Yesterday I mentioned the Ventis heating system and mentioned how it pushes fresh air into a building.

One of the benefits of selling the Keepfresh range of CO2 monitors is that I get a sample unit. So I have monitored the CO2 levels in offices and at home. I did offices first and scoffed at how high the CO2 levels were. But then I went home and monitored them at home.

Some rooms were shockers.

It’s winter. The doors are kept closed. The windows are kept closed. The heating recirculates the air. It reduces the power bill, but I discovered at a cost – no fresh air.

It would be interesting to know if many of the colds and flus that we suffer during winter is because we are locking ourselves up in these crypts of recirculated air. High levels of CO2 will cause drowsiness and head aches, but it is also a really good indicator on how much of our exhaled garbage we are recirculating.

So now we have the windows open a small amount to keep a bit of fresh air coming in. More importantly, on a warm day we make sure that we open all the windows to give the entire house a total turnover in fresh air.

Meanwhile Ventis offer a solution where they are pumping fresh air into the house continually. Not a bad concept. I think I have just given them a plug two days in a row. I may as well go the whole nine-yards and drop the web site (