We moved into our dream home in 2009. Situated in Rangiora, North Canterbury - the front part of our house was 100 years old, with an added 3 bedroom wing built in the 1980's. We had a mix of different external cladding, internal lath & plaster, gib, wooden and concrete floors. The house felt damp from the outset. I remember the first power bill, due to a very cold winter and pathetic inset log burner was $800.00 for the month! Our first approach was to install good insulation and a log burner. The next, was the installation of a heat pump in the bedroom (children's wing) of the house. The power bills remained very high and the house (especially the bedrooms) very damp. We had mold growing on the kid's shoes, curtains and carpet. The heat-pump worked continuously through the winter with no real change to the air temperature. All of the kids rooms had single glazed windows and ranch sliders. They were saturated with condensation every morning to the extent of puddles appearing in the slider tracks and carpet and window sills... We then looked at installing double glazed windows for all of the 'problem' areas. This was at a cost of around $12,000.00! I was researching condensation and came across HRV. After a meeting and explanation of the 'physics' behind condensation and their system , we were sold. We had the largest system installed, due to the size and length of our house, and waited with anticipation to see it's supposed miracle cure. When we woke in the morning (middle of winter), we were 'gob-smacked' that there was literally NO condensation on the windows. We thought, maybe we were experiencing a balmy winter morning, so waited with anticipation for the next day... We have had NO condensation on our windows from that day!!! Our heat-pump works far more efficiently because it is now heating dry air. Our power bills have dropped significantly and we have even experienced slight cracks in our walls due to the house 'drying out'. The cost to install our large system was way under half what we would have spent on double glazing, which we understand now, would only have disguised our moisture problem.. If anyone is thinking of installing HRV, just DO it! The thing by far that we have ever spent on our home.