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On this page
  1. The short answer
  2. Why it matters
  3. What humidity control does not do
  4. Room by room
  5. Monitor your own home
  6. Dew point calculator
  7. Printable cheat sheet
  8. Questions people ask
  9. References
  10. Cite this page

The short answer, with the numbers behind it#

Relative humidity (RH) is how full the air is of water vapour, as a percentage of the most it could hold at that temperature. Four numbers do most of the work.

  • 40-60%

    The healthy band. Reviews of the health literature find most of the harm from damp and dry air is minimised between 40% and 60% indoors.[1][2]

  • ~50%

    Where dust mites struggle. Mite populations are smallest below about 50%, and very few can grow below about 45%. In laboratory tests, keeping the daily average under 50% restricted their growth even when it rose above for a few hours.[1][3][4]

  • 60%+

    Where most mould species can start in room air. Most fungi cannot grow unless relative humidity exceeds 60%. Keeping indoor humidity below 60% is standard advice.[1][16]

  • 75-80%

    Mould on a surface. Mould on walls needs the surface to stay around 75-80% or more, typically for weeks. Cold walls reach that even when the room air reads lower.[12][13]

Dryzen holds a home at roughly 50-55%. That is a product setting we chose to sit inside the 40-60% band, below the line at which mould can grow in room air and close to the line below which mites struggle. The source evidence supports the band, not that exact setting, so treat 50-55% as our design target and 40-60% as the healthy range.

One more honest point before the detail: the figure on the screen is not the goal. Persistent dampness is. The World Health Organization advises that the most important way to avoid health effects is to prevent persistent dampness and mould growth on indoor surfaces.[8] Humidity is how you see it coming.

Why it matters#

Dust mites#

House dust mites take in water from humid air. They keep their water balance when the air is at about 65% or above, and lose water to the air when it falls below about 55%.[3] That is why a drier home is a less welcoming one: in laboratory work, populations held at 75% humidity for four to eight hours a day (and 35% the rest) grew about 97-98% less than populations kept at a constant 75%.[4]

This does not mean mites vanish. Sources say populations cannot grow, not that every mite dies, and allergen already in the dust stays there. And lowering mite numbers has not been shown to improve asthma (see the box below).

Mould#

Mould needs moisture on a surface, not just in the air. A UK study validated against 36 dwellings found that a surface in equilibrium with air above 80% relative humidity for a month or longer is enough for mould to germinate on common finishes such as emulsion-painted plaster or wallpaper.[12] Finnish building research puts the critical level for mould on wood at roughly 75-80%, depending on temperature and how long it lasts.[13] There is no single magic number: thresholds shift with the material, the species, the temperature and the duration.

This is why mould appears first on cold external walls, behind wardrobes and in the corners of poorly ventilated rooms. The air in the middle of the room may read 55%, while the wall surface a few centimetres away, being colder, sits well above 80%. The calculator further down shows that effect with your own numbers.

UK government guidance describes condensation as the most common form of damp, notes that damp and mould mainly affect the airways and lungs, and puts ventilation (extractor fans, trickle vents) at the centre of prevention.[14] Controlling moisture is what stops mould returning; existing mould has to be cleaned off with a suitable product first.[14][16]

Health#

A large body of epidemiological research links indoor damp and mould with asthma, wheeze, coughs and respiratory infections, and the evidence strongly suggests damp and mould can worsen asthma in children.[9] Repairing damp and mould-damaged homes has been shown, in a Cochrane review, to reduce wheeze and rhinitis in adults.[10] A trial in children's homes found that remediation aimed at moisture sources cut asthma symptom days; the reduction in exacerbations was not statistically significant on an intention-to-treat basis.[11] In every one of those studies the intervention was fixing the building, not running a machine on its own.

If you rent from a social landlord in England, Awaab's Law has applied since 27 October 2025 and sets deadlines for investigating significant damp and mould hazards. It does not apply to private homeowners.[15]

Air that is too dry#

The goal is a comfortable middle, not as dry as possible. Low indoor humidity dries out the eyes and airways and makes the lining of the airways less effective at clearing irritants.[2] In laboratory and animal work, influenza persisted longer and disease was worse in low humidity.[18][19] A systematic review of 24 studies concluded that adapting humidity to limit virus transmission is complex.[17] A nursery-school trial found fewer influenza-positive samples in humidified rooms, but the authors say the cause is unknown,[20] and a Cochrane review found that humidifying workplace and school air may have little to no effect on dryness symptoms.[21] None of this says a dehumidifier prevents colds or flu. It says: avoid the extremes, in both directions.

What humidity control does not do#

Read this before you buy anything

  • It does not treat or cure asthma or allergy. Cochrane reviews of dust mite control and of dehumidification found no clear clinical benefit.[5][7] A whole-house dehumidification study cut mite allergen but not symptoms.[3] Some researchers argue those trials tested minimal interventions and that the question is still open.[6] We claim only that lower humidity makes a home less hospitable to mites and mould.
  • It does not remove mould that is already there. Clean it off hard surfaces with a suitable product and let it dry fully; government guidance prefers mould and mildew products to bleach. Then fix the moisture so it does not come back.[14][16]
  • It does not fix a leak or rising damp. Leaks, penetrating damp and rising damp are structural moisture sources. They need a repair, not a dehumidifier.
  • It does not get rid of bed bugs or spiders. A 2024 laboratory study found bed bugs do less well at constant 50% than at 90% humidity, but that was lab rearing, not a home, and extension guidance says changing the environment alone is not enough.[30][31] We found no evidence at all that humidity control controls spiders.
  • It does not clear a flea problem. Flea larvae need humid pockets (extension services cite at least 75%), so drier air is less welcoming, but fleas must be treated directly.[22][23]
  • It does not replace ventilation, heating or insulation. Moisture control is a system: source, ventilation, warmth and, where needed, dehumidification.[14]

There are pests that do benefit when a damp home dries out, covered honestly in the questions below: silverfish and booklice most clearly, woodlice and fleas to a lesser degree.

Room by room#

The evidence supports one healthy band for the home as a whole, so every room aims for 40-60%. What differs is how moisture gets into each room and where it settles. Short spikes in a bathroom or kitchen are normal. What matters is whether the reading falls back to the rest of the house, and whether anything stays cold and damp for weeks.[4][12]

Typical pitfalls and what to do, by room
RoomAim forTypical pitfallWhat to check or do
Bedroom40-60%, nearer 50% to discourage mites[1][3]Breathing overnight with doors and windows shut; wardrobes and beds pushed against cold external walls.Read the hygrometer when you wake, before opening a window. Keep a gap behind furniture on outside walls.
BathroomSpikes are normal. Judge how far and how fast it falls back.Showers release moisture quickly; with the door open and no fan it travels through the house.Use the extractor fan, keep the door closed during and after, wipe condensation from tiles and windows.[14]
KitchenSpikes are normal while cooking.Boiling and steaming without lids or an extractor vented outside.Cook with lids on, run the extractor, check the reading again an hour after you finish.
Utility or laundry40-60%Drying washing indoors; a tumble dryer that is not vented outside.Dry laundry in a room with an extractor or outdoors where possible; vent the dryer outside.
Loft40-60% and no stainingWarm, moist air from the house reaches cold roof surfaces and condenses there.Look for staining that follows rain (a leak) versus damp that follows cold mornings (condensation).
Cold external walls and cornersThe wall surface matters more than the room reading.Room air reads 50-55% while the wall surface sits above 80% because it is colder.[12][13]Measure the wall temperature with a surface thermometer and use the calculator.

How to monitor your own home for humidity#

You do not need a specialist. A decent hygrometer, a week of consistent readings and a notebook will tell you more about your home than a one-off visit.

1. Choose a hygrometer#

A hygrometer measures relative humidity. Most also show temperature, which you need to make sense of the reading. These are the main kinds.

Hygrometer types compared
TypeRealistic accuracyGood forWatch out for
Digital thermo-hygrometerSpecifications commonly quote about ±2 to ±5 %RHMost homes. Cheap, quick to settle, shows temperature too.Cheap units can be several points out. Check with the salt test below.
Analogue dialUsually the least accurate and slowest to settleA rough idea at a glance.Drift over time. Not a good basis for decisions.
Smart sensor (Wi-Fi or Bluetooth)Similar sensor accuracy to a digital unitHistory graphs, spotting overnight patterns, phone alerts.The app does not make the sensor more accurate. Still check it.
Calibrated instrumentTypically ±2 %RH or better, with a calibration certificateLandlords, surveyors and anyone who needs a number they can defend.Costs more. Overkill for most households.
Moisture meter (pin or pinless)Reads material moisture, not air humidityPinpointing which wall or timber is wet.[14]It tells you where it is wet, not whether the room air is too humid. Use both.

Accuracy figures above are what manufacturers typically state, not results from the references. Check the specification of the model you buy. Useful features: a display of both temperature and humidity, a minimum and maximum memory, one-percent resolution and a replaceable battery. An infrared surface thermometer is a cheap addition that lets you measure cold walls for the calculator below.

2. Where to put it#

  • On an inside wall, not an outside wall or in a corner where air stagnates.
  • At 1 to 1.5 metres high, roughly where you breathe, not on the floor or a window sill.
  • Away from the kettle, cooker, shower, radiator, window and direct sun, which all give false spikes.
  • One per floor, plus one in the room you worry about most. Humidity varies between rooms, and the worst room is the one that matters.
  • Leave it 30 minutes after moving it before you trust the reading.

3. Check it with the salt test#

A sealed space above a saturated salt solution settles at a fixed humidity. For common salt (sodium chloride) that is about 75% RH, and it barely changes with temperature: 75.7% at 10 °C, 75.5% at 20 °C, 75.3% at 25 °C and 75.1% at 30 °C, according to the US National Bureau of Standards compilation.[32] Laboratories use this method to calibrate hygrometers. You can use the same trick at home.

  1. Make a salt slush. In a jar lid or saucer, mix a few tablespoons of ordinary table salt with just enough water to make a wet paste, like damp sand. You should see undissolved salt, with no standing puddle.
  2. Seal it in with the hygrometer. Put the lid and the hygrometer into an airtight tub or a resealable freezer bag, with the hygrometer not touching the paste. Close it.
  3. Leave it alone. Keep it at a steady room temperature, out of sun, for at least 8 hours. Overnight is easiest. If the reading is still moving, give it longer.
  4. Read it without opening the container. A perfect hygrometer shows about 75%.
  5. Work out the correction. Correction = 75 minus the reading. If it shows 79%, it reads 4 points high, so subtract 4 from everyday readings. If it shows 72%, add 3.

How far to trust the result

This is a one-point check at the damp end of the scale, where mould decisions are made. A unit that passes at 75% is probably fine through the range, but it is not proof. If it is out by more than about 5 points, or the reading will not settle, replace it. Do not let the paste touch the sensor.

4. Take readings#

  • Twice a day, at the same times. Morning, when you wake and before opening windows, and evening, before bed. Dust mites respond to the daily average, so a single reading can mislead.[4]
  • Log it for at least a week in the table on the cheat sheet. Write down the time, room, temperature and humidity, plus anything unusual: showers, cooking, washing drying, heating on or off, weather.
  • Look for the baseline and the spikes. The baseline is what the room settles at overnight. Spikes with a cause are fine. A baseline that stays high is the signal.
  • Repeat in a different season. Winter, with cold surfaces and closed windows, is when condensation shows up.

5. What the numbers mean#

Reading your baseline (the overnight or all-day level, not a short spike)
BaselineWhat it meansWhat to do
Under 40%Dry. Can irritate eyes and airways.[2]No need to dehumidify. Check you are not over-heating or over-ventilating.
40-50%Healthy, and hard for dust mites.[1][3]Nothing. Keep logging now and then.
50-60%Healthy, upper half. Mites can start to grow near and above 50%.Fine for most homes. Check cold walls and the worst room.
60-70%Damp side. Most fungi can grow above 60%.[1]Work out why: drying washing, no extraction, cold surfaces. Use the calculator.
Over 70%, sustainedCold surfaces are likely to be wet or close to it. Mould needs surfaces held around 75-80% for weeks.[12][13]Act now: find the source, ventilate, heat evenly. If there is no obvious cause, suspect a leak.

6. Early signs, and a decision flow#

Numbers are one signal. Your eyes and nose give earlier ones:

  • Condensation on windows in the morning, or water pooling on the sill. Note when it appears: after showers and cooking is ordinary, but in a bedroom at sunrise it points to overnight moisture.
  • Cold corners, behind wardrobes and along outside walls that feel clammy or show speckles or shadowing.
  • A musty smell in a room or cupboard, especially when you first open the door.
  • Peeling paint, lifting wallpaper, black spots on sealant around windows and in showers.

Work through these in order.

  1. Is there a stain or wet patch that changes with rain, follows a pipe, or sits under a bathroom, roof or gutter?

    Yes

    Suspect a leak or penetrating damp. Find and repair the source before anything else. A dehumidifier will not fix it.

    No

    Go to check 2.

  2. Is it a film of water on windows or cold walls, mostly in the morning or after showers and cooking, sometimes with specks of mould or a musty smell?

    Yes

    This looks like condensation, the most common form of damp.[14] Go to check 3.

    No

    Log readings for a week anyway. If nothing is high, you are fine.

  3. Does your log show a baseline above 60%, or does the calculator put your cold wall near or above 80% at its surface?

    Yes

    Reduce moisture at source, ventilate, heat the room evenly, and consider dehumidification to hold the level down. Go to check 4.

    No

    Habits are probably the cause: drying washing indoors, no extraction. Fix those and re-check in a week.

  4. Is there visible mould already?

    Yes

    Clean hard surfaces with a mould and mildew product, let them dry fully, then fix the moisture so it does not return.[14][16] If it is widespread, keeps coming back, or anyone in the home has breathing problems, get advice.

    No

    Good. Keep the humidity down so it does not start.

7. When to call a professional, or when it is a leak#

  • Damp patches that do not change with the weather or the heating, tide marks, or plaster that blows or crumbles.
  • Readings that stay high even after you have removed obvious sources and ventilated.
  • A stain that grows after rain, or one that appears below a bath, shower or roof.
  • Mould that covers a large area or returns after cleaning.

Start with a plumber, roofer or damp surveyor as the evidence suggests, and tell your landlord in writing if you rent. Tenants of social landlords in England have deadlines in their favour under Awaab's Law.[15]

Monitoring that comes with a Dryzen system

Every Dryzen system includes a smart app with temperature and humidity monitoring. It needs a 2.4GHz Wi-Fi network and an internet connection. Dryzen's yearly Gold Pack membership also includes a free humidity monitoring plan, and Dryzen alerts members if there are any issues with their home or the dehumidifier.

Dew point and condensation calculator#

The dew point is the surface temperature at which the water in your air starts to condense. Any surface colder than it gets wet. Put in the room temperature and humidity from your hygrometer. If you can measure a cold wall or window with a surface thermometer, add that too.

Check your own numbers

This calculator needs JavaScript. The table below the box gives the same answers for common conditions.

Measured with a surface thermometer.

It is an estimate. It uses the Magnus approximation, dew point = b·γ / (a − γ) where γ = a·T / (b + T) + ln(RH / 100), with a = 17.62 and b = 243.12 °C (Sonntag 1990 constants, stated accurate to about 0.35 °C between -45 and 60 °C).[33] Your hygrometer, the surface thermometer and the materials in your walls all add error. The 80% surface line is the level around which mould can begin when held for weeks on common finishes,[12][13] not a guarantee either way. Nothing is sent anywhere; the calculation runs in your browser.

Dew point (°C) for common room conditions (no JavaScript needed)
Room temperature40% RH50% RH55% RH60% RH70% RH
16 °C2.45.67.08.210.5
18 °C4.27.48.810.112.4
20 °C6.09.310.712.014.4
22 °C7.811.112.513.916.3
Surface temperature (°C) below which the surface exceeds 80% RH, by room temperature and humidity
Room temperature40% RH50% RH55% RH60% RH70% RH
16 °C5.68.810.311.613.9
18 °C7.410.712.213.515.9
20 °C9.312.614.115.417.9
22 °C11.114.516.017.419.8

Printable cheat sheet#

One A4 page: the range, room targets, a weekly log and the salt test. Print this page from your browser and only the sheet prints, or download the PDF.

Download the PDF

Healthy Home Humidity Cheat Sheet

Too dryunder 40%
Healthy40-60%
Mould and dust mite zoneover 60%

Under 40%: irritates eyes and airways.

40-60%: the healthy band. Mites struggle under about 50%.

Over 60%: mould can grow in room air. Wall mould needs the surface at about 75-80% for weeks.

Room targets (all 40-60%)

RoomWatch for
BedroomOvernight build-up; aim near 50%
BathroomFast spike; fan on, door shut
KitchenCooking spikes; lids on, extractor
UtilityIndoor drying; vent the dryer
LoftCold surfaces; staining
Cold outside wallsSurface can be damp when the room reads fine

Salt test (check your hygrometer)

  1. Mix table salt with a little water to a wet paste in a lid.
  2. Seal the lid and hygrometer in an airtight tub, not touching.
  3. Leave 8 hours or overnight at steady room temperature.
  4. A perfect hygrometer reads about 75%.
  5. Correction = 75 minus your reading. Apply it to every reading.

Place it

Inside wall, 1 to 1.5 m high, away from kettle, shower, radiator, window and sun. One per floor plus your worst room.

Read your baseline (overnight or all-day level)

BaselineWhat to do
Under 40%Dry. No dehumidifying; check heating and ventilation.
40-60%Healthy. Keep logging now and then.
60-70%Damp side. Find the moisture source; check cold walls.
Over 70%, sustainedAct now: source, ventilation, even heat. Suspect a leak if no cause.

Early signs (check in order)

  1. Stain that follows rain, a pipe or a roof: suspect a leak. Repair it first.
  2. Morning condensation, clammy cold corners, musty smell: condensation. Log a week.
  3. Clean visible mould from hard surfaces with a mould and mildew product, then fix the moisture.
  4. Widespread or returning mould, or breathing problems at home: get advice.

Weekly log (twice a day, same times)

DayTimeRoom°C% RHNotes (shower, washing, weather)
Mon
Tue
Wed
Thu
Fri
Sat
Sun

Baseline over 60% for days, or wet windows and cold walls? Find the source, ventilate, heat evenly. A dehumidifier does not fix leaks or remove existing mould. Sources and the dew point calculator: dryzen.co.uk/humidity-guide/ (last reviewed 5 October 2026).

Questions people ask#

What humidity should my home be?

Aim for 40-60% relative humidity, and nearer 50% if dust mites and mould are your concern. Health reviews find most harm from damp and dry air is minimised in that band.[1][2] Below about 40% the air can irritate eyes and airways, and above 60% most mould species can grow and mites thrive.[1] Dryzen holds roughly 50-55%, which sits inside that band; it is our product setting, not a figure from a health body.

What humidity causes mould?

There is no single number, which is why you should be wary of anyone who gives one. Mould needs a damp surface, typically held at around 75-80% relative humidity or more for weeks, and the threshold shifts with the material, the species and the temperature.[12][13] Cold walls reach that level even when the room air reads lower, so use the calculator with a surface temperature rather than relying on the room reading alone.

What is the best way to measure humidity at home?

Use a digital thermo-hygrometer on an inside wall at 1 to 1.5 metres, away from the kettle, shower, radiator and window, with one per floor plus the worst room. Check it with the salt test, log it twice a day for a week and look at the baseline rather than the spikes. The full method is in the monitoring section.

Can a dehumidifier help with asthma or allergies?

We do not claim it can. Lower humidity makes a home less hospitable to dust mites and mould, but Cochrane reviews of mite control and of dehumidification found no clear clinical benefit for asthma,[5][7] and a whole-house dehumidification study reduced mite allergen without changing symptoms.[3] Repairing damp and mould problems has been shown to reduce wheeze and rhinitis in adults.[10] If you have asthma, speak to your GP or asthma nurse.

Does humidity control help with pests?

For some, yes; for others, no. Silverfish need damp conditions, and university guidance lists dehumidifiers and ventilation among the steps that help discourage them, alongside fixing leaks.[24][25] Booklice feed on mould and do best in humid conditions; guidance advises reducing humidity (below 50%) and moisture,[27][28] and a laboratory study found they died within about one to two weeks at 43-50% humidity.[26] Woodlice need damp conditions and turn up in damp basements and ground floors, so reducing moisture makes a space less attractive to them, though it does not stop them coming in from outside.[29] Flea larvae need humid pockets (extension services cite at least 75%), so drier air is less welcoming, but fleas still need direct treatment.[22][23] Humidity control does not control bed bugs or spiders.

Does a dehumidifier get rid of mould?

No. A dehumidifier does not remove mould that is already growing. Clean it from hard surfaces with a suitable product and let it dry fully; government guidance prefers mould and mildew products to bleach. Then control the moisture so it does not return.[14][16] If the source is a leak or rising damp, that has to be repaired first.

Can my home be too dry?

Yes. Below about 40% the air can dry out eyes and airways.[2][19] That is why the target is a comfortable middle, not as low as possible. A dehumidifier with a humidistat set around 50% will not over-dry a normal home, but running any dehumidifier flat out in an already dry, heated room could.

Is a whole-house dehumidifier worth it?

Only if the cause is airborne moisture and your readings show it. Fix leaks first, then ventilation and heating habits, which government guidance emphasises.[14] If your baseline still sits above 60% or cold walls keep going damp, dehumidification can hold it down. Dryzen's system covers about 150 m² and extracts 12 litres a day per unit, with running costs of about £20 a year, and a smart app with temperature and humidity monitoring included (it needs 2.4GHz Wi-Fi and internet). As well as dehumidifying, the unit does activated carbon filtering of the air, which helps reduce odours, and it can bring in fresh air through a discreet external grille, with an adjustable ratio of fresh and recycled air, both dehumidified and filtered before entering the house. The aim is a healthier indoor environment: humidity held in the healthy band, and fewer of the conditions dust mites and mould need,[1][3][12] with carbon-filtered air; it does not treat or cure any medical condition. Parts and labour are covered for 10 years, with a 1 year compressor warranty. It is for owner-occupied homes with a loft to mount the unit, ducted to the central area and stairway only, and not suitable for rentals unless the landlord authorises it. A free survey will tell you honestly whether it suits you.

References#

Every factual claim on this page rests on one of these sources. Numbers in square brackets in the text match the list. Last reviewed 5 October 2026.

  1. [1]Arundel AV, Sterling EM, Biggin JH, Sterling TD. Indirect health effects of relative humidity in indoor environments. Environ Health Perspect 1986;65:351-361. https://pubmed.ncbi.nlm.nih.gov/3709462/
  2. [2]Wolkoff P, Azuma K, Carrer P. Health, work performance, and risk of infection in office-like environments: the role of indoor temperature, air humidity, and ventilation. Int J Hyg Environ Health 2021;233:113709. https://pubmed.ncbi.nlm.nih.gov/33601136/
  3. [3]Portnoy J, Miller JD, Williams PB, Chew GL, et al. Environmental assessment and exposure control of dust mites: a practice parameter. Ann Allergy Asthma Immunol 2013. https://pmc.ncbi.nlm.nih.gov/articles/PMC5156485/
  4. [4]Arlian LG, Neal JS, Vyszenski-Moher DL. Reducing relative humidity to control the house dust mite Dermatophagoides farinae. J Allergy Clin Immunol 1999;104(4):852-856. https://pubmed.ncbi.nlm.nih.gov/10518832/
  5. [5]Gotzsche PC, Johansen HK. House dust mite control measures for asthma. Cochrane Database Syst Rev 2008;(2):CD001187. (The record carries a note that it predates current Cochrane standards.) https://pubmed.ncbi.nlm.nih.gov/18425868/
  6. [6]van Boven FE, Arends LR, Braunstahl GJ, van Wijk RG. A reintroduction of environmental mite allergen control strategies for asthma treatment and the debate on their effectiveness. Clin Exp Allergy 2019. https://pubmed.ncbi.nlm.nih.gov/30659677/
  7. [7]Singh M, Jaiswal N. Dehumidifiers for chronic asthma. Cochrane Database Syst Rev 2013;(6):CD003563. https://pubmed.ncbi.nlm.nih.gov/23760885/
  8. [8]World Health Organization Regional Office for Europe. WHO guidelines for indoor air quality: dampness and mould. 2009. https://www.who.int/publications/i/item/9789289041683
  9. [9]Mendell MJ, Mirer AG, Cheung K, Tong M, Douwes J. Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence. Environ Health Perspect 2011;119:748-756. https://pubmed.ncbi.nlm.nih.gov/21269928/
  10. [10]Sauni R, Verbeek JH, Uitti J, Jauhiainen M, Kreiss K, Sigsgaard T. Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma. Cochrane Database Syst Rev 2015;(2):CD007897. https://pubmed.ncbi.nlm.nih.gov/25715323/
  11. [11]Kercsmar CM, Dearborn DG, Schluchter M, et al. Reduction in asthma morbidity in children as a result of home remediation aimed at moisture sources. Environ Health Perspect 2006;114:1574-1580. https://pubmed.ncbi.nlm.nih.gov/17035145/
  12. [12]Oreszczyn T, Pretlove SEC. Condensation Targeter II: modelling surface relative humidity to predict mould growth in dwellings. Building Services Engineering Research and Technology 1999;20(3):143-153. http://discovery.ucl.ac.uk/2263/1/2263.pdf
  13. [13]Viitanen H, Ojanen T. Improved model to predict mold growth in building materials. Thermal Performance of the Exterior Envelopes of Whole Buildings X, ASHRAE, 2007. https://web.ornl.gov/sci/buildings/conf-archive/2007%20B10%20papers/162_Viitanen.pdf
  14. [14]MHCLG, DHSC, UKHSA. Damp and mould: understanding and addressing the health risks for rented housing providers. GOV.UK, published 7 September 2023, updated 1 April 2026. https://www.gov.uk/government/publications/damp-and-mould-understanding-and-addressing-the-health-risks-for-rented-housing-providers
  15. [15]MHCLG. Awaab's Law: guidance for social landlords - timeframes for repairs in the social rented sector. GOV.UK. https://www.gov.uk/government/publications/awaabs-law-guidance-for-social-landlords/awaabs-law-guidance-for-social-landlords-timeframes-for-repairs-in-the-social-rented-sector
  16. [16]US Environmental Protection Agency. A Brief Guide to Mold, Moisture, and Your Home. https://www.epa.gov/mold/brief-guide-mold-moisture-and-your-home
  17. [17]Thornton GM, Fleck BA, Dandnayak D, Kroeker E, Zhong L, Hartling L. The impact of HVAC design features on the transmission of viruses, including COVID-19: a systematic review of humidity. PLoS One 2022. https://pubmed.ncbi.nlm.nih.gov/36215321/
  18. [18]Noti JD, Blachere FM, McMillen CM, et al. High humidity leads to loss of infectious influenza virus from simulated coughs. PLoS One 2013;8:e57485. https://pubmed.ncbi.nlm.nih.gov/23460865/
  19. [19]Kudo E, Song E, Yockey LJ, et al. Low ambient humidity impairs barrier function and innate resistance against influenza infection. PNAS 2019. https://pubmed.ncbi.nlm.nih.gov/31085641/
  20. [20]Reiman JM, Das B, Sindberg GM, et al. Humidity as a non-pharmaceutical intervention for influenza A. PLoS One 2018;13:e0204337. https://pubmed.ncbi.nlm.nih.gov/30252890/
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Dryzen (2026). The Healthy Home Humidity Guide. https://dryzen.co.uk/humidity-guide/. Last reviewed 5 October 2026.