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Hello all, I am looking for advice on the following. I am in the UK and have a detached house, built in 1998. I have converted one of the upstairs bedrooms into a home cinema. The room is 4.5m x 2.5m (not as big as I wanted) with a built in cupboard and also an alcove. I will be installing a cassette blackout blind for the window. So I don't annoy the neighbours with sound leakage, I shut the window when using the room. As you can imagine, in the recent warm weather, the room gets quite warm especially with the projector blowing out hot air. I've been looking at installing a ventilation system to help maintain a constant temperature and keep the air fresh. At first I got quite excited by the idea of an MVHR system as this would help keep the room warmer in the colder months. I looked at single room MVHR systems, namely Vent-Axia and Blauberg. My budget would stretch to these. Then with some more research I realised I need a summer bypass system in order to keep me cool in the warm weather. Neither the Vent-Axia HR100R or Blauberg Ultra D105-A have a summer bypass option. I don't wish to have a wall mounted system, I have seen these types available. What I would like is just an intake and extract valve fitted within the ceiling. Does anyone know if there is such an MVHR system with summer bypass within a £250 budget? Otherwise, my plan B is to install the valves and then intake fresh air and extract stale air using ducting and inline fans. If this is my only option then is there such a thing as a filter box that I can use on the intake side of things that uses replaceable filters? I've seen that Blauberg do a CleanBox system that looks great, but is over my budget. Anything similar to that? I'm happy to DIY to a certain extent. I was thinking of using a pollen filter and housing from a car as a last resort unless someone does something for this type of situation. The other thing was the control of the inline fans. It would be good to remotely control them and to have speed control - so I can trickle vent during the winter and then go full speed in the warm weather. Is this possible with a limited budget? I have updated the extractor fans in my bathroom and en-suite and connected these via smart plugs so I can voice control their operation. I can see me doing the same for the cinema room, but this won't give me speed control. I'd welcome any thoughts and suggestions on what others have done to achieve the same goal? Thanks!

Having picked up a Titon HRV1.25Q Plus Eco for a price that was too good to pass on I now find myself with slightly less controllability than the Xpelair Natural Air 180 unit previously planned for. Specifically, the Titon's humidity-controlled boost function is based on an absolute threshold rather than rate-of-rise, and its summer bypass has fixed thresholds that cannot be adjusted at all. All along I have been planning on employing a Pi Zero to monitor system temperatures and control boost and setback flows, and so I have decided now to bring humidity-controlled boost and summer bypass within its scope also. The former can piggyback the existing boost input but with the bypass being internally controlled I have had to pinpoint on the control PCB where to tap into to influence (actually take over) this function. What I would like the panel's input on is the control logic for these features in case there's something I haven't considered (or just got plain wrong!). Humidity-Controlled Boost I am attracted to rate-of-rise control on the assumption that it'll ride out seasonal variations better whilst also being more sensitive and reactive to genuine need. To achieve this control I think I need to consider: Inputs: Extract (i.e. from rooms) humidity Outputs: Boost Settings: Rate-of-rise threshold ($rateofrise), time period ($timeperiod), when to turn off again ($deactivatethreshold) Control Logic: 1) If the humidity rise over $timeperiod exceeds $rateofrise activate the boost. 2) Continue with boost until the humidity falls to $deactivatethreshold. This sounds reasonable I think? What should $deactivatethreshold be though? The pre-rise humidity value, or at least something near it in case the background humidity has risen slightly in the meantime? My starting figures are likely to be something like 5% for $rateofrise and 5 minutes for $timeperiod. Incidentally, I was planning on taking measurement every five minutes so that'll be the minimum boost time period. Summer Bypass From what I have read it seems that summer bypass works better in theory than in practice but I like the idea of it and given the Titon has the capability I may as well make use it. As per the previous process I think I need to consider: Inputs: Extract (i.e. from rooms) temperature, Intake (i.e. from outside) temperature, time of day(?) Outputs: Summer bypass, boost(?) Settings: Room temperature threshold ($roomtempthreshold), Outside temperature minimum ($outsidetempmin), quiet time ($quiettime), when to disable bypass again ($deactivatethreshold) Control Logic: 1) If the temperature of the air being extracted from the rooms exceeds $roomtempthreshold and the outside temperature is at least $outsidetempmin then activate the summer bypass (unless the outside temperature exceeds the room temperature). 2) Additionally (and optionally?), with the bypass active also activate boost unless we are within $quiettime (e.g. at night). 3) Continue with the bypass active (and, optionally, boost) until the room temperature falls below the $deactivatethreshold. Typical figures might be 22C for $roomtempthreshold, 15C for $outsidetempmin, 2300-0700 for $quiettime and 18C for $deactivatethreshold. Thanks for reading this far. Should I be considering a different approaches? Is there anything I should/could consider?