MarkyG82

The building work is done and final touches qre coming to an end (for the new space at least). I thought I'd come back to this for an update and hopefully extract (pun?) some more info from you lot. We now have an Envirovent dmev unit with switched boost in the downstairs WC. Function wise it's really good. Has a mesh filter that so far I've needed to clean once a fortnight. Hoping that will calm down (or could we run it without?). One thing I've noticed is that it's noisy vibrating through the house. I plan to take a look and see if I can fit some sort of gasket between it and the ceiling to isolate it. I was planning on getting the same unit for the ensuite but if the noise is standard for that type (surface mount) I have now been looking at central MeV units to service both upstairs wet rooms. It seems a single unit is similar in price to two dmev units and has the desired benefit of remote location for sound isolation. Am I barking up the right tree? The units I'm looking at (vent axia and Envirovent) both have humidity sensing boost and constant trickle. This should give us the fit and forget function we desire along with the performance. When I first entered this project I didn't appreciate the variety of equipment and this type had passed me by until now. It seems like the perfect solution to my needs. To sum: - Envirovent dmev noisy. Can it be improved? - Is a single MEV better than two dmev units for noise and performance?

Having a read in a few places with your info in mind.... Is the bridging only a requirement for priority hot? If I disable/remove that feature would it modulate as planned even with the 230v motorised valves? We are on cheap night rate with solar diversion get much of the hot water from electric. If we remove the requirement for heating the hot water with the boiler could we get a modulating CH system?

@SimonD thanks for the detailed description. We have weather compensation and priority hot water. How this is achieved I need to find out. The boiler is in now so we are very unlikely to change it. We still have the option of adding smart TRVs if that would help but I suspect not going on your description of how it works above. The plumber assured us that we are getting a modulating system so I am quite annoyed if we are not. It is likely to work and will be better than we had before but one of the reasons to get a new boiler was to go away from relay control with the hive thermostat. I will ask the plumber about the system and get his thoughts. Thanks again.

We are using the room thermostats linked below. They do seem to offer what we expect. I will double check everything though. https://www.worcester-bosch.co.uk/professional/bosch-smart-individual-thermostat

Hi all. Thanks for the pointers. We needed to make a decision quickly so I have chosen the following. I'd appreciate your comments even if you think I've done the wrong thing. Worcester 4000 Zoned via manifold to upstairs, downstairs and new underfloor extension Zones controlled by EasyControl 'stats Priority hot water (fairly sure this will run the boiler as full chat so must be timed outside heating demand) No smart TRVs One of the drivers for the EasyControl system was the 10 year cover when fitted alongside the boiler. The plumber assures me this setup will have full modulation for heating. @JohnMo understood re the requirement for smart control. I am a big nerd and like to have as much of that stuff as possible. As you allude to, this would work just as well once set up whether done with smarts or by a wall control. Doing it on my phone just means I can set it up from the sofa.

@JohnMo Thanks. The boiler selection is based on what the plumber is supplying. I will question that as it may help like you suggest. The smart bit is definitely a want but it will allow us to zone off the upstairs. We like a cold bedroom. I'm happy to set up remote sensing. I already have stuff in the house that will do it. Just needs setting up in home assistant. Are you suggesting that a well set up opentherm boiler will put perform the weather compensation hack as per the plumbers suggestion?

Need to choose one of two system boilers (Worcester 4000 or glow worm energy 7). I want modulation for all the obvious reasons. I also want smart controls so we can add smart TRVs upstairs to zone off the area. Currently not possible to zone it the manual way due to existing plumbing. So I've come up against the issue that neither boilers are opentherm and the thermostats we like (tado or nest) don't modulate without it. Plumber has done some homework and thinks that adding weather compensation will take care of the modulation while allowing the smart controls to call for heat via relay. Two questions to you knowledgeable folk: 1) Is my plumber right? 2) Will the call for water cylinder heating also be affected by said weather compensation? On point 2, the glow worm has a heat setting Dedicated to hot water if that makes a difference. Last question: 3) Do you know of a smart thermostat system (with TRVs) that can natively modulate central heating output using the above boilers? Thanks

@BotusBuild thanks. I think I will put effort into the insulation and ceiling. Pretty sure I've figured out that I can do the work around the edges and doors first. That way I have a more organised space to be able to get to the ceiling.

Apologies for resurrecting this thread. Keeps related info in the same place and reduces the number of things to look through. I am in the same boat and was planning to put a small amount of insulation between the floorboards and the ceiling skin. The aim is to improve comfort, noise insulation (in and out) and finally to help reduce heat loss from the house due to it being a joined garage. Am I being excessive by wanting insulation or is this a worthy endeavour? I will put effort into the front garage doors, floor and last remaining single skin wall. Will that be enough to help control sound and heat with a basic boarded space above? I guess I could insulate and skin at a later date if needed.

Our gap is extra wide to accommodate the doors thankfully.

Thanks @Kelvin. We don't know which one we are getting yet as the kitchen supplier didn't have many options we liked. It'll be freestanding in the hole so no cabinets to integrate into. Thinking about it now, the height of the hole will be dictated by the existing lintel. As long as the new fridge is enough shorter than that it should be fine. A quick google suggests the difference is enough to create a gap. Must remember not to fill it with stuff!!! Maybe a stylish fill panel with grill would work.

Our design currently has an enclosure for the fridge created by the existing window. As a result it will be in it's own pocket with ~50mm gap all round. Will this cause an issue with the fridge or should we add some sort of vent or even open up the space above? The space is side onto the new WC which will have extraction ducted out. Could we put a small vent from the fridge space into there for the heat to escape or am I over thinking it?

Thanks all. @JohnMo by don't do both I'm assuming you mean don't do PIV and dMEV together. A couple of articles I read suggested doing them together. I guess it's a way of controlling what air is coming in and gives the option for filter and heat? I trust your input though. dMEV units are inexpensive to fit so I think that's the way we'll do rather than MVHR.

I'm coming back round the houses (pun intended) with the whole ventilation thing. BC have commented that we need extract from the ground floor WC (not external walls) and the upstairs wet rooms need new ventilation. My plan all along was to retrofit MVHR. I try to put my money where my mouth is and do things right for all (PV, EV, etc.) and I thought MVHR was the right thing as it would rescue some of the heat lost while still offering some nice fresh air. I'm now considering dMEV as it's dramatically cheaper and easier to install. Then combine it with a positive pressure inlet it basically creates a modular MVHR without the R. Long way of asking: how does a dMEV property cope with heat loss through the ventilation? I don't want to go running the heating only to have it all sucked out by the vents. We also sleep year round with the windows open but was hoping the MVHR would put a stop to that with the fresh supply. Thinking out loud moment: with the relatively low cost of dMEV, could I install that then swap out to MVHR later if it's not enough?

I'm interested in this for a slightly different reason. Planning on capping the chimney to seal it to the elements and maybe even use it as a conduit for ventilation ducting. At what point (vertically) should I add a further barrier? You have chopped yours off. Did you seal the top in any way? I'm thinking of one of those inflatable jobs but nearer the top (accessed via loft space) so the cold region is limited to above the living spaces. I'm probably nuts!!

The extension/build design. Not talking about the MVHR design. Apologies if I'm confusing you.

The design is not based around MVHR and there is currently a plan to have a single extractor fan in the WC that is to handle both WC and utility. I was planning on using that point as the MVHR extract for that area. So you are saying that with MVHR I would need extracts in both WC and and utility. I don't think this would be an issue. Just more expensive in ducting and need to have a think about the site of the utility point. I guess as close to the back door as possible to get the area covered by cross flow.

So the current design has a single extractor in the WC to handle that and utility. Along with an extract hood in the kitchen. Planning on leaving the kitchen hood in place as it'll only ever run for minutes at a time. Just need to make sure it has adequate flappy plate things. The WC extractor I was going to use as the extract from the mvhr. Only thing I hadn't considered was the flow through the wall in the snug. What benefit would that bring over a supply? The airing cupboard straddles that wall below the "U" of utility. That's the route for ducts that side of the house.

For clarification here is a diagram of what I'm intending. The duct would come down from the loft - through bed 3 - out of the ceiling in the living room above the TV.

So I think I've come up with an idea for the living room supply. What are the thoughts on boxing in ducting? The supply could run next to the chimney breast in bed3 and come out of the ceiling in front of the fireplace in the living room. I need to measure the wall placements but it's possible it could drop to the centre of the wall to be symmetrical. That's a detail to figure out later. The duct could then be boxed in as it passes thorough bed3 and it would end up looking like part of the chimney breast. That supply would be above the TV and opposite the sofa (TV over the fireplace). With supplies in the hallway (by the front door) and one in the play room. Then extracts in the kitchen and utility. Would the supply location be acceptable? Would we even need one in the hallway? We are likely to be supply heavy upstairs anyway.

This is something I am struggling to get through to MrsG. I am also generally struggling with design points one being semi-related. Should I have a duct point on the landing? If so should it be in or out? We have 4 beds, a bathroom and an ensuite. Was planning one supply for each bedroom and one extract for each bathroom. Then maybe another extract on the landing as its a tall space that would collect heat. My theory is that it will take that heat and move it to a useable space in the house. Should also reduce the heat upstairs and help with the room comfort at night.

Holy thread resurrection batman! Due to start picking up tools for the extension next month so I am picking this back up. A quick nose on BPC and here suggests the Vent Axia Sentinel as a good option to base the system off. Are there any other brands or models I should be looking at? Requirements are: - summer bypass - boost - reasonable quality - not top end expensive thanks.

Currently looking at what windows etc we want. We have 2 skylights in the plan and my original thought was to not have them as opening models. We are retrofitting MVHR and I didn't want the additional stuff to go wrong. Our builder suggested that they don't go wrong and most have a generous warranty. Thoughts?

I am of the same view as prodave. I'm still designing our system around an extension based renovation. Upstairs only is easy and what a mate has done. Our downstairs is easy to do a basic in and out at opposite ends of the house. The hard bit is getting the supply to the living room. Still working that one out. I believe it will be worth the effort though. Even in a 1970s detached house.

So it seems I did leave some critical info out. The reason for taking the door apart is to convert the single up and over to a pair of side opening doors. Reusing the skin will help maintain the style similar to the other door. I will build a doorframe and a pair of door skeletons on which the skins will be fitted. Then filled with some sort of insulation and a rear skin added. I can design in plenty of seals to help with cold bridging and drafts. Soundproofing will be a happy side effect. Hopefully that gives a better idea of what I'm trying to achieve. Also plan to fit a multipoint lock like in a front door. Should be able to build it for about £300 and be better performing than a door 3x the price. Expanding foam sounds like a good starting point. The main issue I can think of is condensation on the inside of the outer metal skin. The adhesion of the foam might help combat this and also be a bit waterproof at least against major ingress. Thanks for the responses btw.