Best Room Temperature for Asthma

About asthma

Have you ever wondered what may trigger the inflammatory disease asthma?  Asthma causes symptoms such as tightness in the chest, breathlessness, wheezing, and coughing. Different conditions can affect the severity of asthma; for example, nocturnal asthma symptoms can be worse than asthma experienced in the daytime.1 


There are various triggers for asthma. Factors such as physical activity, infections, cigarette smoke, or cold air are some examples. Substances such as dust mites, pollen and pet dander may also be potential triggers.

Can environmental factors make your asthma flare?

The connection between the environmental factors and asthma

The presence of environmental triggers can worsen asthma by making a person’s airways hyperreactive if the airways become more inflamed. This hyperreactivity can linger even after the trigger is removed. Environmental factors may even alter the response of a person’s immune system, which may magnify the severity of other triggers found in the body. Several studies showed how allergens enhance the negative effects of asthma; for example, we now know that developing a sensitivity to indoor triggers can play a role in asthma developing in an individual. 2

What are the environmental factors that can trigger an asthma flare-up?

Room temperature

Asthma UK says that a cold room temperature can cause asthma symptoms to worsen, as the airways become agitated, and the lungs respond to a decrease in room temperature by tightening.3,4  Cold air can additionally cause asthma flare-ups in an indirect manner if the immune system is more vulnerable to atmospheric pollution or viral infections, and raise the possibility of asthma attacks.Alternatively, a warmer ambient temperature and more humid air can aid common environmental triggers like mould or dust mites to survive, which can further irritate a patient’s allergic asthma.4 A warm room temperature can also cause the level of mites and microorganisms themselves to increase within the household.5 


The Asthma and Allergy Foundation of America explains that asthma patients in humid weather find it more difficult to breathe as humid air is denser. This could be due to the fact that people with asthma are more sensitised to environmental factors that further aggravate their inflamed airways. If patients find that the air is harder to breathe in, then the body temperature may become warmer, leading to sweating and dehydration, which all play a role in triggering asthma symptoms.  Because high humidity levels are common during summertime, extraordinary levels of heat can irritate the airways in a similar fashion to how cold air does.6   

Pollen counts 

When rain droplets and atmospheric pollen interact, the pollen grains are dismantled into minute particles, which are able to travel a greater distance into a person’s lungs, which can cause an asthma flare-up to a higher degree.7 The hay fever that people with pollen allergies experience can impact lung diseases such as chronic obstructive pulmonary disease (COPD) as well as asthma.8

Sudden change in weather 

For young children in particular, the temperature variation during the change from summer to autumn can lead to the recurrence of asthma. Since respiratory diseases are more easily spread when Western schools begin the new academic year, the faster rate of transmission can also be responsible for asthma flare-ups.5


As mentioned previously, rain makes entry into a person’s airways more accessible for pollen by breaking it down.3 Rainy conditions also play a role in the increase of mould and dust mites.9


Since colds and cases of flu are more prevalent in wintertime, asthma patients tend to develop harsher symptoms. Chest infections can further inflame the airways of asthma patients, and cold air in winter can make a person’s mucus production increase, which can also worsen asthma symptoms.  Central heating that is used during winter can also cause air pollution in indoor air.10 


Air conditioners that are used during bouts of warm weather may cause an asthma flare-up.5 During summertime, the air can capture mould, pollen, and other particles harmful to people with asthma, which can then easily be inhaled. Even breathing in warmer air itself can bring about an asthma flare-up.11

Dust mites 

Asthma patients can be negatively impacted by dust mites by inhaling proteins from dust mite urine or faeces. Since dust mites absorb moisture from the atmosphere, these creatures thrive in houses and environments with high humidity and alternately cannot survive in places of low humidity.12  


Mould also puts asthma patients in danger of developing conditions that will worsen their asthma, such as chest infections or colds. Mould produces spores that may be breathed in, leaving people who are allergic to mould spores vulnerable and exposed to getting their asthma symptoms triggered. Small children and the elderly are most likely to be negatively impacted by mould.13

Ideal environmental factors for asthma

Room temperature

The best room temperature can vary depending on the external season and weather. Asthma UK advises keeping an ambient temperature of 17°C in the winter, as cold air can heighten the danger of respiratory infections.14 The variation between the indoor and outdoor temperature should also not be above 8°C, as a difference that is bigger may agitate asthma symptoms.15


The best humidity level is approximately 40-60%, as asthma symptoms tend to be more severe if indoor temperatures are overly humid or dry.15 A consistent temperature at the same level should be kept, alongside with the house being decently heated, in order to avoid an excessive amount of humidity.  Hanging wet clothing on heaters can also raise humidity levels.16

Other factors

Different amounts of pollen are produced at different times of the year. It can therefore be difficult for asthma patients to regulate the level of pollen they are exposed to, but utilising a pollen calendar can prove helpful to identify the expected levels of pollen. Mould spores should additionally be avoided when going on woodland or nature walks.8

Devices to monitor the ideal environmental factors 

Air purifiers or air conditioners are an excellent way to avoid asthma flare-ups and improve indoor air quality, as they clear the air of damaging substances. Air conditioners can also artificially produce the air temperature that you desire within your household if windows or doors are difficult to open.15

Suggestions for asthma relief

If mould is becoming an increasingly concerning problem in your house, then the source of the mould and dampness should be identified. There could be a range of sources indoors, such as condensation from the kitchen, drying clothes within the house, or taking a shower. If the mould is present over a space worth one square metre, then it is important to get in touch with a professional who is able to remove the mould. Extractor fans are useful after a shower or when cooking, and the doors to those rooms should also be closed.13

To prevent the danger of hay fever from pollen causing an asthma attack, nasal sprays and antihistamines are effective. Asthma medications such as the blue reliever inhaler that soothes the muscles of the airways should also be readily accessible.8 In terms of relieving your house of dust mites, consistently washing bedding and cleaning on a continuous basis will be beneficial.10

When to get medical help

If you have asthma, and you find that you are having to use your blue inhaler on more than three occasions over the course of one week, then you should consult a medical professional. If treatment begins quickly, then the danger of a dire asthma attack will be decreased.8 


Overall, although there are recommendations for ambient temperatures and humidity, asthma patients should assess what levels work specifically for them. It is significant to make sure that allergens within the household are kept at a minimum to avoid asthma being triggered where unnecessary. In particular, during the winter months, when asthma patients are particularly susceptible to other illnesses and the majority of the time will be spent at home, a clean environment free of mould and other harmful particles should be maintained. 


  1. Quirt J, Hildebrand KJ, Mazza J, Noya F, Kim H. Asthma. Allergy Asthma Clin Immunol. 2018 Sep 12; Cited Aug 2022. 14(Suppl 2):50. Available from: doi: 10.1186/s13223-018-0279-0. 
  2. Agency for Toxic Substances and Disease Registry. Environmental Triggers of Asthma [Internet]. Cited Aug 2022. Available from:
  3. Asthma UK. Weather as an asthma trigger [Internet]. Cited Aug 2022. Available from:
  4. Asthma and Allergy Foundation of America. Weather Triggers Asthma [Internet]. Cited Aug 2022. Available from:
  5. Hamid Reza Shoraka, Moslem Taheri Soodejani, Omid Abobakri, Narges Khanjani. The Relation between Ambient Temperature and Asthma Exacerbation in Children: A Systematic Review. Journal of Health Lung and Diseases. Jan 2019; Cited Aug 2022. 3(1): 1-9 Available from:
  6. Asthma and Allergy Foundation of America. 3 Ways Humidity Affects Asthma [Internet]. Cited Aug 2022. Available from:
  7. National Asthma Council Australia. Pollen triggers my asthma and allergies [Internet]. Cited Aug 2022. Available from:
  8. Asthma + Lung UK. Pollen [Internet]. Cited Aug 2022. Available from:
  9. Asthma and Allergy Foundation of America. How Does Rain Affect Pollen Levels? [Internet]. Cited Aug 2022. Available from:
  10. Asthma UK. Winter asthma triggers [Internet]. Cited Aug 2022. Available from:
  11. Allergy & Asthma Network. Summer Asthma and Warm Weather [Internet]. Cited Aug 2022. Available from:
  12.  American Lung Association. Dust Mites [Internet]. Cited Aug 2022. Available from:
  13. Asthma UK. Moulds and fungi as asthma triggers [Internet]. Cited Aug 2022. Available from:
  14. Asthma UK. Keeping well in the cold: what you can do [Internet]. Cited Aug 2022. Available from:
  15. Aikin - Air conditioning: for people with asthma - their best friend [Internet]. Cited Aug 2022. Available from:
  16.  Airthings. How humidity damages your home — and how to fight it. Aug 2021; Cited Aug 2022. Available from:
  17. Asthma + Lung UK. Asthma action plans [Internet]. Cited Aug 2022. Available from:
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Marya Waseem

BSc Biomedical Science Student, University of Reading, England
Biomedical Science with Professional Experience student at University of Reading. Currently seeking a placement in research and development for 2023/24.
Klarity Health Medical Writer
English Language and Literature tutor from KS1 to GCSE level.

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