You have probably already tried the small fixes. You have wiped the windowsills, you have opened the windows, and still the walls feel cold and the clothes take days to dry. Now you are looking at dehumidifiers and the numbers mean nothing. This guide will help you pick the right size without getting lost in technical detail.
Why bedroom count is only a rough guide
Most websites tell you to count bedrooms and pick a machine. That is a starting point, but it misses what actually creates moisture in an Irish home. A two bedroom cottage with four people drying washing indoors every day needs more drying power than a four bedroom house with one person who uses a tumble dryer. Think about your actual situation, not just the estate agent's description.
The real questions are:
- How many people live in the house, and how often are they home?
- Do you dry clothes on a rack indoors for months of the year?
- Is the house poorly insulated, with cold walls where condensation gathers?
- Do you heat in short bursts, letting rooms cool down between?
Each of these adds moisture to the air or makes it harder for that moisture to escape.
What the sizes actually mean
Dehumidifiers are sold by how much water they can pull from the air in a day. A small machine might suit a single room with light damp. A larger machine suits a whole house, or a flat where washing dries in the living room and four people shower every morning.
Here is the part many people get wrong. A bigger machine does not run harder or cost more to operate hour for hour. It reaches your chosen humidity level faster, then settles into a quiet idle. A machine that is too small runs constantly without catching up, wearing itself out and leaving you with damp air. In most Irish homes, choosing a bit more capacity than you think you need is the safer bet.
The mistake of buying for one room
Many people buy a small machine for the bedroom with the worst mould, planning to move it around. In practice, this rarely works well. Dehumidifiers are heavy and awkward to carry up stairs. You forget to move it, or you cannot be bothered, or the socket is behind the wardrobe. The damp spreads to other rooms while the machine sits unused.
If your problem is whole house damp, and it usually is in Irish winter, a single properly sized machine in a central spot will do more good than a small one chasing problems from room to room. Position it where air moves freely, often the hallway or landing, and let it work on the whole house.
How to think about your own home
Be honest about your habits. This is not a test you can fail, it is just about matching the machine to the job.
- One or two people, tumble dryer used, house reasonably warm: a smaller capacity machine will probably serve.
- Family home, washing dried indoors, bursts of heating, cold walls: you need more capacity, even if the house is not large.
- Older solid walls, single glazing, or a basement flat: the structure itself releases moisture, so size up.
Also consider where you will empty the water. A machine with a large tank needs less frequent attention. Some can connect to a drain for continuous running, which suits people who are out all day.
What a dehumidifier will not fix
A machine will not dry out rising damp from a failed damp proof course. It will not fix a leaking pipe or a roof that lets rain in. It will not warm up a cold house, though it will make it feel less clammy. If your walls are wet to the touch or you have salt deposits blooming on plaster, you need a builder, not a dehumidifier.
What it will do is remove the moisture that daily life puts into the air, the steam from the kettle, the breath from sleep, the clothes drying on the rack. This stops condensation forming on cold surfaces and gives mould nothing to feed on.
The short answer
For most Irish homes, a larger compressor dehumidifier is the practical choice. If you dry washing indoors, have more than two people living there, or your house is hard to heat, size up without worry. The machine will work less hard, run quieter, and actually solve the problem. Buy for the whole house, not one room, and put it somewhere central with space for air to circulate. Empty the tank daily at first, then less often as the air dries out. You should notice the difference within a few days.