Iceverge

https://www.aivc.org/sites/default/files/14_2.pdf Pretty good.

Ok lets play the game with out own situation. Lets DIY/ Electician install some PV. The bits for a 5.8kWp system would come to about €3800. Lets say the install costs €6800 assuming I did the climbing myself and got someone else to do the wiring. PVGIS predicts 5.3MWh of production. Lets say 4.8MWh to be conservative. At a feed in rate of 24c/kWh it's never worth using it to heat water and almost matches the equivilant day tariff. Export would be about €1200 per year. A payback of about 5.5 years. Relatively convincing. Now assume the feed in tarriff doesn't exist. We self consume 4000kWh per year which would otherwise be bought in at a rate of 19c. I reckon payback slips to 9 years. Less convincing but OK. The bottom line is that unless you can't avail of cheap overnight tarriffs or have very very hight water usage I wouldn't get too worried about using a TOU immerson for DHW.

As far as i know this might be one of the few remaining justifable use cases for solar thermal. You can get a stand alone heat pump just for DHW too. I've been pondering this. to see if it will reduce our €400/year DHW bill for about 3500kWh at a TOU tariff of 12c. For a capital cost of €1,230 plus bits and pieces and fittings, say €1500 DIY cost. At a COP of 2.5 it would reduce the kWh usage to 1400kWh. However due to the lower storage temperatues I reckon half the heat imput would need to be done at the more expensive daytime rate of 26c/kWh. So 700kWh@12c + 700 kWh@26c = €266 per year. A saving of €134 per year. A payback of about 11 years assuming it doesn't break. I think I'll keep my money in my pocket.

It's a great technology. Keep us posted on how it looks. I wouldn't rule it out doing it to our house in 20 years time if I think we've lost some airtightness.

I really don't think extra ventilation is needed for a stove beyond house leakage. The primary cause of carbon monoxide poisoning is from a blocked flue. Does anyone have any documented case of solid fuel fire carbon monoxide poisoning, that was caused by inadequate air supply to the stove, rather than just arguing "it's what the rule and regs say mate."

On the subject of external air sources I'm not convinced. I don't think the physics check out. The fire will expend the same extra energy either heating the cold external air up to combustion temperature or else heating the room air in compensation for the increased drafts. My inner scientist says it's ultimately the same thing but with the external air you've made an great convective cooling device for the days it's not lit. Our house air tested at an equivalent leakage area of 49cm². Orders of magnitude tighter than any old house but still more than enough area required for a stove on half damper. Even for a passivhaus I don't think all this extra ventilation is required. Just open a window while you light the stove, then when up to speed the 5kW stove will find it's air from somewhere.

Ah I've actually taken the time to read properly now. Ensure that the chimney is free from any built in timbers and is sound before the liner is inserted. A house near me burnt down when a stove liner ignited an old timber built through the chimney. It was never an issue with an open fire for centuries but the very high temperatures of the stove exhaust via the liner caused it to ignite.

Still Neither! Any of these will be better. Remember that your chimney is equally important to the performance as the stove itself. What's the plan there?

I'm going to take a dive here and say neither. They're both too cheap and "makey uppy" brands. You need to think about long term servicability/parts as well about quality. Small quality stoves typically run about twice the price. You'll have to go play with a stove to see what it's like. Check how tightly the door seals, if it's got a cool touch handle that you can open the door without leaving your skin stuck to it. If it's got an ash pan that can be removed without filling the room with dust. How easy it is to clean. I would always prefer a tall fire box over a wide one as the fire will self feed then to some extent. Make sure the firebox is big enough for your chosen fuel too. My preference is for an enamelled surface as it's easier to keep looking smart. Running a smaller kW stove is always better than sooting up a large one. I wouldn't worry about this. Charnwood make good stoves. This is lightly to turn into another annoying thread about the virtures of woodburning. Can we all pleasea void this for the 900th time by taking it @Sam odell understand and accepts that stoves: Elevate the risk of all the occupants of the house developing heart, lung diseases and cancer Contribute to localised airpollution on a scale that would make a diesel lorry look like a daisy Is a very expensive way of buying kWh of energy into your house. Makes the living room very dusty.

It really isn't the end of the world that price. I assume it'd cover your blowerdoor test too. Beware that it might still not function if you don't do a reasonably good job with airtightness in the first place. It's designed only for blocking small holes. It isn't magic. I doubt you'd get a satisfactory result for example with your architect's roof details. There'd be far too many gaps the size of a 50p left to ever expect a method like that to work. Whatever you do if you want a house thats not leaky as a sieve you need to have a good design from the outset.

I think it was @SteamyTea who was of the view that keeping heating and DHW separate was a good idea. We just use an immersion on a TOU tariff of 12c/kWh and a 300l dumb UVC. It's controlled by one of these. A 4kWp PV setup would cost about €7.5k at the moment to pay for it to be installed. Over 25 years that's about 10c/kWh so the case for complicating the system further is very slim. If I DIY install the PV it might be different.

I'd much prefer to substitute the PIR for mineral wool in the roof above scenarios for @Indy but I think given the cost differential and the on paper reduction of U value I think I'd be shouting into the wind. This would be better is almost every way. Espically long term performance and fire prevention.

Gas migration, shrinkage, cost, off gassing,thermal bridging through the foil, recyclability, durability, permeability, hydrogen Cyanide gas when burnt. Grenfell.

Personally I think lots of these things are a legacy of not having modern machinery. Strip foundations require minimal concrete which used to be mixed by hand or in a small drum mixer. Like wise block and beam or a timber suspended floor can be handballed into place off the back of a builders trailer with no machines needed.

Flat roof is much the same as the pitched roof so I haven´t labled it. You could use 22mm OSB instead of the plywood in 2400x600 sheets. It would be easier to manhandle onto the roof and offer much the same pullout resistance as the ply if you missed the rafters with the screw.

I've never seen block and beam close up. It's ground bearing slabs all the way near where I'm from. Our first floors are precast hollow core planks. An elephant wouldn't disturb them but I think it's an overkill for a house. I understood that on some clay soils b&b was required due to ground heave etc.

No for heating. We were tipping along only with a plug in radiator but at 3.2MWh annual heat demand and €0.25 average electricity price the heating bill has risen to €800. Hopefully the A2A will reduce the bill to about €200. 2-3 year payback.

Thats a start! Notes: The seperate DPC works fine for both cavities, its what we did. THe DPM is between 2 layers of EPS, protecting it. EPS 100 will take UFH staples better than EPS 70. The cavity extending well below the floor insulation is required to prevent mortar dropping making a thermal bridge here. I haven't included any periscope vents for the void in the drawings. The French drain will really protect the floor from dampness and allow everything to stay dry and perform much better. U value is about 0.14 worst case.

We have a single Daikin FTXM25R in the hallway a couple of these in the bathrooms for showers. Heat demand of the house is low though.

Correct me if I'm wrong here. You have a vaulted living space that will be 6.7m wide so each rafter will span 3.35m and will be supported at the top by a ridge beam and 2.9m walls at the end. The ridge beam could be Gluelam, it depends how long it will be. The gable end wall will need to be strong Probably requiring a post to take the load to the foundation. I can't see why this couldn't be timber too. Depending on the amount of glass you plan to have.

Flow screed isn't a bad idea actually. I forgot that it was above block and beam so 100mm of concrete wouldn't be really required. I can't see how the Architect could possibly get to a U value of 0.15 from 100mm PIR. Closer to 0.22.

Don't do this. Use EPS beads or mineral wool instead.. Our a2a is in and working well with 3 weeks. COP of about 3-4 at a guess.

Exactly the same logic I reckoned with. Did a masonry build but it's not an enjoyable experience to do it properly. The dense pack cellulose really helps with MBC and other TF builds. I would probably stick build and use cellulose next time.

@Indy I've put a good bit of consideration into the above. Materials etc weren´t selected at random so if you have any specific questions fire away. I think it'd actually be much cheaper than what your architect proposed too by the way.