Ultima357

Just be aware that my original design using the smaller filter did result in the fan working harder to maintain the flow rate, but if that's all the room you have, then it's a worthwhile upgrade. My second much larger design, I mounted the filter vertically so the actual floor space wasn't much different but it was around 1200mm tall. This gives very little back pressure and the fans hardly know it's there. Plus it should have around a 10 year life.

For anyone interested, my post linked above has been running for 3 years now in one form or the other after the upgrade to a much larger filter than the first trial one. My neighbours seem to love bonfires but absolutely zero smell in my house now. Well worth the effort and cost of putting it in. Can't really understand why the MVHR companies don't do it as a standard module.

Well after research, the power module and heater are common across Bosch, Siemens and Neff. As the main oven was sitting on top of it I needed as quick a fix as possible once it was out and eventually found a new slim one that was left over from a job on ebay, so bought it for not much more than the cost of the power module and canabalised it for the faulty part. Which was the power module. Stuck it up in the loft for now but if I can find a new power module for a sensible price I'd repair it and resell. As usual, the price for the official spare is ludicrous at circa £180 for a small board that I reckon has an ex factory cost of less than £20.

Did you ever do it and did it work? Just been researching them but they don't seem to be worth the outlay. Most seem to recommend separate inverter for grid tied systems.

Well we use ours regularly and our previous one was still going strong after 8 years when we sold the house. I'll add that the internals appear to be the same for Neff and Bosch, so any fault will be the same.

Hi. I have a Siemens Warming drawer that has just died despite being only 3 years old. Looking around it seems that there is only 3 key parts, the power module, the heater and the "connector". The first two are quite obvious in the function of things but the so called connector is a bit vague. I'm guessing that this is a simple push to make, push to break switch that switches things on and off as you close/open the drawer and an obvious candidate for a fault. Unit powers on, relay can be heard clicking in and led glows but no heat. In terms of spare parts, the power module is £200, the heater £160 and the connector £38. Big pain is that the oven sits on it so major operation to pull out and test individual components. So wondering if anyone has any insight or practical experience in these? Part number B1630DNS1B, 29cm iQ700 series.

No I've not plotted those but have all the data. I didn't do the full passive certification when we built as didn't think it was worth it. To be honest, the solar gain was expected and probably needs a bit more exterior shading but awnings don't fit easily to a Cedral clad exterior on a timber frame. But there's also not that many days when you can't cool down in the evening simply by opening a window or door, it's just adds to the household dust load though! Solar film is possible but then reduces the advantages in the winter sun when we can get nicely warmed without any other input.

Thanks for that. Your experience indicates my thoughts are along the right lines. Good tip re mvhr too!

Now nearly three years in our new house and very happy with it's performance. However, we get plenty of solar gain and are considering putting in some aircon to three main rooms including the master bedroom. I've had one quote in but not convinced that they appreciate the passive side of things and to cool three rooms are recommending 10kw main unit with three indoor units. Given we heat the entire house with just a 12kw ashp to 22 to 23 deg and in three years have consumed only 7500kwh, a 10kw aircon seems excessive. Only info of passive house cooling I've found to date comes from Perth, Australia where they recommend circa 20w/m2 giving 6kw for a 200m2 property. This compared to 15 to 18kw for a standard build. Anyone had any experience or recommendation on this? NB the three rooms are 35m2, 34m2 and 24m2, the two largest facing south.

Thanks for the replies so far. Today I came across the VSSL A1 which looks pretty interesting but is a tad expensive at circa £560. The chrome cast idea is a great thought although I don't have a spare decent amplifier. But I have a chrome cast dongle somewhere and an old cheapo amp so will experiment once the temperatures return to sane levels.

No unfortunately I built it in a hurry and didn't take photos and it's a bit too warm to go up the attic at the moment. The filter I bought from Future Gardens https://www.futuregarden.co.uk/phresh-premium-filters. It's the 600 x 315 @£188. The cabinet housing I used 15mm mdf and used one and a half sheets. The two sheets cost just under £80 these days with cuts as required so I could get it all in my car. Fortunately I have a CNC router table so able to accurately cut out the required holes and rebates for jointing, so all in around £250. The filter is quite a beast as the 315 refers to the inlet diameter and its around 440mm diameter overall and weighs in at around 18kg if I remember correctly. Basically it's a big box with raised plinth inside across 2/3rds of the depth to hold the filter and provide the appropriate airway flow. Mounted it vertically as that was all I had space for.

Update to this filter. After proof of concept with the low cost and relatively low volume flow filter, I have now rebuilt the whole unit using a much larger filter rated at 2400cu m/hr. The reduced back pressure means the fan works at lower rpm whilst maintaining the throughput and at maximum 330cu m/hr of the MVHR there is very little difference between the in and out fans rpm wise. Given the flow rating of the filter (Phresh 600 x 300), I'm expecting a lot of years service before any need to replace it.

Hi everyone. I'm researching for a WiFi and Bluetooth audio amplifier in order to stream to it from my mobile phone and play my music through a couple of Kef speakers I already have. Be ideal if it supported multiple input devices, had remote on/off via wifi too as I plan to just put it out of the way either in a cupboard or loft space. Speakers will be wall mounted. There are more of these devices than you can shake a stick at so wondering if anyone has good/bad experience or recommendations. I run Poweramp on my mobile with high quality FLAC compressed music. I don't really want to re rip my CD collection into a new device as it's fairly extensive. Happy to switch the amp on/off by smart plug if necessary, preferably without a power on thump through the speakers.

Final comment. Having lived with it for several weeks I can now say it works fantastically well. Yesterday, someone close by was burning rubbish including rubber by the smell of it. Quickly closed doors and windows (it was a nice warm sunny day) and result, absolutely no smell inside. Outside was purgatory! So if you're considering this, based on my experience I'd unreservedly recommend doing it.

Smoke is a very difficult thing to track down sometimes. Tonight we have a countryside scent outside, local pig farm by the smell, thankfully the filter is doing the job!

Sorry for late reply everyone. I set it to flag me on responses but it didn't! Anyway, as for data on how much carbon granules are in it, there is no data on it, but it weighs circa 3 to 4kg and I'd guess the housing being aluminium will be only 500gm of this. There are similar carbon filters such as Carboair which have more data and are probably better. Of course more expensive too and as I am experimenting I choose a low cost item to start with. Typically they filter :- Pesticides/herbicides 0.001nm Paint pigment 1-5nm Odours/Diterpenes 1-10nm Mould spores 10-30nm Plant spores 3-40nm Common dusts 30-600nm Plant pollens 10-1000nm The active carbon bed is 50mm thick. I coated the mdf with two coats of external grade water based clear lacquer to seal it. It's situated on the house supply side so shouldn't get overly moist. As for planning one in at the start, I'd say just give yourself enough room and go my route. The branded mvhr filters are very expensive and I would expect they sting you for replacement filters. As mine is rated for 600m3/h with a life of 12 to 18 months, and I generally run at just 100m3/h, I'm expecting a life of at least 2 years. Time will tell but it's on the prefiltered side so only dealing with the smells, not too much dust, so should be OK. Maybe when it's time to replace I'll use a more expensive version with less back pressure or put a couple of these in parallel in a larger box. I need to make fitting a replacement easier for sure but it's in and working well.

Having lived with MVHR for 9 months I have just completed a DIY active carbon filter as my neighbours just like stinky bonfires too much. Whilst you can easily shut it off when you're at home, it is a horrible surprise to come home to find your home smelling like a bonfire. So I began to research active carbon filters and found those commercially available ones were stupidly expensive and the cost of replacing the filters was also the best part of an arm too. I began therefore at the actual active carbon filter and found that these are many and varied and a huge range of costs. Looking at what I had room to install I decided to get as large a filter as possible and at reasonable cost. I chose one designed for plant nurseries as they are both compact and low cost and got one rated at 600m3/hr with an estimated 3 year life. Again I found a variety of prices but being an experiment, I decided on one costing just over £40 delivered. You can find similar for up to 3 times this. Pictures show the construction of a 450 x 400 x 400mm box in 12mm mdf mainly, just the end out with 18mm to give a greater rigidity for the filter mount/seal. Installed it today and already tested tonight as just had to shut windows due to stinking bonfire again! Running at 220m3/hr currently with no smell whatsoever. Well pleased. Total cost less than £70 for materials. Being retired I don't count my labour. Monitoring the MVHR it has given some additional load/back pressure as expected, increasing the input fan speed by between 50rpm and 500rpm depending on m3/hr selected. The higher rate when running at 330m3/hr. At 100m3/hr its around 150rpm up. MVHR is Brink Flair 400. If this continues to perform, I might go for a higher cost filter with less back pressure when I replace it or see if I could squeeze two of these in parallel into the space I have. Should be possible. Just another 30 quid for more mdf and a few more hours making it. I rebated and glued joints to keep it airtight apart from the lid which is rebated and just screwed down. Hope this might inspire others to give it a go. Filter from Future Gardens, Assasin 600m3/hr. MDF from wherever you can get it. Just two quarter sheets. Plus a few hours design and sawdust making on my cnc router table but could be done using a hand router and table saw if you have a good eye for square and straight edges... ?

Normally there is some mixing of the supply temp to the UFH by buffer tank giving a lower input to the UFH. You can run the UFH at 50 but it uses more energy. With a mix of radiators and UFH and without separate heating control/circuits you are juggling. The system designer should help you out if it's a new system. Basically I'd imagine that your ASHP has a set water out temperature which feeds both rads and UFH so to get the best performance the system should either have oversized rads that can run at a lower temperature or some mixing to lower the UFH feed. UFH is normally set between 35 to 45 deg. If no system designer help is available then try setting the water out temperature back to 45 deg and see how it all performs. If all is well, then try lower still. It is normal for the ASHP to have weather compensation or water law as some call it whereby it increases the water outlet temperature in colder (Eg near freezing) weather.

Those figures are complete nonsense or it indicates something seriously wrong with the unit/installation. Extract air temperature should be roughly the temperature of your wet rooms , say 21 to 22 deg. Exhaust air should be lower, and how low depends on the external incoming air or outdoor reading in your display. Supply temperature should be only a degree or two under your room temperature as the heat exchanger does its business to warm up the outside supplied air temp which in turn cools the exhaust temperature. My Brink at 10 deg outside is currently supplying 21.7 fresh air. House is running at 22 generally but 23 in ensuite and kitchen warm after evening cooking. The Brink gives volume flow rates for both fans so I can see what is happening.

They do, or at least my Samsung one does, BUT, and it's a very big but, the figures it gives are pure fantasy. Actually a work of fiction and completely useless as it claims a COP of 20 at times. ?. I've asked the question to Samsung but still waiting for an answer.

No that's figures over a week or more.

What does passive actually mean? There's a technical standard defined by the Passive haus institute detailed above which you can go for but that's just a vanity £5k spend on a certificate. It basically entails the level of insulation/heat loss and airtightness of the structure. In mine, its 300mm insulation in the walls plus 35mm dead air gap, 400mm in the attic, 300mm XPS under the floor tapered to a minimum 100mm at the dpc edge (so totally enclosed foundations) and triple glazing. All airtight to a measured 0.17ach @50pa. In heat loss terms of U values, walls are 0.1u, roof 0.1u and floor 0.12u. All windows/frames better than 0.8u. A 1930s cavity wall? Well the cavity is likely to be small, so I'd guess the u value would be around 0.5u. My running costs in the past freeze, 15th of Jan to 15th of Feb for heating and hot water around £65. £2 a day. Whole house at 22 to 23 deg plus warm attic circa 85m2 too. 14 zone UFH cast directly into the slab, 155ton heat store. Around 1.5km of pipes! 400l hwt

They do, or at least my Samsung one does, BUT, and it's a very big but, the figures it gives are pure fantasy. Actually a work of fiction and completely useless as it claims a COP of 20 at times. ?. I've asked the question to Samsung but still waiting for an answer.

If you have Heatmiser Neostats, simply set the overnight to 5 deg lower than daytime. Even in a poorly insulated place you'd be unlikely to drop this much. I'm guessing that as you have ASHP then you are decently insulated and draught proof. Not heating some of the house as high as the rest will save some pennies but if your internal walls are not insulated, a cold one could attract moisture if the temperature in these is too low. The cost difference between 10 and 15 deg is not huge and bear in mind that insurance policies usually have a minimum temperature required around the 13 to 15 mark if you're claiming for frozen pipes.

On the PV front, in winter it obviously generates less and as the ASHP will be running, you are unlikely to get much input to the immersion. Summertime yes and plenty of it if you have a decent PV array facing south. You haven't said what your EPC score is and that should come with an estimated heat load if you got a full one. Size of the property is a factor too but I think that ASHP will be an expensive option for heating. I'm running one in a new build passively insulated home (3 to 400mm insulation and triple glazed, mvhr etc), 253m2 and it's rated at 12kw. It copes even in the recent freezing conditions but they all ice up and COP is circa 2 at freezing fog temperatures. My EPC score is A98. Good luck. PS See the Cost of Electricity thread elsewhere on ASHP running costs in a renovated property.