Why you should calculate the humidity in your property

Humidity levels can have a significant impact on your health as well as the structures and systems in your home. As an example, high humidity can lead to mildew and black mould, while low humidity can exacerbate conditions such as asthma.

What is humidity?

Humidity is the amount of water vapour in the air and is measured as a percentage. A reading of 0% would be completely dry air, without any water vapour at all, while 100% humidity will often look foggy as water vapour condenses out of the air. Both would be extremely unusual in a home.

What is normal humidity in a UK home?

In the UK, as the seasons change the level of humidity outdoors changes too, so the level indoors will also shift. As a result, it’s common for humidity levels to be between 40-60% indoors, with 50-55% being considered ideal. It may surprise you to know that humidity levels outdoors will normally be higher in summer – this is because warm air can hold more water vapour than cold air. Well sealed houses may show the reverse pattern as less fresh air is brought into the home and this can be the start of a problem.

High humidity

Problems caused by high humidity

High humidity can make your home a breeding ground for bacteria and mould. You may notice that food rots quickly, see mildew on the walls or a grey fuzz on soft furnishings. Condensation on walls or windows may also be common. High humidity can also cause health problems as moulds are often allergens and can trigger asthma and breathing issues. Illnesses spread by bacteria or viruses (from the common cold to cholera) find it easier to spread in warm, humid environments.

How to fix high humidity

High humidity is often caused by poor ventilation, and the solution may be as simple as opening the windows regularly. Many human activities, including breathing, bathing, cooking, and washing dishes, clothes and floors, throw moisture into the air which increases the humidity. Using extractor fans in the kitchen and bathroom, drying laundry outdoors and ventilating your home properly may solve the problem. If not, a dehumidifier machine can be purchased which will collect water out of the air. This is particularly effective where the humidity is unavoidable.

Low humidity

Problems caused by low humidity

Low humidity tends to irritate the eyes, nose and throat and can lead to cold or flu-like symptoms. It may also make you more vulnerable to respiratory diseases and can trigger asthma and other respiratory conditions, particularly when paired with cold. It can also make it harder to feel warm, which can be problematic for vulnerable people including babies and the elderly.

How to fix low humidity

The easiest solution to a low humidity problem is to purchase a humidifier. This is a machine designed to increase the amount of water vapour in the air. It will usually have an effective range indicated on the packaging. Most domestic humidifiers have an effective range of 1-3m and are thus ideal for localized use, such as in the bedroom.

If you would like to test the humidity in your home, get in touch or view our Humidity Calculator (Basic) and Humidity Calculator Pro.

About the Author

David Bly

David Bly

Managing Director

David has an Engineering and Management background having been involved with the property damage management industry sector for the last 20 years encompassing the management and dissemination of key reporting protocols. His field-based experience aligns to the creation and production of unique reporting systems that serve to uphold professionalism and transparency of data interpretation for the industries Cornerstone serve.

In addition, his experience aligns to the understanding of damp, condensation and mould related issues in properties combining all industry approved surveying techniques to deliver a bespoke service clients demand.

Cost Calculator
ROI Calculator

Enter data to create cost

Initial investment

1 day course

Annual investment

Costs per Survey / Property per year

Enter data to create cost

Costs per Survey / Property per year

Annual Savings Potential

Return on Investment (and disrepair)