Internal Air Quality

As part of my Retrofit Academy PAS2035 Retrofit Coordinator course, I’ve learned a great deal about the Whole Building Approach, the importance of moisture management and ventilation. These things not only affect the immediate risks of condensation and mould, but also the internal air quality (IAQ) within buildings.

We instinctively know when rooms feel stuffy or damp. As a hay fever sufferer (and other allergies), I wondered what our home’s IAQ was actually like. I already know our 1960s home is under-ventilated by modern standards, lacking the optimum number of trickle vents and intermittent extracts. I purchased an inexpensive air quality meter to show the overall Good/Fair/Poor IAQ rating along with readings for carbon dioxide ppm, air temperature and humidity. I have been using it as I work from home or just sit and watch TV in the evenings.

What is considered good a target? CO2 should ideally be kept below 900-1000ppm for good IAQ. Relative humidity should be in the comfortable range of 35-65%, and is directly linked to temperature which should be kept below 25degC to avoid overheating (using the Passivhaus definition).

I have found simply being in a room without an open window will raise the reading from 600 to over 1000 in an hour, dropping the rating from Good to Fair. Opening a window brings the level back down pretty quickly. On cooler evenings where we don’t want windows open I’ve seen the CO2 rise to nearly 1500 ppm. No wonder we fall asleep in front of the TV!

For anyone regularly working from home, have you considered what your indoor air quality is like and how it might affect your health, productivity and ability to focus all day?

I’m working my way around our house understanding what is happening and how remedial measures could help. Although not scientific, it does show the power of data for retrofit works. Understanding the problem first generates solutions that are appropriate and more likely to deliver an improvement. Why guess? Measure!