larry Posted March 12, 2022 Share Posted March 12, 2022 Hi, does anybody have any recommendations for a single room heat recovery unit? My mum has a well insulated small house, there is a 125mm hole in the wall already at fairly low level so ideally would need to be reasonably low profile, and reasonably quiet. Link to comment Share on other sites More sharing options...
A_L Posted March 12, 2022 Share Posted March 12, 2022 No recommendations but here are some. https://renergise.ie/shop/energy-saving-products/ventilation/ https://www.partel.co.uk/products/lunos-ventilation-with-heat-recovery https://www.ambientika.eu/en/ambientika-advanced/4893273177373 https://cvcsystems.co.uk/our-products/brink-air-70/ Link to comment Share on other sites More sharing options...
JohnMo Posted March 13, 2022 Share Posted March 13, 2022 https://ecostream.org.uk/d-mvhr/ Not used or seen Link to comment Share on other sites More sharing options...
larry Posted March 18, 2022 Author Share Posted March 18, 2022 Thanks both, very helpful for starters, will let you know where this ends up ! Link to comment Share on other sites More sharing options...
GLPinxit Posted April 23, 2022 Share Posted April 23, 2022 I've thought about this approach as replacements for the bog-standard extractors in the bathrooms in our otherwise fairly efficient 2004 house so I'm watching with interest. I'm currently deterred by the limited choice to fit the existing holes in the walls and their high unit cost (we would need four). My contribution https://www.vent-axia.com/range/lo-carbon-tempraselv (not seen or tried). Link to comment Share on other sites More sharing options...
JohnMo Posted April 23, 2022 Share Posted April 23, 2022 I would really look at the cost benifit v cost. dMEV fans may be a much better option, worth looking at. Link to comment Share on other sites More sharing options...
George Posted May 3, 2022 Share Posted May 3, 2022 Isn't that the same thing? Link to comment Share on other sites More sharing options...
JohnMo Posted May 3, 2022 Share Posted May 3, 2022 No Cost is simply how much something costs. The cost benefit, is what it save you by installing product A compared to B. A normal fan, on demand high flow rate when it's on, no flow when off. dMEV more expensive than a normal fan, but can lead to better air quality as its on all the time, uses low energy motors low flow rate all the time. Single room, MVHR, same flow rates as dMEV, but two fans to drive. The saving come from heat recovery. So if comparing dMEV with MVHR, the cost to install each will be £xxx or £xxxx, then you need to calculate the ventilation heat loss for the room and see if the payback time is worth the expense taking into account the heat recovery efficiency. Link to comment Share on other sites More sharing options...
larry Posted September 3, 2022 Author Share Posted September 3, 2022 Updating on outcome here. I ended up using an Europlast EER125 single room heat recovery which I got on eBay for £110. Fitted today. Easy fit, like an extractor fan. Works by reversing directions of air flow every 70 seconds. There's a ceramic heat exchanger inside which presumably collects the heat on the exhaust cycle and reuses it when it pulls the air back in. Two modes of operation fast and slow. Slow is not too noisy at all. You wouldn't want fast in a bedroom but fine in a bathroom/kitchen. Only issues I can see. You have to in theory wash the filters every three months so that means unclipping the grille and pulling out the heat exchanger. How many people will be bothered to do that in reality I don't know. Second issue, you definitely need a 127mm hole not a 125mm one, and you need the hole to be dead straight. I had a bit of a small bend on the hole when it crossed the cavity (was reusing an existing hole) and it caused the plastic tube to bend slightly which meant that the fan caught on the edge and made a noise. Needed to remove and expand the hole slightly. Will wait for real world performance in the winter but so far so good and certainly a step up from putting in an extractor fan. Hope this helps somebody considering a similar option. 1 1 Link to comment Share on other sites More sharing options...
larry Posted September 3, 2022 Author Share Posted September 3, 2022 Oh, one more thing to add. The noise is not entirely constant. When the fan changes direction, you hear it quieten and then speed up again. Link to comment Share on other sites More sharing options...
Ferdinand Posted September 3, 2022 Share Posted September 3, 2022 I've only just seen this. I'll add that I have been fitting the Lo Carbon Tempra P version (not the SELV one) for years in rentals (first in about 2013), paired with a PIV Loft Unit to give a throughput, and I have never had any complaints - except fitting a HRV in a bathroom. Because the air incoming is inevitably slightly cooler than the outgoing as efficiency is never 100% - so it is perceived as a cold draft by people just out of the shower. So a PIV might be next step if you need a gentle throughput for the whole house. Interestingly had a comment from a T today who pointed out that her unit has a Hi/Lo/Boost switch on the outside, which the early ones don't - and that her kids put it on boost, and that she notices the lower power used on her Smartmeter by turning it down. F Link to comment Share on other sites More sharing options...
larry Posted September 4, 2022 Author Share Posted September 4, 2022 V helpful 13 hours ago, Ferdinand said: I've only just seen this. I'll add that I have been fitting the Lo Carbon Tempra P version (not the SELV one) for years in rentals (first in about 2013), paired with a PIV Loft Unit to give a throughput, and I have never had any complaints - except fitting a HRV in a bathroom. Because the air incoming is inevitably slightly cooler than the outgoing as efficiency is never 100% - so it is perceived as a cold draft by people just out of the shower. So a PIV might be next step if you need a gentle throughput for the whole house. Interestingly had a comment from a T today who pointed out that her unit has a Hi/Lo/Boost switch on the outside, which the early ones don't - and that her kids put it on boost, and that she notices the lower power used on her Smartmeter by turning it down. F V helpful. Does that model work the same way? I e. Alternate extract/supply cycles over a heat exchanger? Looks like there might be more gubbins in the wall unit on that one. Link to comment Share on other sites More sharing options...
Ferdinand Posted September 4, 2022 Share Posted September 4, 2022 1 hour ago, larry said: V helpful V helpful. Does that model work the same way? I e. Alternate extract/supply cycles over a heat exchanger? Looks like there might be more gubbins in the wall unit on that one. It now has what it calls an intermittent mode (which is new to me), which sounds like that. I bought them initially for the trickle mode, which only uses 3W on low trickle vs 15W on boost and 20W on 'intermittent', and their third-off the price "carbon reduction week" where there is an 80% efficiency heat exchanger and separated as far as possible inlets and outlets. There's also some burble about maintaining a slightly reduced air pressure relative to the rest of house for something something something reasons, which I think is probably half burble but also a minor effect. https://www.vent-axia.com/range/lo-carbon-tempraselv And having a PIV at the other end of the house helps resist eg towels on radiators or the "what? windows open?" tendency. F 1 Link to comment Share on other sites More sharing options...
Miek Posted September 4, 2022 Share Posted September 4, 2022 The Lo Carbon Ventaxia ( which I have one of) has a counterflow heat exchanger ( straws in a pipe type) and two fans for balanced air flows. So not the same as the flow reversal type. IMO the flow reversal types have very inefficient heat exchangers despite their claims due to the way they work. They simply cannot recover much heat since they don't have a counterflow heat exchanger. 1 Link to comment Share on other sites More sharing options...
Ferdinand Posted September 4, 2022 Share Posted September 4, 2022 FWIW I have usually bought my units on price, and the best value has been somewhere like FastLEC. They are a very generic boxed product so I would just buy on price subject to a reasonable expectation on reliability of supplier. 1 Link to comment Share on other sites More sharing options...
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