In this reader Q&A for the Irish Examiner related to windows and external insulation was published in October, 2025.
Q. Hi Kieran
About 18 months ago we replaced our windows and got the outside insulated. I open the windows every day. Yet clothes are damp coming out of the wardrobes. Is this normal?
Thanks
Noreen Kelly
A. Hi Noreen
Thank you for your question. It’s certainly great to hear that you have invested in your home and, in particular, the external envelope. I am assuming that you have fitted new double or perhaps triple glazed windows. These along with the new external insulation layer on your external walls should greatly improve the thermal capacity or the insulation quality of your home. One of the benefits of external insulation of course is that it allows you to add a considerable amount of insulation to your home with minimal disruption, whilst keeping your blockwork external walls as a heat store, similar to a storage heater. (They take longer to heat but retain heat for longer) I would also advise checking to ensure you also have adequate insulation in your attic too 300-400mm of modern quilt insulation is advised.
It is disappointing to hear that you are noticing that the clothes in your wardrobe are damp. What this likely means is that there is not quite enough air circulation in your home but let’s dig a little deeper here..
As you have now installed new windows, I am not sure if you have installed airtightness tapes around the edges. I am also unsure if you have had window vents fitted. It would appear that the house needs to breathe more particularly at night when people are sleeping in these rooms as your old windows likely were allowing some level of air passage due to their age, and the new windows are likely better sealed. This, along with the fact that they may not have vents fitted and may be sealed at the edges, means there is less air being circulated in your home and any moisture can build up, particularly on absorbent fabrics as you have as you have indicated.
Believe it or not, this is now a very common occurrence when existing houses are renovated as their air circulation level needs to be rebalanced to a new optimum level. Your existing house likely had little ventilation designed into it and unbeknowingly relied on gaps in the original building fabric which may very well have been sealed as you applied new modern finishes.
What I would suggest is seeking advice from a ventilation specialist company. It may be that you need some form of mechanical ventilation in your house which will manage the moisture laden air and ensure it is removed as it is generated. Typically, the rooms that generate most moisture are ensuites and bathrooms that contain showers. Most showers have a local extraction vent fitted but when houses are renovated and draughts reduced, these shower vents have to work harder and they often need further assistance from a new local mechanical ventilation unit.
These ventilation units are now very effective both in terms of their performance and value for money and they can be fitted locally, where you are experiencing these issues, A ventilation supplier can advise you on the optimum placement of these units in your home and it may be that you will need window vents fitted. If your windows are PVC then it is likely that your window company can retrofit these vents, if not you may need to fit new wall vents to work with the mechanical ventilation system. The principal is that the mechanical ventilation system detects moisture or carbon dioxide build up and it begins to extract this moist air and expel through a new vent in your wall whilst bringing in fresh replacement air though your local window vents. This also helps with general air refreshment locally during this regular process. These mechanical ventilation units are generally very quiet but best to seek the advice from your supplier on the particular unit they suggest. Hopefully once this is fitted you will sleep soundly and have a fresh outfit for the day ahead.
