

Finally, I'm not the only suffering from these symptoms -- the whole family is.
posted by aeighty at 11:56 AM on October 13, 2015

Best answer: With your indoor humidity at 60%, your house is actually more humid than is desirable. Do not add any more humidity with a humidifier! Make sure you run your bathroom fans when showering and your kitchen fan if you are producing steam or using a gas range in the kitchen. If you don't have these, I would look at adding them. In your climate, too much humidity is a common issue.

Do you have any other sources of moisture in the house? A ventless gas fireplace? Perhaps your furnace exhaust is leaking into the house? Gas range? Lots of houseplants? Dryer venting inside or air drying clothes inside?

If your house is too humid over the long term, you increase the risk of mold, which can cause respiratory issues. Can you see any mold in the house?

It sounds like you have an indoor air quality issue of some type. Fortunately, the answer is generally easy: more ventilation.

Do you have any sort of ventilation system other than bathroom and kitchen fans? I would recommend you get a blower door test to check how much natural ventilation you have. The person who does the blower door test can also recommend appropriate ventilation additions. There are a few different options, but it really depends on how much ventilation you need and how a system can fit in your house.

I really urge you to get someone professional to look at the issue as your whole family is suffering health consequences. I know that the difference made to our house with proper ventilation is huge.
posted by ssg at 12:15 PM on October 13, 2015 [4 favorites]

The waking up with a sore throat thing often happens to me when my sinuses are congested. I have allergies/sinusitis year round, but I find the transition seasons (Spring and Fall) to be the worst for this.

My theory is that because my nasal passages are so congested, I end up sleeping with my mouth open, and then I wake up with a sore throat.

To try to resolve the issue, I would recommend getting one of those sinus rinse/neti pot systems. Use that to rinse out your sinuses once or twice a day. (Make sure you use distilled water, not tap water or spring water.) You can take Mucinex to loosen up the congestion as well.

In terms of the correlation between the sneezing/sore throat and the heat turning on, I do find that the heating system dries out my apartment, but it sounds like that's not your issue. My hunch is that it's more likely some mold or dust which is causing your sinuses to flare up. If this is something that happens when the furnace first turns on but then dissipates, maybe there's some dust that builds up in the system when it's not being used, and then after it's running for awhile, the dust or whatever ends up getting cleared out.

I'm not sure how you could figure out whether this is in fact happening, and I also have no idea how you would resolve this issue, but the sinus rinse thing is pretty risk free and requires minimal time/money investment, so I would give it a shot.

Disclaimer: I know next to nothing about how heating systems work. Also, IANAD, IANYD. I'm just someone with terrible allergies.
posted by litera scripta manet at 12:24 PM on October 13, 2015

Best answer: I actually do have hygrometers in the 3 bedrooms

Oh! Well then your indoor humidity probably is just what you said it is. 60% is not at all dry, so I retract my suggestion to get a humidifier.

To be honest, I dont understand this whole relative humidity business so I'm not sure whether I do need a humidifier or not

Absolute humidity is how much water vapor there is in air. For instance, maybe there's 5g of water vapor in 1kg of air. But there is a limit to how much water vapor you can dissolve in the air, and that limit varies with temperature. Hot air can hold much more water than cool air. Relative humidity is how much water there is in the air compared to how much water there could be, at that temperature. This matters, because this is what affects how readily water will evaporate, which affects how well sweat cools you, how fast your towels dry, whether mold can grow, and whether your mucous membranes dry out.

For some concrete numbers: A kg of air at 10°C can hold around 9g of water. No more water can evaporate once it reaches that humidity - that is 100% relative humidity. 4.5g of water would be 50% relative humidity. But at 20°C, a kg of air can hold about 15g of water. So if there's still 4.5g of water in it, that's now only 30% of the higher total capacity - so the relative humidity is 30%. If you try to cool air past 100% relative humidity, any extra water more than the air can hold will condense into fog, rain, dew, frost, or whatever.

So the air coming out of your heater will have a lower relative humidity than the air going into it.
However, your hygrometers measure relative humidity, and they say 60%, and that's not too dry, so you don't need a humidifier. Sorry for the red herring of a suggestion!
posted by aubilenon at 12:48 PM on October 13, 2015 [2 favorites]

Response by poster: @ssg, we don't have any of those things you listed, although I can't be certain that furnace exhaust isn't leaking into the house. Although I suppose if it was, it would increase CO level and then the monoxide detector would complain.

We don't have any visible mold, and the humidity levels hasn't gone up (maybe a couple of percent) since the temps went cold...and we shut all the windows. I guess if there was particulate of some sort in the air, it would affect our respiration much more due to the ventilation (windows closed in colder weather) and further be exacerbated by the negative effects of furnace-heated air.

I'll get in touch with indoor quality air specialists and see what the recommend.

Thanks everyone.
posted by aeighty at 12:50 PM on October 13, 2015

My mom discovered that if she lets the first-hot-air-of-the-season run for a few hours with all the windows open and maybe not be in the house if possible, she could avoid the days of allergy/cold symptoms she usually had.
posted by CrazyLemonade at 2:02 PM on October 13, 2015 [1 favorite]

Best answer: If you don't have any big moisture sources, it does sound like your house is under-ventilated at this time of year. When it gets colder outside, your indoor RH should generally go down somewhat.

I'd recommend your first step is to get a blower door test to see how much natural ventilation you have. Indoor air specialists deal more with specific issues. I'd recommend someone like City Green to do a blower door test. It shouldn't be much more than $100.

As a bonus, if you plan on adding ventilation, you can see where your house is leaking air now with a blower door test and seal those leaks up to save yourself some heating cost.
posted by ssg at 4:02 PM on October 13, 2015

As an FYI, relative humidity is defined as the ratio of water vapor in a given volume of air at a given temperature to the max water vapor a given volume of air can hold at that same temperature. RH depends on temperature. 60% RH isn't the same amount of water at 85 degrees vs 65 degree, as colder air is capable of holding less water - ergo you may actually still need a humidifier if your symptoms start at heating season but your RH remains the same. There is overall less water vapor in your air.

Just think about how swampy it can feel at 85 degrees vs how it will never feel like that at 30 degrees, and RH becomes more clear.

Other thoughts include checking all your furnace filters and getting your ducts cleaned.
posted by annie o at 10:06 PM on October 16, 2015

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