Ventilation

[nicholaw]

Has anyone installed a 'lofty whole home ventilation system' in their home and if so does it actually help with condensation on the walls?

[buildersmate]

I assume you must mean this device?
http://www.breathings...entilation_System.htm
No, I have got one and, no, I don't think it will work.
Logical reasons:
Moisture extraction is best placed close to the source of the water vapour - that means extraction above the hob, and in the shower/bathrooms, and not drying clothes in the house. This gadget is a huge extraction fan that you mount above the landing. It purports to removes stale and (some) moisture-laden air from the house and dumps it in the loftspace.
Condensation on the walls occurs when the warm moist air in the house hits a cold surface. You really need to tackle at the source of the moisture, or increase the temperature in the house or improve the amount of insulation you have (cavities insulated? more fibreglass in the loftspace?, or all of these)
Just dumping water vapour in the loftspace is going to create a problem up there. The vapour really needs to be fed right outside (vented right through to the outside)