G and J

Am I correct in thinking the pump is running all the time? i.e. the water is constantly flowing round the system thus allowing the ASHP to monitor?

Actually in the ceiling void or hung from the ceiling itself? If the latter I do understand….. except some of the units can be mounted next to a wall into which the drain could pass.

Adding up all the various things said it feels to me like the answer is put in a drain in case but don’t expect it to actually drain much; keep things constant and the house will run well; simple weather compensation will mean the only thing I’ll have to do manually is close the bedroom door on really hot days. Leaving me more time to operate my coffee maker. Spot on!

So, if one has both the slab and fancoils all run together in a single zone, then one cannot run supercool for too long before the floor gets condensy (today's invented word!). But if the fancoil at 12c cools a bedroom v quick is it ok to boost the lot for say 10 to 15 mins without risk of wet floors?

It could drain to any convenient waste pipe using a dry trap methinks, and if a continuous fall is the difficulty then some Fancoil instructions say you can run the pipe to make a deliberate gentle u bend so as long as it has a fall from the unit to start with it’ll work perhaps.

If you have the capability of setting the flow temp automatically just above the dew point then no drain required. Ok, you won’t be able to run super cold so it’ll take longer to cool each room, but it’ll still be better than not having any cooling in each bedroom. If you do go for supercool you’d have to isolate the slab anyway or risk condensation on flooring - not an attractive look - so the above dew point working sounds brill. What kit do you need to implement Rough Lawrence?

So, I’ll assume you are using the fancoils for cooling. Sadly I can’t answer your pipe question, I guess the insulation is only there to stop the pipes dripping condensation if you run your heat pump cold enough to cause condensation. If I’ve understood what’s been said it may be enough to run the pump just above the dew point - but that might mean bigger fancoils as the delta between room ambient and water temp will be lower. But if you do run it above dew point you won’t need insulation on the pipes at all. I'm guessing if you do run it real cold then you’ll need insulated pipes and the drain will become very needed. But hey, sorry if we made you feel left out of the fan(coil) club lol

I want everyone happy, me. Everywhere. All at once. Oh, and I only want it to rain at night.

Oh ok, I’ll install aircon then. My aircon will be a split system with separate heat pump to internal distribution system. AKA ASHP and a fancoil. There, everyone is happy lol

So I need to find one that fits above our bedroom door…

In the 90’s I used travel lodges a fair bit and these ideas have reminded me of them. I can never remember hearing the airflow or being much too hot in summer either. Winter was different, they used have the heating on crazy. So I’ve unconsciously been inspired by a cheap roadside hotel chain. Outstanding! 😕

I did wonder if that would be enough to cool the bedroom sufficiently. I kinda thought well, a drain won’t cost much to allow for condensate if used that way, and allowing for a zone valve to be able to be added later if needed to isolate just the fancoil would be easy too. As for the volumiser, if five days a year for a few hours a day the heat pump ran short cycles would that matter?

Given the recent warm weather it's not terribly surprising that bedroom cooling has been exercising our grey cells. (I wonder if there's a correlation between time of year for design and later overheating issues?) We are committed to ASHP (with some cooling capability) running wet UFH downstairs and electric UFH in all bathrooms, with electric points in case but otherwise no heating provision upstairs. But we also want cooling in the bedroom. The most sensible option for us appears to be a single fancoil unit in our bedroom itself, probably built into the ceiling, but I thought it prudent to ask you guys for a sanity check - not on me, I failed that long ago - but on the plan/placement. The thinking is: The fancoil location is good for pipes inc. the condensate drain, and is away from the bed and behind a wall to help with the noise. Under normal conditions the fancoil will be dormant and not needed for heating though it could of course be turned on to heat. Under mildly warm conditions front and rear windows will be opened to deal with the excess heat. When running the fancoil will push through a lot more air than the MVHR. When in overheat conditions the doors to the bedroom and ensuite will be closed, as will the windows, and the MVHR will keep the air fresh without carrying away all the cool air. So folks, is the above a good plan?

Our first self build went really well, we were incredibly lucky, but it was still enormous stress and we were only in our third decade back then. But, the memory of the stress does quickly recede, but the bloody great big grin inside at the pride of what we have achieved takes an awful lot longer to recede. So when you get to then end it is the most fabulous feeling. In the meantime it might help to contemplate that getting the project started at all is not something the vast majority of people could manage, so you have, it can be argued, already achieved something brilliant. As my wise (but incredibly annoying) Irish neighbour used to say, “don’t look at the pile of wood waiting to be stacked, look at the growing pile you’ve already done.” And smile.

On first investigation it seems that timber frame is fine from all financial companys’ points of view as long as it is sheathed in a brick or block skin. I’m guessing that the British house = bricks & mortar attitude, which in fairness I had a few decades ago, pervades the über conservative underwriting world - remember the three little piggies? It seems that’s not a children’s story but part of building regs from a lenders perspective. They do mention MMC a lot, modern methods of construction, which appears to encompass timber frame without a masonry skin, but we would prefer it more nailed down than us finding a few positive seeming bits of text on lender websites, so that means talking to them. And it may push us harder towards a kit, off-site production is seen as a route to better quality, and as that might speed us up then it might be the answer from all angles.

Introducing Skoobie, a Skoda Fabia and the newest member of the team. Not the first purchase towards the build, we’ve already bought a twin battery Makita chainsaw and Trevor the trailer to help clearing trees, but they were back in January. Skoobie is not in the first flush of youth so fits in well with my (G’s) seventh decade creaking knees, but we are hoping she (yes, this Scooby is female) will do great service in pursuit of our new home. So where is the project now? We have full planning permission but we still don’t actually know how she is going to be built and by whom. It seems such minor details need to be sorted before we can assemble a credible budget. Who knew? Our house is on the market but is garnering little interest, so the upside is we have time to plan everything to death and worry ourselves witless. We’ve done the CIL stuff and they’ve accepted the previous occupancy to reduce the CIL levy should we have to sell in the first three years and they’ve also confirmed our self build exemption. A planning condition prevents starting before September anyway and although we may well start soonish from a CIL point of view with garden clearance and maybe demolish the garage the main action won’t start for a goodly while. There is just so much to think about at once, and it is such a roller coaster of emotions. In the building technology Olympic race we are on the 115th lap (yep, going round and round in circles). Both traditional blockwork and ICF were non starters, kit build companies (SIPs and TF) fell at the high jump as they failed to clear the electric wires on site, so that leaves stick built on site by chippies and a TF kit assembled manually as the front runners, with a SIP kit manually assembled limping in third. On the upside the delayed start has meant I’ve been able to visit two self build sites and learned tons as a result - with me asking more questions than a warranty application form but still being met with such kindness and patience. But time to plan means time to worry too. We thought we were nearing a design which we like which also met all the fire regs imposed by building so close to our boundaries, only to realise that we needed to check that the resulting design would be both mortgageable and lifetime mortgageable - we like to plan ahead and we do want access to funds to grow old disgracefully. We can hope! That’s boiling our brains right now, and getting straight answers from underwriters about a possible future mortgage app is not easy! But we press on regardless…

We’ve had various MVHR and ASHP/UFH quotes from the high power sales outfits and they are educational, though I find their “don’t you worry your little brain, leave the details to us, just agree to pay lots and you’ll be fine” approach just doesn’t sit well. It certainly doesn’t give me the info I need to incorporate the kit into our designs with confidence, especially as these companies typically demand a high percentage of the total cost upfront before doing the design. Perhaps too many self builders have got hold of a free design then ran off and done it themselves thus teaching these companies not to be open. I have found one company that charges a sensible amount for the design stage only, and when I ask them (pre sale) questions about what I need to allow for they are very forthcoming so that stands them in a good light - though no final decisions have yet been made. As for the MCS/grant issue I’m sure I’ve heard of instances where peeps haven’t been ripped off. I suspect there’s an awful lot of ‘oversize to inflate the price and up the labour charge to keep the grant’ type cowboys but there also appear to be good guys who are happy to do a fair job - ok getting in their diary might be tough but ever it is thus in the building trade. The MCS process though also appears to have mild oversizing of ASHP built in presumably partly as a reaction to standard thinking in gas combi boilers and partly to ward off complaints when the heating systems the run aren’t properly designed. For me, boning up and becoming a just about informed enough client is the only viable option. This forum is invaluable for that but it does take a lot of time reading (as J will testify lol).

My multi tool is the only bit of Makita kit I’ve ever worn out, but it has done ridiculously long hours of use, staggeringly helpful bit if kit. Still going but it’s on its last legs. I bought a load of cheap star blades before I discovered quick change blades but a couple of seconds with my angle grinder converts one to ‘tother.

Agreed (but thank you). Back on thread in ‘91 we were building in a row of much older, lower properties, and we wanted to fit in as much as possible. So we set the house as low as possible in the site to reduce our ridge height a few inches. Even so the village nicknamed us Sizewell C. So the rain flows off the road onto our gravel drive rather than the reverse. Which means the drive slowly fills up with soil and the weeds grow very nicely thank you. We needn’t have bothered. Within a decade other houses in the row had been replaced with taller ones than ours. Sigh.

I think a little light bulb just lit in my head…. So when the MVHR is using the heat exchanger there is the possibility of sharing between rooms in the sense that one very hot room causes warmer air through the heat exchanger and thus slightly warmer air supplied to everywhere. But only when the heat exchanger isn’t in use. And whilst this would also work for cooling if not in summer bypass your UFH would have to cool an awful lot to actually beat the benefit of summer bypass…. I think.

I’m sure I’ve read that you’ve got MVHR, so I’m curious, why the wish for the above?

Welcome to this odd world. In the short time I’ve been on here I’ve learned tons of things and perhaps more importantly, I’ve discovered many things I didn’t know I didn’t know. Met some nice peeps too. I'm guessing you won’t be including a well stocked drinks cabinet in your furnishings….. 😉

Have you told them your budget?......when we were first meeting with architects on site to decide who to go with we made our criteria clear......we wanted to be hands on throughout; we wanted them to work from our initial layout; and crucially we wanted to be able to buid in budget.......otherwise there is always the danger of falling for something you really shouldn't be trying to afford.... remember not all archiects " do money" and sometimes they draw stuff that can't sensibly be built

Oh I see. Thank you for that. I assumed (probably because we’ve always done it that way) that the cills were integral to the window. I’m guessing that the cills are sealed to the window in some way to prevent water getting in between the two. Is that correct?

@Conor May I ask what company/product you’ve used? We’ve just started the search for an aluminium windows/doors suppliers and hadn’t thought to check the construction of the cills. We are building timber frame with both vertical wood cladding and render on the outside.