MikeSharp01

With us there is no room for them before the distribution plenums so they will need to go on the other side between the titon and the outside air but I do have room inside the DIY plenums for some foam etc. Not sure what the effect of having the attenuator on the external connections is though.

We are just about to put the MVHR unit in and hook it up to all the ductwork and the outside world. We have a Titon HRV4.25 Q Plus B2 (with the aura controller) and I am not sure what attenuation strategy I should use. I have read loads of stuff on here and elsewhere and also spoke to the technical team at Titon (can't praise them (him) enough) and he suggested using two of their 1m semi flexible attenuators although I know some on here advise against these devices. I had intended to put the attenuation into the distribution boxes, so after the unit in supply and before it on extract, which I will custom make, based on ideas shown elsewhere here, to fit the space and allow maintenance but his suggestion - which will be the other side of the unit on the connections to the outside, has some advantages eg getting fitted in the space /lined up. I do want to to be as quiet as I can get away with. Any thoughts.

We still have our problem in that I cannot actually do a DIY job for the difference I would need to pay a over the grant amount 4K ish based on all the quotrs we have had. I am now looking at the Umbrella schemes to see if I can use that route. It is an official MCS thing but finding a partner local enough to do their bit is proving 'interesting'.

The coffee machine!

Thanks all - I will get back to it at the weekend, draining it down and fitting a new 3 way valve as the current one seems to be letting by, which may explain where the flow is going when it should be going to the furthest rads, the TRV is the right way round its not stuck as I can push it down no problem so it must be an imbalance - has been working fine up until now - still best get it sorted before the winter comes.

At the bottom - they are tall wall rads 1.8m high.

Just doing a check through our heating system at millstone manor, ready for winter, and have come across an odd problem. We have a radiator where the feed pipe is getting hot, there is no bypass pipe, but the radiator is not. I have had the rad off, checked it is not blocked and both valves are open, same problem. Feels like an air lock but the radiator bleeds fine. Any thoughts?

Not sure where they get, probably missed something I have, the SCOP of 1.75 in HW mode from even the highest temperature output in the heatpump specification is 3.47 @ 55 Deg C after which it drops to 0 which implies it won't go there!

No piling, just three cores to check the state of the clay below the slab. We scraped off the surface buried the soil pipes, put in the peripheral drain and then back filled with type 1 - rolling and levelling in layers, then covered in pea shingle before putting down the insulation modules, put in the dpm, made and installed the reinforcing , attached the UFH, poured the concrete.

Passive slabs are more expensive than strip foundations but your soil conditions are the same as ours, although we have no large trees close, so no reason not to. You need to get a proper structural design based around a few cores taken by a soil mechanic as we did. The rest was just hard work - but worth it.

But the PHPP has a cooling via MVHR option that cannot be done feasibly with direct electric - unless you can afford a big enough thermoelectric cooling plant, so ASHP will be a good option for that.

Then it should be OK but check the technical guff on the unit to ensure it can deliver under your circumstances - I dimly recall you need to have a given output temperature for the unit to get the tick in the box and that's a variable.

We have thought about this one a lot - as we approach more advanced years, not so much for the ovens but for the fridge, we have no high units, other than one place in a wall for the ovens - maybe you could do that, in the kitchen only the utility. We have looked at the under counter pull out fridges - EG the Liebherr UIKO1560 which should make access easier and then have a fridge freezer in the utility room for deeper stock! PS - BUT before you take aboard your sons advice ask yourself how often they took aboard any of yours.

Sounds like a plan the PHPP software will tell you if it's a goer!

The heat load is based on the worst day of the average year not the worst monthly average. So bunging the average in won't get you the passive house outcome - you need the worst day, the maximum energy needed to maintain the temperature difference. See here: https://passipedia.org/basics/the_passive_house_-_definition

1 mile is beyond range of 5G mm wave, very high speed, which has a max of 600m range, low band 5G would get there but is much slower maxing out at 50Mbs top end of 4G is in theory better but your speed will be all about how busy the cell is.

Just ran the free version and it gets close to the PHPP outcome.

Can't tell you what that is because the sheet is locked and its on a hidden row, however by unpacking it (pasting the formulas from the hidden rows into another sheet) I can see it takes more factors into account, there are intermediate rows, than are in the table shown above - so I guess its complicated but it must just, in the end, be some function of the values shown.

I found this relatively straightforward guide to the difference between heating demand and heating load. https://sustainableengineering.co.nz/qa-with-jason-explain-heating-load-vs-demand/ there is also a discussion here http://public.wookware.org/gbf/newforum/commentsbb9a.html?DiscussionID=13647 on GBF looking at the same issue. Essentially the two values don't have a direct relationship, and you need to know that the Passive House Planning Package (PHPP) & passive house concept generally, has this concept of treated floor area (TFA) which differs from the more traditional floor area - but not significantly for most designs, in ours TFA is 139, and actual is around 150, this is used in PHPP for calculating both Heat Load and Heat Demand but that is where the similarity between the two ends. Heating load is: the number of Watts you need to pour into the house across each square meter of the building's TFA to keep it at set point temperature at the coldest point of the year (it has no time dimension so its an instantaneous thing). In our case this is 8.268W/m2 according the our version of PHPP. Given we have 139m2 of TFA we have therefore need a heating plant capable of delivering: 139 x 8.268 = 1149W or 1.149kW (Which on reflection is bonkers small but that is what PHPP says it is) and as you cannot get a ASHP below 4kW that is the size we we will need. Actuallly in our case, assuming we could get the flow temperature above 42oC space heating via a heat battery in the MVHR would be enough in our case but we have UFH in the slab anyway and will use that. Heating demand is: the total amount of energy required to keep the house at the set point temperature across the whole year, based upon: the average outside air temperature (OAT) each day / week / month (monthly and annual for PHPP) the amount of gains & losses from things like Solar gains (N/S/E/W + Horizontal / Ground) and internal heat gains (people / things / operations - EG Washing up & running the fridge and your mega sound system!) Here is what that looks like for our build in our version of PHPP : So we have will use 1465 kWh/a which comes out at 10.512 kWh(m2a) using the monthly method on our 139m2 TFA given a coefficient of performance (COP) of 3 we will need to pour 488kWh of electricity into our ASHP to keep the house at set point (without cooling - cos PHPP says it won't be a problem, even if I think it will) at 30p a kWh that comes out at £146 pa. Does that clear up the differences for you?

Hi and welcome to THE forum for people like us - looking forward to hearing more about the project and getting your input on heating, which is a widely discussed topic on here.

Interesting. I have one 'radiator' unit I brought to put in the MVHR supply line to allow heating / cooling but I could get another and make two of these, one for each bedroom!

Is this not the very definition of short cycling? Would it be better to run the cooling longer at a higher temperature?

So I clearly need to think this through. I cannot run drains as all the pipe runs are in the ceilings so above and supposed unit. Insulated pipe runs not difficult in the ceilings Electricity is no problem - what controls do these things have?

Just a temperature & relative humidty (RH) sensor, such as the DHT22.

Are you insulating them? What water temperature are you running the FCUs at?