We have the inline heating system with our HRV and it is excellent, however, since putting the HRV in, we have only used it once or twice to give it a whirl to see how it is, it is excellent.. however we haven't needed to use it, saving it for a real cold snap through winter if need be, just having the HRV itself running warms the house, more so than what it used to be without the system, as we no longer have that damp cold feeling in the place. I tell you how you really notice, since coming in late at night from being out or through a real cold day, you go into your home and warmth hits you, this is without the heating option of HRV being used, it is just the normal system running, all that cold damp air no longer exists and the house is so much more comfy..... No mould... no clogged up feeling, air is fresh... walls and window sills are dry... definately if you can afford it, it is money well spent... DVS, HRV.. anything similar.