Having lived with MVHR for 9 months I have just completed a DIY active carbon filter as my neighbours just like stinky bonfires too much. Whilst you can easily shut it off when you're at home, it is a horrible surprise to come home to find your home smelling like a bonfire.    So I began to research active carbon filters and found those commercially available ones were stupidly expensive and the cost of replacing the filters was also the best part of an arm too. I began therefore at th