When I moved into my new house, the first thing I noticed was the dampness. The previous owners had told me already that this was a problem for them and the place was damp no matter how much the heated it ! Straight away I knew what my first plan of action was : Ventilation.
Place place had none whatsoever and with heating cranked up to max, it is no wonder it turned into a fish tank in the winter months.
You can make a pretty effective ventilation system using simple computer fans and some fexible tubes. However due to lack of time -and lack of fans, I got a small simple ventilation kit unit from ebay instead. A simple one is more than enough for a whole small to medium house (mine's a bungalow cottage). Theres absolutely no need for the big industrial size ones some company offer these days. These are overkill and expensive. worse, I've even heard of people having to install humidifiers in the house after installing one of them.
Since it was summer there was no rush for the heat exchanger part so I had time to build it myself. When I enquired, I found out that most were build from coriboard sheets stacked. Luckily, these are easily available (just wait for the next election, referendum and grab ones that were blown down by the wind...)
Cut them in squares -40x40cm is what I did, and stack them so that the ridges of the next layer are perpendicular to the ones of the layer underneath.
Make sure they're glued tight so that no air can go between the layers. I used a spray glue, I can't remember what it was, but it's readily available in most hardware stores.
Once you got a stack of 40 layers or more, I build a case and fitted the stack in a diamond pattern inside the box. Make sure to seal all joints and edges with silicone.
Close it, leave to dry for a few days and there you have it... a perfectly functional heat exchanger.
The idea here is that warm damp inside air comes in from one of the brown tubes, enters the ridges of the stack aligned with the tube. At the same time cold drier air comes from outside into one of the back tubes and enters the stack where the ridges are aligned with it. Since each layer is perpendicular to the other, heat exchanges and you get warm air back into your rooms.
The concept is that the fan extracts warm damp indoor air from places like the kitchen, near the bathroom and let the damp warm air escape. Since the extraction creates a vacuum in the house, cold air is naturaly sucked back into the house from outside. You want to make sure your house is air tight then and have holes in your dry room ceilings (bedroom, office, living room) so that air can come back this way and circulate naturally in the house. Since the air flux exchange heat (without mixing) in the exchanger you're getting warm dry air back in your rooms.
