Quick Answer: Heating warms air without adding moisture, so relative humidity falls sharply — often to 20-30% when the comfortable range is 40-60%. Dry air evaporates the tear film faster and dries the mucous membranes in your throat and nose. Fix it with a humidifier or passive moisture, the 20-20-20 rule for screens, and deliberate blinking — screen use cuts your blink rate substantially, and dry air makes that far more consequential.

Monday: the heating comes on.

Wednesday: your eyes feel gritty by 3pm and your voice has gone.

The office did not change. The air did.

What does heated air actually do to you?

Four effects, and they interact.

Relative humidity plummets. Warming air increases how much moisture it can hold without adding any, so relative humidity drops. Outdoor air at 5C brought inside and heated to 21C can end up in the 20-30% range, well below the 40-60% generally considered comfortable and healthy.

Your tear film evaporates faster. The eye’s surface is protected by a thin tear film with an oily outer layer. Dry air accelerates evaporation, so the film breaks up between blinks, and that is the gritty, burning sensation.

And your blink rate collapses at a screen. This is the part people miss. Blink rate drops substantially during focused screen work — often to around a third of normal. Fewer blinks means the film is not being resurfaced, and in dry air it has already evaporated by the time the next blink arrives. Dry air plus low blink rate is multiplicative, not additive.

Mucous membranes dry out too. Nose and throat rely on a moist mucous layer for comfort and for trapping particles. Dry membranes feel scratchy, make your voice tire faster on calls, and are more easily irritated — which is one reason the first weeks of heating season coincide with everyone feeling like they have a mild cold.

What raises indoor humidity that actually works?

Five options, in order of effectiveness.

A humidifier, sized for the room. The direct solution. Target 40-50% and buy a cheap hygrometer so you are managing a number rather than a guess. Above 60% you invite mould and dust mites, so more is not better.

Clean it properly, every few days. This is not optional. A dirty humidifier reservoir aerosolises bacteria and mould directly into the air you sit in all day. Empty, rinse and dry daily; deep clean weekly. If you will not maintain it, do not buy one.

Dry laundry in the room. Free, effective, and it turns a chore into humidity. One rack raises room humidity noticeably — just keep an eye on the hygrometer and the windows.

Bowls of water near radiators, plants, an open door after a shower. Each is modest on its own; together they add up in a small room and cost nothing.

And lower the thermostat a degree or two. Cooler air holds less moisture in absolute terms but has higher relative humidity at the same moisture content, so a slightly cooler room is a slightly less drying one. A jumper and 19C is more comfortable for your eyes than a t-shirt and 22C.

What helps the eyes specifically?

Five things, and two are free.

The 20-20-20 rule. Every 20 minutes, look at something 20 feet (6m) away for 20 seconds. It relaxes the focusing muscles and, more importantly, breaks the fixed stare that suppresses blinking.

Blink deliberately, fully. Incomplete blinks are common at screens — the lid does not fully close, so the film is not properly resurfaced. Ten slow, complete blinks every half hour genuinely helps.

Lower the monitor. A screen at or slightly below eye level means your eyelids cover more of the eye surface, which reduces evaporation. A screen high on a stand exposes more surface area, and it is one of the more common ergonomic mistakes in a home office.

Move air away from your face. A heating vent, a fan heater or a radiator blowing across your desk dramatically increases tear evaporation. Reposition the desk or redirect the airflow — this fixes a surprising number of stubborn cases.

And use preservative-free artificial tears if you need them. Widely available and effective for symptomatic relief. Persistent redness, pain, light sensitivity or vision changes are not dry air — see an optometrist or doctor. This is general information, not medical advice, and contact lens wearers in particular should get specific advice, since dry air and lenses combine badly.

5 Mistakes Everyone Makes in Heating Season

Turning the heating up because you feel cold. Dry air feels colder at the same temperature, so the instinct is to raise the thermostat — which dries the air further and makes the sensation worse. Add humidity before you add heat.

Sitting directly in the airflow. A desk positioned in front of a heating vent or beside a radiator gets a constant stream of the driest air in the house across your face for nine hours. This is the single most fixable factor and almost nobody checks it.

Buying a humidifier and never cleaning it. A neglected reservoir puts bacteria and mould into the air you breathe all day. Daily rinse, weekly deep clean, or do not bother.

Over-humidifying. Above 60% you get condensation on cold windows, mould in corners, and happier dust mites. A £10 hygrometer turns this from guesswork into management.

And blaming allergies. Dry-air irritation and allergy symptoms overlap a lot, and heating season also stirs up settled dust when the system fires up for the first time. If symptoms resolve when you fix the humidity, it was the air. If they persist, it is worth investigating properly rather than adding more tissues.

FAQ: Dry Air and Home Office Questions, Answered

What humidity should I aim for?

40-50%. Below 30% causes the symptoms; above 60% causes mould and dust mite problems.

Do I need a humidifier?

Not necessarily — drying laundry in the room, bowls near radiators and a slightly lower thermostat get many rooms into range. Measure first.

How often should I clean a humidifier?

Rinse and dry daily, deep clean weekly. A dirty one is worse than none.

Why do my eyes only hurt at work, not at the weekend?

Screen time suppresses your blink rate, and a home office often sits in direct heating airflow. Both disappear at the weekend.

Does the 20-20-20 rule actually work?

It is widely recommended and helps most people, primarily by breaking the fixed stare that suppresses blinking.

My throat is worse on video calls. Why?

Talking for long periods dries the throat further, and low humidity makes it worse. Sip water between calls rather than during, and keep the room in range.

When should I see someone?

Persistent eye pain, redness, light sensitivity, vision changes, or a sore throat lasting more than a week or two. Those are not dry air problems.

TL;DR:

• Heating raises temperature without adding moisture, dropping relative humidity to 20-30% against a target of 40-60%.
• Dry air plus a suppressed blink rate is what makes screen work brutal in October.
• Get a hygrometer, aim for 40-50%, and clean any humidifier daily — a dirty one is worse than none.
• Move your desk out of the heating airflow and lower the monitor slightly. Both reduce tear evaporation.
• 20-20-20 and ten deliberate full blinks every half hour are free and effective.

Check where the warm air actually blows at your desk. It is the fix people find most obvious in hindsight.