Cognis0 Posted November 15, 2021 Share Posted November 15, 2021 Such systems are available from "exotic" European manufacturers coming with galvanized ductwork, to perhaps more basic UK offerings, often with narrow flexible plastic ducting. No doubt there is a significant difference in pricing and, presumably, performance. One area which is very important is noise. My wife is extremely sensitive to electronic and vibration noise and finding something which effectively silent is just about top of the list of requirements. Your comments welcome... Link to comment Share on other sites More sharing options...
JohnMo Posted November 15, 2021 Share Posted November 15, 2021 We have semi flexible 90mm via plenums, and we are the best part silent, that with Scottish building regs requirements of 0.5 ACH, compared to England which I believe is 0.3 ACH. We have two MVHR Units, to enable short runs and low pressure drops, this keeps fan speed down, even on boost we are only at about half max speed. Keeping velocity through ducts low, fan speed low all contribute to low sound levels. Link to comment Share on other sites More sharing options...
Gone West Posted November 15, 2021 Share Posted November 15, 2021 The ducting can be bought separately from the MVHR unit and can be metal, rigid plastic or flexible plastic. The ducting design can also be serial or manifold. I designed my own system which was a serial, rigid plastic ducting design connected to an expensive Danish compact unit. You can choose what you want. 2 Link to comment Share on other sites More sharing options...
Dreadnaught Posted November 16, 2021 Share Posted November 16, 2021 I have just specified and bought my MVHR kit. But I have not installed it yet. I purchased it directly from the manufacturer of the unit I chose. Great service from them, by the way, even including a site visit, when he was in the area visiting someone else (!) Like you I was keen on whisper quiet. First, I chose a PH-certified MVHR unit and bought the ducting from he same manufacturer. Choosing a quite unit I think is key to having a quiet system. And I slightly over-specified the unit too. There was a smaller model available that would have been sufficient but the price difference was small. To tackle the risk of noise, it wasn't required by the MVHR designer who did the calcs for me, but I chose to pay a little extra and double-up almost all the duct runs (other than very very short ones). I also chose to have 1m-flexible-silencers on both the supply and extract from the dwelling. And I have bought a supply manifold which has extra baffling inside too. The ducting is semi-flexible and radial, so no cross talk and I used the wider (90mm external diamater) ducts rather than the smaller ones (75mm external diameter). The expert who sold me the system said that my system should indeed by whisper quiet and the marginal increase in cost will be modest. 3 Link to comment Share on other sites More sharing options...
Marvin Posted November 16, 2021 Share Posted November 16, 2021 Installed my own MVHR with rigid ducting. No machine sounds / wind blowing down a pipe sounds on normal flow. A low amount of air noise at boost level. Noise transfer from room to room will be sorted with baffles . Very happy with system. 100m2 floor. Presently running on a meter test plug at 7.2 Watts/h average over 10 days. MVHR box in loft above main bedroom but you wouldn't know! Purchased a 250m2 unit so running at a low speed... Link to comment Share on other sites More sharing options...
tonyshouse Posted November 16, 2021 Share Posted November 16, 2021 Sound attenuators, ridged metal spiral ducts for me. Oversize and run on low speed Link to comment Share on other sites More sharing options...
Iceverge Posted November 16, 2021 Share Posted November 16, 2021 I built my own silencer. worked very well. Next time i would combine and build my own manifold/silencer like @joe90 did. I would consider building a soundproof cupboard for the MVHR UNIT too. You can hear it when the door to the utility is open. 2 Link to comment Share on other sites More sharing options...
CalvinHobbes Posted November 17, 2021 Share Posted November 17, 2021 We went to the self build show, one of the sales reps said we should pick a system that we can get parts for in years to come - go for a big brand like hitachi, he said. That sounded logical. Link to comment Share on other sites More sharing options...
hendriQ Posted November 17, 2021 Share Posted November 17, 2021 8 hours ago, Dreadnaught said: chose to pay a little extra and double-up almost all the duct runs What’s the benefit of this? Link to comment Share on other sites More sharing options...
Dreadnaught Posted November 17, 2021 Share Posted November 17, 2021 (edited) 6 hours ago, hendriQ said: What’s the benefit of this? The two main sources of noise are (i) the unit itself and (ii) the high speed air in the ducts. And for (ii) especially the turbulence caused when the velocity of that air changes at, for example, the point where a duct joins a larger valve, such as at the point where air is supplied in to a room. (i) is addressed by buying a better quality Passive-House certified unit and fitting silencers. (ii) is addressed by slowing the speed of air flow in the ducts by increasing their cross-sectional area by doubling them up. The rule-of-thumb for noise in ducts is to keep the speed of the air below 2.5 metres per second on boost level. I went even lower. Edited November 17, 2021 by Dreadnaught 2 Link to comment Share on other sites More sharing options...
Dreadnaught Posted November 17, 2021 Share Posted November 17, 2021 Oh, and I positioned the MVHR unit as far away from the bedrooms as I could, even taking the precaution of placing it on the far wall of the plant room. In a well-insulated house, which is airtight and triple-glazed, and which therefore tend to be whisper quiet inside, even small sounds become noticeable, sounds that would normally blend into the background of a normal house. 2 Link to comment Share on other sites More sharing options...
joe90 Posted November 17, 2021 Share Posted November 17, 2021 55 minutes ago, Dreadnaught said: and I positioned the MVHR unit as far away from the bedrooms as I could Mine is in the loft but hung from the roof trusses, on rubber mounts so no noise is transmitted through the bedroom ceilings. Very quiet. 1 Link to comment Share on other sites More sharing options...
Cognis0 Posted November 17, 2021 Author Share Posted November 17, 2021 Thanks for all your comments everyone, which I will be referring back to as I specify/select the system.. Link to comment Share on other sites More sharing options...
Gone West Posted November 17, 2021 Share Posted November 17, 2021 One of the mistakes I made fitting the ducting on my system was to fit an attenuator on the supply circuit and not on the extract circuit. I didn't think it would matter as the extract vents were only in the bathrooms, kitchen and utility. The rooms with supply vents were silent but the bathrooms etc had a slight background hum only audible in the room itself. If I ever design another system for myself I would use two attenuators. https://www.ductstore.co.uk/acatalog/Attenuators.html 2 Link to comment Share on other sites More sharing options...
Cognis0 Posted November 17, 2021 Author Share Posted November 17, 2021 1 hour ago, Dreadnaught said: In a well-insulated house, which is airtight and triple-glazed, and which therefore tend to be whisper quiet inside, even small sounds become noticeable, sounds that would normally blend into the background of a normal house. I could not agree more with this ~ the quieter the house the more accute one's hearing becomes! 3 Link to comment Share on other sites More sharing options...
markocosic Posted November 17, 2021 Share Posted November 17, 2021 14 hours ago, CalvinHobbes said: We went to the self build show, one of the sales reps said we should pick a system that we can get parts for in years to come - go for a big brand like hitachi, he said. That sounded logical. Definitely. So not Brookvent. Those sharks refuse to sell spare parts if, for example, one fan motor dies. (must buy entire MVHR unit) 1 Link to comment Share on other sites More sharing options...
jonc_uk Posted April 14, 2022 Share Posted April 14, 2022 On 17/11/2021 at 15:24, markocosic said: Definitely. So not Brookvent. Those sharks refuse to sell spare parts if, for example, one fan motor dies. (must buy entire MVHR unit) This is not the case. All units from the Aircycle 1.3 onwards are repairable without returning to Brookvent. There is an earlier unit which was sealed and produced for a volume home-builder which has to be returned for repair. After reading this post I phoned Brookvent to confirm they supply spares. I also found out that they would not be able to supply NHBC backed new properties without this. I have the Brookvent Aircycle 3.1 and a replacement fan unit from Brookvent is £294.21 inc VAT. The equivalent part from Domus for the HRX2D is here: http://vent-spares.domusventilation.com/mvhr/spares/hrx2b-hrx2d-motor-2 - for £673! Bear in mind that both fan unit assemblies have a very similar fan and motor costing almost the same from their respective manufacturers. However, the replacement fan is much easier to fit on the Brookvent unit as the side panels come off revealing the fan unit. On the Domus unit, the complete thing has to be stripped down. Brookvent have a 5 year warranty and Domus a 2 year on the HRXE and HRX2D. I know which I would choose. Link to comment Share on other sites More sharing options...
markocosic Posted April 17, 2022 Share Posted April 17, 2022 I stand by my statement that Brookvent are a bunch of grade one c*nts not to be trusted with a 40' bargepole. Why? The earlier unit is very easily repairable - knife the seam, swap the fan, reglue the seam - but the company (a) REFUSE to sell the spare part and (b) prohibit the original equipment manufacturer from selling the spare part to anybody else in order to force you to purchase an entire new MVHR unit. They don't repair them themselves; they supply new assemblies only. From what you're saying evidently the NHBC got fed up with claims (which says something about the failure rate) and forced them to produce a slightly more modular unit. So I'd still eliminate them as a supplier on the basis of their being harks. Dubious commercial operating model / moral integrity. Taking a look at companies house from brookvent is also enlightening. The name might be but the business that sold these units won't be around for future warranty claims. Link to comment Share on other sites More sharing options...
joe90 Posted April 17, 2022 Share Posted April 17, 2022 3 hours ago, markocosic said: REFUSE to sell the spare part a Is,nt there now some legislation that requires manufacturers to make their stuff repairable? 🤔 Link to comment Share on other sites More sharing options...
Marvin Posted April 17, 2022 Share Posted April 17, 2022 On 17/11/2021 at 07:27, Dreadnaught said: Oh, and I positioned the MVHR unit as far away from the bedrooms as I could, So did we. Its above the main bedroom! We have had no noise problem for 4 years so far.... Link to comment Share on other sites More sharing options...
jonc_uk Posted April 24, 2022 Share Posted April 24, 2022 I agree that all MVHR manufacturers should make spares available. In the scheme of things, I would hope / expect that a unit would last an absolute minimum of 10 years. After that point, perhaps it is worth replacing with newer technology which is more efficient. Over the lifetime of the unit, it would be covered by a period of warranty, followed by full spares availability. I would go further and insist that all manufacturers publish the spare parts list with prices. In the case of my Brookvent Aircycle 3.1, the fan replacements are available and a fair price. This isn't published though. With my (now dismantled) Domus HRX2D, the fan unit is available, but an extortionate price, and on top of that it is not simple to replace. It is still early days for MVHR. The general public don't know anything about it and I expect the bulk of demand for units is from volume house builders. There is obviously little demand for spare parts at the moment and there is no secondary / copy replacement parts market. Give it another ten years and things will change as the housing stock with it installed significantly increases. On 17/04/2022 at 08:41, markocosic said: Taking a look at companies house from brookvent is also enlightening. I am not sure what you are getting at here. Brook Vent Holdings Limited (NI057022) owns Brook Design Hardware Limited, Brook Plastics And Engineering Limited and Brook Vent Manufacturing Limited. In terms of ratings, the holding company is most relevant and Brook Vent Holdings Limited has an excellent rating and very low risk according to Experian. If you mean Brook Vent Manufacturing Limited, it has recently been brought out of dormancy. My company would certainly trade with them (on good terms). Link to comment Share on other sites More sharing options...
Cognis0 Posted January 15, 2023 Author Share Posted January 15, 2023 On 16/11/2021 at 16:37, Dreadnaught said: I have just specified and bought my MVHR kit. But I have not installed it yet. I purchased it directly from the manufacturer of the unit I chose. Great service from them, by the way, even including a site visit, when he was in the area visiting someone else (!) Like you I was keen on whisper quiet. First, I chose a PH-certified MVHR unit and bought the ducting from he same manufacturer. Choosing a quite unit I think is key to having a quiet system. And I slightly over-specified the unit too. There was a smaller model available that would have been sufficient but the price difference was small. To tackle the risk of noise, it wasn't required by the MVHR designer who did the calcs for me, but I chose to pay a little extra and double-up almost all the duct runs (other than very very short ones). I also chose to have 1m-flexible-silencers on both the supply and extract from the dwelling. And I have bought a supply manifold which has extra baffling inside too. The ducting is semi-flexible and radial, so no cross talk and I used the wider (90mm external diamater) ducts rather than the smaller ones (75mm external diameter). The expert who sold me the system said that my system should indeed by whisper quiet and the marginal increase in cost will be modest. Would you mind sharing which company designed/supplied your MVHR kit? Many thanks. Link to comment Share on other sites More sharing options...
Dreadnaught Posted January 15, 2023 Share Posted January 15, 2023 21 minutes ago, Cognis0 said: Would you mind sharing which company designed/supplied your MVHR kit? Many thanks. It was the manufacturer Ubbink/Brink. Link to comment Share on other sites More sharing options...
Cognis0 Posted January 15, 2023 Author Share Posted January 15, 2023 👍 5 hours ago, Dreadnaught said: It was the manufacturer Ubbink/Brink. Link to comment Share on other sites More sharing options...
Nickfromwales Posted January 16, 2023 Share Posted January 16, 2023 20 hours ago, Dreadnaught said: It was the manufacturer Ubbink/Brink. What I specify. Very good kit for the money. Link to comment Share on other sites More sharing options...
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