WisteriaMews

@TerryE thank you for the detailed reply. I'm not as IT savvy so the above is probably a bit advanced for me! 🙂 Might be a silly question, but how.did you install the top and bottom thermometers? I'm assuming they are on the outside of the tank? Did you try to get round the insulation to install them on the metal skin of the tank? It sounds like you only use a top temperature sensor to drive the boost if needed? Being able to have a boost is my main concern, so I might be able to do something simpler than your setup. (I'm planning to be on Go / Flux rather than Agile so will have a set block of off peak that I can just use a timer for.)

@TerryE @JanetE I'm looking to specify the same tank in my new passive self build, but have been struggling to find out many specifics about the controls. Ideally I think I'd like to: 1. Heat to full overnight on off peak electricity - it sounds like it has timers so this should be possible. 2. If the tank falls below a certain level boost it so there is enough hot water for evening showers / so we don't run out etc... - I haven't been able to find anything on a 'smart' feature like this being possible. Are you able to share your experience with the tank controls. Thanks.

PHPP tells us it's sufficient. Still feels like a bit of a leap of faith installing such a low power system.

Yes, our architects are Passive House qualified.

We're planning a certified passive house and are looking to install a Zhender ComfoAir Q450 with the Zhender Comfoclime bolt on that does heating and cooling. Assuming we hit the passive house standard, that should be sufficient for us. I see you mention above UFH (and also have seen your other post about ASHP), if you get a heat pump that can reverse you could do both via the UFH; heat the slab in winter and cool it in summer.

Not much further forward, currently waiting for the structural engineer to finish a few pieces before we can fully engage a timber frame suppliers. We're in London.

If you are happy with them, could you share who supplied your external blinds? I think we'll be installing some as well.

Thanks for all the info. We are looking at an Oso cylinder having seen it mentioned on the forum.

Our architects are doing the PHPP modelling so I'll ask them for the cooling load. We are currently aiming to be certified.

The MVHR design / modelling we've had done shows 229 m3/h or 286 m3/h on boost. The Zhender data sheet (thanks for the suggestion to double check all this) shows 1.1 kW of cooling at 315 m3/h, so we'd probably get ~1kW on boost. Possibly not enough..... What types of intervention do you use on hot days?

I'm pretty committed to getting a panelised system from an experienced passive house supplier. There are no experienced passive house builders near me, and I don't have a relationship with a building company who are committed to getting into passive houses / getting it right, so I see a panelised system as a lower risk option. We self built our current house and despite using a 'good' local builder, I've been disappointed with the thermal result (air tightness / thermal bridges). This has definitely influenced my decision for our next project.

Not ideal! Our architects emailed them around the time we got planning and they gave us an estimate and seemed reasonably responsive then. We're now at the stage of getting more serious and working out the finer details with the front runners.

I realise this is a slightly "how long is a piece of string" question.... We are finalising the technical design / specification for our passive house and are keen to install some cooling, to counter the over heating days and effects of global warming (as best we can). PHPP will tell us our heating demand (e.g. 10W/m² heating load), but I'm not aware of it giving a cooling load. We are considering a Zhender MVHR with Comfoclime 36 add-on that can provide 1.7 kW cooling capacity and 2.2 kW heating capacity. Has anyone got any advice on whether that cooling capacity will be enough? We're currently also finalising the external shading, but intend to have shading to stop the house getting too hot in the first place.

Has anyone used White Haus (https://white-haus.com/) for their timber frame? They are one of the front runners for our passive house project and we were looking for feedback from anyone that might have used them / considered them. They seem to be one of the lesser known timber frame suppliers and are part of the Intelligent Membrane / Passive Purple group of companies.

I've spoke to a couple of warranty companies and they told me there were no special requirements for covering a basement. However, it seems to be standard that they don't cover water ingress (which is why they don't insist on an insurance backed guarantee). We're looking at Type B & C waterproofing on our basement. If anyone has any recommendations of companies they've used please let me know!