Mark-R

Thank you - that's all really helpful, and pause for more thought. I certainly will look at the alternatives you have outlined. I think a system which, once set up, does involve them actively managing it will suit them as they are not technically minded. A couple of other thoughts: Where one has a choice presumably the DDCV units should extract to a sheltered wall? and internally, sited as far from the door a possible. The same would apply to the humidity sensitive wall ventilators? One of the DG units in a bedroom window is misting and will need replacement. If they changed the window surround they could change to a trickle vent type. Its there anything to choose between this and installing a humidity sensitive wall ventilator instead? I've only seen manually adjusted trickle vents but I imagine there might be humidity driven ones (££?) now. Thanks again

I'm new to this blog. I'm lifelong DIYer and had a lot of hands-on involvement with the construction of my current house which is now 6yrs old. This included the installation of a MHVR system (then designed by my builder) based around a Sentinel Kinetic in the basement and using taped 125mm plastic pipework throughout. Whilst balancing seemed rather haphazard when it was commissioned, in terms of performance including quiet, I have absolutely no complaints. This experience has spurred me on to consider self-installing a simple system for my daughter and her family. Their house is a completely different kettle of fish- built in the 1960s of modest size with total floor 105 sqm and ceiling height 2.2m, it has a very large amount of glazing including several floor to ceiling picture windows. Its double glazing is in good nick but there are no trickle vents, has modern external doors (not PH, not that modern) and apart from the extractor over their gas hob, has no ventilation (none in the bathroom). It was never built to a standard approaching air tight. Despite dehumidifiers it is a condensation and mould nightmare. It feels stuffy unless you open the windows, which are large and let all the heat out. The purpose of a system here would be first to help with air quality. I have no expectations of any significant heat recovery. Nevertheless, as a home it is a long term prospect for them, with potential for extension and other improvements, so the greater financial investment seems more reasonable. The only feasible location for the MHVR unit is in part of a large built-in wardrobe in a bedroom that is rarely used. This would allow easy access for maintenance, good access to a suitable external wall for connections to outside and well placed for a radial system of piping to the other rooms via the loft space, and down to the lounge and dining room on the ground floor. The loft is outside the heated envelope but it should be feasible to bury pipework beneath the considerable insulation there. I would be grateful for any general observations from experience. I also had several specific questions: There is a dazzling variety of machines on the market. I am thinking of a Titon HRV1.25 Plus. This seemed a good option in terms of size, cost and not being over-engineered for the job I'm asking it to do. Does anyone have any experience of these units? or would recommend others of similar size/output? It would hang on a wall. Is that a recipe for vibration noise? If so, any tips to mitigate this? Although I expect to use radial 75mm flexible ducting on the input side, because of the layout, I could install larger hard plastic ducting, eg 125mm diameter, on the extract side as it only has to do kitchen and bathroom, which might be cheaper and lead to less work for the machine, so perhaps also quieter. I would balance the system by adjusting the ceiling fittings. Any reason not to use dissimilar ducting on the two sides? The Titon info suggests connecting pipes (125) directly to the machine but I am sure I have read somewhere that it is generally a good idea to use a short length of flexible corrugated duct between the array and MHVR unit for maintenance or replacement. We did this with my own house. I guess I could use BPC Ventilation Flexible Acoustic Silencers here. Have I mis-remembered this recommendation? Thanks.