MirandaPoth

The HW loop is on while we’re awake, typically 6am til 10pm. It’s off while we’re out (shopping, holidays, trips out - it turns off when our alarm is on). It’s a 250 litre tank and typically I guess we’re not using it all in a day (shower on for say 20 mins a day, a little washing up only as most goes in the dishwasher). (It’s a big tank because it’s a big house with a big bath and we didn’t want to run out when we have visitors!) We’re going to fit an electronic temperature sensor on the tank to see what it actually is - currently it has only the bimetallic strip one that links to the boiler. I guess we could replace it with one that could be controlled programmatically from our Home Assistant server, so that it could periodically heat it to the higher temperature.

VERY interesting. Thank very much @JohnMo. We actually have a hot water loop in our setup, I wonder if that is enough to ensure a full change of water every 24 hours thus avoiding stagnation?

Interesting! I will look that up. Thank you!

Thanks everyone for your input. The hot water tank is well insulated and to avoid legionnaires it's at 65-ish deg C. There isn't really space to partition the room unfortunately, we thought about that. Our 'several servers' are part of our smart home & audiovisual systems. The whole point for security, speed, cost etc etc is that they are on site so that as little as possible is reliant on cloud services. We are getting quotes for a small split AC system; as @Nickfromwales said, this is probably the best solution. Thanks Nick 🙂

Boiler, hot water storage tank, selection of HP switches, CCTV system, several servers, many small hubs for the smart home stuff, and the MVHR units itself. Hot water pipes are all lagged already, although there might be a few bits that aren't (valves, joints)

I've just checked the running temperature of the UDMPRO. It's running at 46 deg C, which is about 6 above spec

Hmm I see what you mean. However hubbie is an electronics engineer and is unhappy about it running that hot all the time. Plus we have to leave the plant room door ajar all the time otherwise it gets much hotter, which isn't ideal ...

Thanks very much for your reply. Yes we do have an MVHR extract in the room, but it doesn't help with the heat buildup in summer. We're hoping it won't pull too much air from the room but I take your point about knocking off the MVHR airflow balance. Yes it does seem like overkill, especially as the smallest split units I've found so far are about twice the size we need. Although it would be nice to have a cool room in the house, as we are lacking one at the moment! Not sure what other solutions to look at. Any ideas?

The 12.5m3 plant room containing our servers, switches, hubs etc in our passivhaus-standard home gets too hot (28-30 deg C). We want to install a small, efficient, ducted aircon unit to cool it down to around 20 deg C. Heating, air purification, dehumidification are not required as the MVHR takes care of those. Our water storage tank, boiler and MVHR unit are all in the same room (which probably accounts for the temperature lol). We built the house ourselves 5 years ago so would like to install it ourselves. It's an MBC timberframe with wide insulated walls, cladded/rendered on the outside. We can handle making the necessary holes in the walls. Is this doable, or should we get it professionally installed? Any suggestions as to type/make/model to choose? What else should we consider?

@Temp - thanks very much. I will reread said invoices and see what I can do!

Ahh, I suspected as much. Thanks both

Thanks Vivienz. Some (a lot) of these invoices are zero rated, but not all, perhaps because our connections were somewhat complicated! I wasn't sure if it was worth putting these in my VAT reclaim - I guess not.

I've tried several times over the last few days to call the 'National DIY Team' at the VAT office to ask them some questions about our VAT reclaim. Plus, the form says you have to ring them to find out what address to send your claim to. However, after all the autoattendants, I get a message saying basically 'sorry we're too busy to speak to you, please try later' and it hangs up. No option to hold, no answering machine, no other way to contact them. Somewhat annoying. Anyone else experienced this? It is just the time of year?

Can you claim the VAT back on building control services? I'm thinking not, as they're probably classed as non-claimable along with architects etc. ... (Sorry to do another post, I'm trying to get my posts up to 10 so I can see 'The Thread'!) Thanks in advance ?

Hello all, Can you claim for your gas and electric connections? (I'm posting partly so that I can get my posts up to 10 so I can see 'The Thread'!) Thanks in advance ?

We have been living in our new MBC-built passiv-standard house for the last 4 months. We have gas-heated UFH downstairs (in the slab), electric UFH in two of the bathrooms upstairs and an Airflow MVHR system. Having come from an old, standard-build house we were concerned about heating this house; we had no need to be. As I read previously on this forum, we spend more time figuring out how to keep the house cool than we do keeping it warm. Our 'leap of faith' decision (based on MBC advice) to have no heating in the bedrooms has been justified. The downstairs UFH, set to 21 deg C in most rooms, rarely comes on. Even in October/November, before we had any heating or MVHR on in the house, it was a pleasantly-warm 15 or so degrees inside the house, day in, day out. We have no heating in the bedrooms, just what comes from the sun and the MVHR, and it's maybe a degree or two cooler in the bedrooms than downstairs, which is fine. When it's sunny we have to close the blinds on the triple-glazed south & west-facing windows and/or open the Veluxes otherwise it gets too hot, even when it's around 10 deg C outside; the MVHR captures and re-uses an amazing amount of the outgoing heat. (We were warned that we had too many windows on the west side; they were right, but hey, we like to be warm, and our MVHR has a cooling add-on for the summer if we need it.) UFH is certainly much slower to take effect than radiators, and there's no nice area on which to warm your feet/back. But I would much rather have the even, fresh heat of UFH + MVHR than radiators any day ?

@lizzie That's a really good point about the handle, thank you! We haven't quite decided our reveal depths yet so will make sure we take this into consideration. I remember when fitting blinds to our current house I completely forgot about the handles (doh). Good luck with finding a solution, I will watch this space with interest

Morning all! I love this forum, it's become our 'go to' place for sensible information about self building. I hope I'm posting this in the right place, please let me know if not. We will be living on site in an old static caravan during our MBC build. It's in place, we have electricity, propane gas and sewer connections, and we're currently getting water via a hose pipe from next door's outside tap when we need it. Our 'temp to perm' water connection is due shortly, as is our BT phone connection, so we will be good to go, in theory ... However, how do we get the water and the phone line to the caravan? Both come in at the front of the plot, and the caravan is at the back, about 40 metres away. The electricity gets there via an armoured cable laid on the ground along the perimeter of the plot, can we do the same with these? Or do we need to dig a temporary trench and bury them? And/or some ducting? If ducting, can we put them in the same one? Thanks in advance.

We're getting an Internorm big slider in our main open-plan living room. Some of the windows in the room are too big for the Internorm integrated blinds so we're probably going to have separate blinds on all of them (so that they match). The problem we ran into was that normal roller etc blinds don't go more than about 2m wide and our slider is 5.3m total, which means I want two blinds about 2.65m wide each. We found that Luxaflex's Duette blinds can cope with this width and look really nice. They are about 25mm wide so the plan is to fit that extra-strong type of plasterboard above the windows and leave the battens off so that the blinds can disappear into the gap when they're open and when they're closed they will still be 'inside' the window reveal. We'll reinforce with aluminium or something if it looks like it needs it. It won't look as nice as having fully integrated blinds or blinds fitted into the inside of the window frames like in @PeterStarck's picture but we think it will look OK. That's the plan anyway, will be following this post in case someone has a better idea!

@Bitpipe Please can you share details of your letter box and where you found a passive cat flap? Just finalising details of our passive standard house and would really like both!

@lizzie thanks for the welcome and for your excellent advice! Much appreciated. We'll be living on site in a caravan (oh joy) so will be very close to the action but yes of course things will go wrong. We will be vigilant and learn as quickly as we can. Good luck with your windows and hope you get to move in very soon!

Really interesting post everyone! We're about to commit to MBC Timberframe and are just checking up on them so-to-speak. I haven't found a bad word said about them yet, and Derek/Lizzie the solution you've got for finishing around the perimeter looks great. Thanks very much for posting details, we will most likely do the same. Can I be cheeky and ask which windows you chose? We're going for the same look as in these pics and are interested in other people's experiences of window firms ...