What causes dampness and condensation in your house?
- Lack of adequate heating and/or ventilation.
- Water coming in from the outside through leakage, seepage, persistant absortion.
- Rising damp – dampness from the ground rising up into the building fabric.
- High levels of moisture/water vapour being produced inside the house.
Why is it important to keep a house dry as well as warm?
Moulds and other fungi can grow in damp homes, particularly in areas where there is restricted ventilation, such as inside cupboards and wardrobes. These microscopic organisms release tiny lightweight spores which can be inhaled. If you smell a musty odour or see mould, you have a problem.
Moulds can produce adverse health affects, such as respiratory problems, nasal and sinus congestion, plus skin rashes and irritation. A damp mouldy house is bad for people’s health so it is important to keep your house dry to prevent mould growth.
Humidity
Air contains moisture – this is called humidity. The higher the temperature of the air the more water it is able to hold. Air at 20°C can hold a lot more moisture than air at 10°C. The term ‘relative humidity’ describes how much moisture air contains at a given temperature. 100% relative
Humidity means the air is holding as much moisture as it can at that temperature.
The more humid the air is in your house, the more energy it takes to warm your house because it is also warming the water in the air. This means it will be more expensive to heat!
A good range of indoor humidity for comfort and health is between 30-60% during cooler months of the year. Mould is likely to occur if the relative humidity indoors is 70% or more for long periods of time. Keeping humidity levels under 50% also helps to minimise or control dust mites. But it is also possible to live in a house that is too dry! Humidity levels below about 30% lead to dry skin and nasal passages, increasing the potential for respiratory illnesses.
It is worth buying a low cost humidity meter from a hardware store and track how humid the air in your house is. You might be surprised at how quickly it can change, from morning to night, from room to room, and as the weather changes.
Humidity and condensation
When the humidity is high inside a house and it is cold outside the water vapour condenses on cold surfaces. The following areas might have problems with condensation and dampness:
- Cold surfaces such as mirrors, single glazed windows, and metal window frames (‘crying’ windows)
- Kitchens and bathrooms
- Solid, uninsulated walls of unheated rooms
- Cold corners in unheated rooms, particularly where outside walls meet
- Wardrobes, cupboards.
Humid air and condensation can also be generated by things people do in their homes on a daily basis.
Sources of Humidity and damp
Source of humidity/moisture | Litres of water vapour |
Cooking | Up to 3 litres per day |
Clothes washing | 0.5 litres per wash |
Showers and baths | 1.5 litres per person |
Washing dishes | Up to 1 litres per day |
Un-vented clothes drying | 5.0 litres per load |
Unflued gas heater | 0.5-1.0 litre per hour of use |
Breathing, active adult | 0.2 litres an hour per person |
Breathing, adult asleep | 0.02 litres an hour per person |
Pot plants | A high number of pot plants or if you frequently water them will increase humidity in your house |
How to keep your house dry and avoid condensation
There are lots of things YOU can do to minimise dampness and condensation in your house.
Four key actions:
- Reduce the amount of moisture produced in the home
- Provide ventilation, particularly in moisture-prone areas
- Increase heating to raise the temperature of the air and the cold surfaces
- Insulate the building to warm up cold surfaces and keep the heat in
How Can Solarventi help the above
- SolarVenti forces warm air into the home whenever the sun shines, ventilation is vastly improved, if sized properly the air in a room can be changed every two hours.
- SolarVento also increases air temperature, by providing an addition heat source, with no running costs and no additional moisture.
Low cost options
- On dry days open some windows to allow humid air to ventilate out of the house. It is better to open a few windows a little throughout the whole house. This helps the air to move through the house. One window open wide in one room may not be as effective. Try to do this as often as possible (2-3 times a week), but keep windows closed on wet days as damp air may increase indoor humidity.
- Keep lids on your pots and pans when you cook – simmer rather than boil hard.
- Keep the doors to the bathroom and kitchen closed when you are bathing or cooking.
- Use thermal or lined curtains, keeping them open in the day and closed before dusk. This will capture the free heat from the sun and help to lift indoor temperatures.
- Always wipe excess moisture from windows – if you don’t the moisture will collect on the frame which may start to rot. It may also re-evaporate during the day, raising humidity levels and making condensation worse when the room cools down.
- Limit the number of pot plants in your house.
- Install temporary plastic window insulation kits on your windows for the cooler months of the year.
- Keep furniture away from outside walls to allow air circulation. Cool areas behind furniture will be high humidity areas conducive to mould growth.
Heating
- On cold days try to keep indoor temperatures at least 20°C.
- Try not to use a portable gas heater. They create high levels of humidity and are expensive to run. They also release harmful gases into the air.
- Where possible install efficient heating, suitable for each of the rooms being heated
- Install a heater in your bathroom.
- Dehumidifiers extract moisture from the air and can help reduce humidity. However they do not tend to solve underlying problems of moisture getting into your house, excess moisture production in the home, and lack of ventilation and heating.
Drying clothes
- Wherever possible, dry your clothes outside.
- If you use a clothes dryer, make sure that it is vented outside.
- If you must dry your clothes on a clothes rack inside, do this in a well ventilated room with doors closed to the rest of the house.
SolarVenti Solar air collector is suitable for holiday houses, family houses, work-shops, garages, cellars, storerooms, boats, caravans, annexes, museums and much, more..
- No running costs
- No emmisions
- Perfect for Solar 'off grid' installations
- Easy to install