davidc

Thanks folks, it was really the question of how the Fir might perform versus the Larch option (i.e. splitting, bowing, fungal growth etc) in the first place that I'm wondering about most of all.

I have a couple of large Douglas Fir that need clearing from my self-build plot, I am wondering if it maybe worthwhile considering using them for exterior cladding (for main dwelling not outbuildings) if I can get them milled - does anyone have any knowledge regarding that ? I believe Siberian Larch would be better, at least if it was available, but I'm trying to gauge how inferior non-plantation Douglas Fir might be. Does Douglas Fir require pressurised preservative treatment that leaves it with an orange hue ? Thanks

Thanks, @Thedreamer and @Iceverge . I did consider an EAHP but concluded that the air flow rates required (as air has a much lower heat capacity than water) were likely to present some challenges in an air tight home with MVHR. I'm starting to regress back to the mean position of, if a having an WBS, just having it for space heating but the issues surrounding <2kw output, particulate leakage and knowing that the installation and stove itself won't make a sizeable dint in the airtightness remain !

@jamieledI'm starting to think the only way I can do it well with a WBS and TS is the Tonwerk route which put about 1.3 kW to the room and approximately the same to water but at cost of ~£10k for the stove if my currency conversion is right, seems to me, like the tail would be wagging the dog in the sense I'd be spending a fair bit of extra cash just to save some cash. @PeterW that is all new to me, thanks, the house is only 125 sq. m and the budget is fairly modest so perhaps going down that route I'd end up in the same position as above in terms exploiting the free fuel but adding to the build costs a fair bit ? I did think about trying to find out if there was any mileage in getting a pellet maker and seeing if a pellet burning stove would change anything. I may just end up having to have a WBS as secondary heat source - if I can find one with low enough output that is and a better understanding of the supposed problem of indoor particulates and which models mitigate that best.

Several Woodfire models have that split so it may have been one. They aren't DIBt I believe. I'm also trying to accommodate countervailing requirements here as as I'd also like to keep the house as cool as possible over the warmest months - which I think a TS may hamper.

@JohnMo thanks, I didn't have that on my list but it may have a tad greater output that I'd like - hopefully less than 2kW to room The benefit, as I see it, lies in the fact I have unlimited Scots Pine within 200m of the plot and if possible I'd like to use this to provide some of the DHW and heat, the latter (with UFH) in smoothed fashion that also reduces the peak stove output to the room. I don't mind felling, chopping, splitting and storing the lumber. As regards what heats it when a potential stove doesn't, I've oscillated between ASHP and just a simple electric heating element. Thanks, @dpmiller, I was unaware of the FHT stove. Sorry, I'm too daft to know what is meant by direct charge, if asked I'd of said that *was* a coil - but obviously not. Digressing a but, I did look at an Valiant AroTHERM plus .

Can anyone recommend a low room output radiant rather than convective wood burning stove for a low energy airtight build ? Preferably with the capability of heating a thermal store and also DIBt certification ? I've already got some Woodfire models on my list and would also have Tonwerk on it were it not for their astronomical price tag. Thanks.

So have I understood correctly in that an enthalpy exchanger operating at 50% moisture recovery would take out 5gm.m-3 of water from extract air at, say, 10gm.m-3 and put that back into the supply ?

Thanks for measurements, I guess what I don't know is what the RH would be during cold snaps without an enthalpy exchanger. @ProDave my concern was that I'll be reliant on the inside VCL more than if the airtight layer wasn't on the outside which to my mind sounded like a potential cause of increased moisture if the internal AH was higher than it would be for four months of the year than without the exchanger.

I am looking at getting an MVHR system with an enthalpy exchanger as I have chronic (non-allergic) rhinitus that seems to be triggered by central heating drying out cold winter air. The build type is to be timber frame and blown woodfibre with Wraptite on the outside. Regarding the wall type and moisture management within it, should I be concerned that in winter the humidity will be higher than it would otherwise have been without the enthalpy exchanger ?

So does a split unit like the Toshiba Mirai mentioned in this thread need planning permission ?

Well, several months elapsed after the planning work no invoice was forthcoming, I had to ask them to send their bill which I paid the same day as it was received - so I'd hope they wouldn't have be down as a slow payer !

They also drew up and submitted the planning, that time charging in arrears.

Architect has asked for payment in full for work on compilation of Scottish building warrant (equivalent of English building regs) before starting work it. Am I right to consider this dubiously ?

Which, if any, of the Scottish regulations set out what site security measures should be in place for the duration of a build ? I have a pre-existing 1m high perimeter fence and am considering bolstering it to 1.8m but want to check what is actually required for building warrant etc Maybe I'm too impatient with google searches but I could not find anything specific.