Appreciate it was winter when you posted this, but we've got the same in a a bungalow. I was staggered it was still working. We've been quoted around £5k for a vented system (rather than combi as its too big a bungalow to make that vfm and advantageous). I don't really understand heating systems either but the air/storage is difficult to control especially if you're out at work - you have to plan ahead and guess how warm you want it later, don't you? We knew we were buying a do-er upper and the heating was going to be done. I think £5k is a good investment and will more than pay us back in any future maintenance of the air system and ultimately through the end property value. On this one occasion, I would go with convention.m hope you've been happy with your decision if you've done it already.

I'm no expert but I have a theory. If the chimney is sealed at the top perhaps warm air from the house is going up the vent and finding nowhere to go is coming back down and bringing any residual soot on the chimney lining with it. Quite common with houses pre-1965 I think and a problem that never really goes away. Having the chimney swept might help tho.

They are a very good idea depending on your house, style, and needs, if not the most attractive solutions. I have however seen windows with recessed and colour matched trickle vents - so maybe you need to speak to your supplier of other suppliers. You haven't mentioned the age of your house - if you are in a period property you must have good ventilation, especially if you are getting double glazing. Although I have experienced newer- build property in desperate need of trickle vents because there is no ventilation! Otherwise you will get condensation and then damp. If you seal up all draughts in your house you will end up living in a sweat box. Also, check your insurance - having a window open, even if locked open a crack, will often invalid insurance. Trickle vents avoid this. Also note that trickle vents can be opened and closed, and also retro-fitted. A friend had trickle vents fitted and it solved their damp issues. Consider your window dressing - if you are hanging blinds they may hide the trickle vents. I have trickle vents in new uPVC windows, and sash windows in other rooms but as I have floor vents and stripped wood floorboards my house is well ventilated so I don't worry too much.

Walls are not insulated. Would assume I should make sure exterior vents are kept so moisture can escape from the cavity? There's been issues with walls sucking up groundwater, so to let that moisture escape somewhere. I'm going to have have to insert some damp proofing rods in several places. Cheers!