Leaderboard

Well time (quickly) and build (slowly) have moved on. So an update is in order. MVHR is to be a Zhender Q600 comfoair system with the Q600 comfocool attachment. Ductwork is rigid Lindab and currently installed in Tom's, our next door neighbours. We are both pretty much water tight although 5.8M Internorm doors are yet to be installed along with some other Internorm windows and doors. Second week in November for the remaining doors and windows. I decided to go with SunAmp 5kW PV with 5kW expansion. That is until I got the schematics and found that they (SunAmp) supplied the two units in a series configuration. So flow seriously compromised by 15mm pipework throughout. I was expecting them to be connected in parallel! So I went back to SunAmp to cancel the order and revert to thermal store. However, I am now awaiting confirmation or otherwise from SunAmp on early deployment of 10kW mini stacks which feature 22mm pipework throughout. I will get to know this week so decision in the balance. If we get offered a ministack solution then Electric based Duct heaters, rather than hydronic Veab Duct heaters will be required. We already have the VEAB units albeit the wrong diameter (too small) ..... another story! In answer to the question by PeterStarck, yes the outer EPS of the Isoquick lines up with the outer EPS of the Beco walls. The wall to truss joint was always going to be a thermal bridging challenge though not a huge issue. The warm roof comprises of 2 x staggered layers of 100mm thick PIR fastened to 11mm OSB deck (Sarking) across the external edge of the roof trusses then membraned battened and tiled. Between the trusses is an additional 100mm of acoustic/thermal insulation followed by the airtight membrane (Pro Clima Intello Plus). The roof insulation continues under the exposed ends of the trusses ( between truss and Soffit) to meet up with the wall EPS. Internally the truss to wall plate joint is filled with Thermal/acoustic insulation to minimise thermal bridging. 6kW of Solar PV is to be installed; 3kW on each of the East and West facing roofs. If looks like we will use electrically heated towel rails and an electric duct heater in the groundfloor MVHR supply loop only IF we go with SunAmp. This is because there is no stored hot water in the SunAmp based system. I have attached the space and DHW system as employed in our other Passivhaus. Clearly, this will be different for the current houses but with same functionality. Depends on whether we revert to thermal stores. roof wall junction detail v2.pdf Saddleback Heating and DHW.pdf

Oh, and if you find a good plumber I'm happy to speak with them if there are any aspects of the remit they're unsure about.

An excerpt from the ERP guidelines update. Quote .... " The modulation of oil-fired boilers The major stumbling block is on the modulation of an oil-fired boiler. Generally speaking, certainly in the UK, a domestic oil-fired boiler typically has a fixed burner, a non-modulated burner. It simply cycles on and off when it reaches its required temperature. However in the current proposals, manufacturers would incur a penalty of 7% on the overall efficiency of the boiler. We consider this notion to be very unfair as we don't see any great difference in efficiency between an on/ off burner and a modulating burner. As a result we believe, a penalty which takes 7% off the efficiency of, for example, one of our oil-fired boiler will make it difficult, if not impossible, for oil-fired boiler to continue in the UK without changing to a modulating burner. A modulating burner would cost almost double the price of the present burner used in oil burners and also require an increase in controls complexity. All of which are relatively untried and tested so as a result we think it could signal the end of oil-fired boiler. In what is generally a price-sensitive market, the price of an oil-fired boiler would increase significantly, thereby reducing accessibility and meaning homeowners would probably be forced to look for other means of heating their homes." Delete his phone number. He clearly doesn't understand the problem. ( * ) There's no way you'll be able to run the Ufh direct via motorised valves and an UVC unless he proposed fitting a large, as in 300ltr, buffer tank. It's not about efficiency, it's about being matched to the heat load properly. Condensing is nothing to do with modulation, and it's modulation you'd need to lower the heat output to run the Ufh efficiently. As the boiler is basically on or off ( 100% of the heat capability or 0% of it ) then you need to use a TS or buffer to capture and hold the pulsed-in high grade heat so the Ufh can just gently draw what it needs and in the quantity it's needed. The use of a TS also means you can set the boiler flow temp and the TS stat accordingly to dictate ( near as damnit ) the return temp. That means you can optimise the efficiency of the boiler by staying in the ideal flow - return temp range to promote full condensing operation. ( * ) In the boiler manufacturers installation instructions ( MI's ) it'll actually say that you need to 'design out' any scenario which would result in the boiler 'short-cycling', one which the UVC and direct fed Ufh would instantly create . A poorly designed system could see you with no warranty as short cycling an oil boiler will seriously affect it's longevity, plus it'll be using a lot more oil.

I don't have a problem with claims that it can help reduce dissolved oxygen, as can lots of other separators, but what has that to do with the price of sliced bread or claims of improving boiler efficiency and heating bills by tens of percent?