Stones

Well, another warm day for us (forecast wrong yet again), but another interesting test of the house. Last night we reduced internal house temps down to 22C. The MVHR summer bypass remained on overnight but did nothing other than maintain that 22C. Through the day, we left all the windows shut and curtains and blinds open. Ambient air hit 23C, but skies were clear and the sun was shining brightly. Internal air temperature peaked at 24C again, which we have now reduced back down to 21C by cross ventilation. Two interesting things about today's performance. First that the internal temperature rise was only 2C, which given the amount of sunshine we had, I'm quite surprised at, and secondly, how little impact drawing internal curtains and blinds has on controlling summer gain yesterday, which was comparable solar gain wise. Drawing curtains / blinds certainly has a psychological effect - the shade / darkening makes you feel cooler, but in our case, not much practical effect. Cross ventilation works but does rely on two things, lower outdoor temps and a breeze to help with the chimney effect. Clearly, if we wished to control solar gain before it enters the house, we could fit film as others have done, but I'm reluctant to do so given the benefits we get in winter from solar gain, and how infrequently ambient air temperatures reach the dizzying heights of today and yesterday. Activating the ASHP cooling function is next on the agenda, but with several days of overcast weather and 11C - 12C ambient temps forecast, it's going to be a few days before there is any point doing so. One small footnote, my understanding is that PHPP modelling only considers internal air temps of 25C and above as overheating / there being a cooling requirement. 23C is my target maximum.

I recall something similar. I was of the understanding that we needed constant baseload to iron out the peaks and troughs associated with renewable generation, which by its very nature is variable. I seem to recall significant concern about this when Longannet Coal Power Station was closed and the impact it would have on the Scottish grid stability. Is the difference in frequency shown in the graph +/- 0.05 significant in how the grid operates and the effect it has on us as end user?

@ProDave We had mature trees that shaded the south west facing glazing in our last house -very effective they were too, sadly not something I have any hope of recreating up here. @Frogeye how long did it take before you noticed the cooling effect - hours? I purposefully left ours off to see what the worst case scenario would be (given the rarity of such a high temperature where I'm located). Back to normal ambient temp wise for us tomorrow so solar gain becomes useful once more.

http://www.bbc.co.uk/news/business-40058074 When I heard this on the radio, the thing that jumped out was the comment that the National Grid was paying companies to use electricity at times of peak (wind and solar) generation so it could manage what was being generated. Wouldn't it be nice if domestic consumers were offered the same...

With temperatures hitting 25C today this has been the first real test of our house in terms of overheating and how to manage excess heat. When I designed our house, I crunched the numbers, taking into account average and peak daily solar gain. Due to the large amount of SW facing glass that we have, I knew we were going to have some overheating, based on maintaining an internal air temperature of 21C. My number crunching indicated that summer overheating resulting from solar gain could be managed by means of the MVHR summer bypass, and opening a window and ventilating with cooler ambient air, and where appropriate, using blinds or drawing curtains. Up until now, ambient air temperature has always been several degrees lower than internal air temperature making it very easy to control how much of that solar gain we wished to retain. In practice we haven't had to do much in the way of control, as internal temps have not exceeded 23C in the main living areas, the bedrooms remaining 1C cooler as they are on the north side of our site. Today's challenge was how would the house perform without any cool ambient air or active cooling (albeit I do have the capability to cool our slab). I'll be honest and say I was quite concerned, but I'm glad to report that internal temperatures remained lower than external, peaking at 24C in the living areas, 1C cooler in the bedrooms. As ambient air temperature fell to 21C late this afternoon, the summer bypass kicked in and began to ventilate cooler ambient air inside (interestingly, when ambient air was higher than internal, the bypass didn't activate) and I opened two windows, one on the ground floor and the velux on the 1st floor mezzanine to create a natural draw through the house to purge some of the warm air out. This worked brilliantly and rapidly reduced the internal air temperature down to 22C, and shows how effective this method of control is. How did everyone else fare today?

How about a walk in fridge / cold room? http://www.coldrooms.net/case-study/domestic-walk-fridge/

http://news.bbc.co.uk/1/hi/uk/2749659.stm

Didn't they deploy armed troops in armoured vehicles around Heathrow a few years ago?

A warm welcome to you David. What type of house / style are you thinking of? Plenty of advice and experience on here, and plenty to read as well. The blogs are well worth spending a bit of time going over to give you a flavour of what you are letting yourself in for!

Indeed, although a victory for political self interest is probably closer to the mark...

Yes - taped and filled / decorated after. I did take the precaution of removing all of the doors / drawers whilst this was being done.

A few comments so I'll answer the LED ones first. @Nickfromwales @PeterW @Barney12 @Onoff I initially bought a couple of samples to test for myself - i.e. run for 8 hours to see if there was any issue with overheating or radio interference. Satisfied, I then discussed with the electrician, who tested them and was happy to install them. Can't comment on the results others have had when testing other electrical equipment, but I'm satisfied on the basis of my own and the electricians input. The lights have milled aluminium casings and inset diffuser lens, which provides an initial solid barrier to flame, although I've not fire tested a fitting yet to see how long it would last. Our installation is perhaps a little different as although the majority of lights are fitted to a ceiling where the 'room' above (mezzanine study) is open to the main living area, just as the kitchen is. The remaining lights (over the stairs / upstairs) have no rooms above and are simply fitted in the service void. Our main reason for fitting them in the kitchen was asthetics. @Crofter Looking at the driver, DC output 15 - 28V I first saw the idea (recessed bank of larder units) in one of the builders houses, and simply extended the idea to frame that run of units. I'm pretty sure we'd also seen some pictures in brochures as well. We had initially been thinking about a straight run of larder units on that wall, but decided that we wouldn't have enough worktop space if we did that and settled on the design you see. Partitions / framing were built around the units, so the kitchen units went in a lot earlier than would normally be the case. A 5 mm fillet of timber was fixed to the outside of the units to create a shadow gap between the partitions and units.

Given we have MVHR, I don't see the CO2 detector as anything other than a waste of money. My proposed alternative was simply a way of getting some useful benefit from it. One of those things I had to fit to get my completion certificate... Can't say I've noticed any issues in terms of shadows / not illuminating part of the area beneath the coomb ceiling. We fitted the lights in our kitchen (12) and its like Blackpool Illuminations when they are on!

Working around the joiners as they completed the internal fit out, the electrician returned to complete second / final fix. I won’t bore you with endless photographs of sockets and light switches, but will describe the most notable electrical installations: LED lighting – after obtaining various samples and some electrical testing, I purchased a quantity of slimline 6W recessed fittings from https://hartingtonheath.com/product-category/led-recessed-lights/non-dimmable/ I bought mine via their ebay outlet which gave me an additional 10% off. The electrician was a little dubious, primarily on the issue of the cut out size required being greater than a standard downlight. We went ahead and fitted them in the kitchen, utility, staircase and upper floor. Each light comes with its own driver so to wire up to the mains, a connector block enclosed in a 'choc' box was used. This did increase the amount of time required to install each fitting, but the actual cost of the fitting was significantly lower than the more traditional alternatives we had previously looked at. The light they give off is fantastic and they really do seem to disappear into the ceiling, far more so than many standard downlight designs I’ve seen. Apologies for the quality of the pictures! The slimline design was especially helpful when fitting in the coomb ceiling as there was no requirement to hack into the insulation as the fitting sat comfortably in the service void. Chatting to the electrician, he commented that they had now adopted this type of downlight because of the flexibility it offers. Our next luxury was a 5A lighting circuit - fitted in the main room so we can switch off all the occasional lamps used from a master switch. Simple, effective home automation! To future proof the house we installed Cat 5E data points to every room, with the hub located in the meter cupboard next to the BT master socket. I've located my BT router there and currently hard wire direct from an ethernet port on the back of the router to the port on the hub for the data point in use. There are still 2 ethernet ports left on the router, however, if I want to make any more than three of the data point live, I'll need some additional equipment (not really sure what would be required so following various current topics with interest). Whether we end up using all or indeed the majority of the data points, I have no idea, but it certainly made sense to put all the cables in. The last electrical item of note was a CO2 detector – a wonderful (Scottish) building regulation designed, I think, as a way for large developers to avoid having to fit a mechanical ventilation system, because householders have a means of monitoring air quality and therefore a way to manage it – by opening windows etc. At £200 they are not cheap (but from a developers point of view, a lot cheaper than an MVHR system). Here is the link to the relevant requirement - look up part 3.14.2 http://www.gov.scot/Topics/Built-Environment/Building/Building-standards/publications/pubtech/th2015domcomp No doubt this regulation will creep in elsewhere in the UK. I did have quite lengthy discussions about whether we could use a CO2 sensor in the MVHR to actively manage our ventilation. The idea of doing so was certainly very positively received and thought to be a far better / more sensible approach, but unfortunately, there was no getting round the installation of a stand alone detector as the Vent Axia sensor that you could integrate with my MVHR didn’t have the specifications required in the regulations. At £350, it was also significantly more expensive. If you read through the specification, you’ll notice that one of the requirements is that the sensor alarm must be capable of being switched off, which does make you wonder, why bother? Next entry: MVHR final connections and commissioning.

Well done on a successful pour. Hopefully the ICF pour goes as well. Details of our pour here:

We went through the process of comparing bamboo and oak samples. Certainly from the tests I put the various samples through, bamboo was more robust to things being dropped on it, but scratched the same as oak. We opted for oak as we preferred the appearance of oak over bamboo. We have been in a couple of houses that had bamboo and it was fine in those surroundings, but not the look we were after. You can get cheap oak, but it only has 2mm wear layer so other than localised repair (gentle sanding) not ideal for refurbishment. We opted for 3mm wear layer (14mm boards). We had a little damage (scratching) caused on move in day, not by the removers, but by the kids dragging a small footstool around before the furniture pads went on. No doubt there will be various dinks as time passes but this adds to its character (or so I'm told...). Prices do seem to have risen over the last few months (by £6 / m2 in the case of the supplier I used!)

@PeterW In my last employ, I had to have various such authorisations in writing, and they were all printed on my warrant card. In my current employ, the same applies, printed on my ID and in my contract.

They can: http://www.legislation.gov.uk/ukpga/1990/8/part/VII/crossheading/rights-of-entry-for-enforcement-purposes and in Scotland: http://www.legislation.gov.uk/ukpga/1997/8/part/VI/crossheading/rights-of-entry-for-enforcement-purposes Any person duly authorised in writing by a local planning authority may at any reasonable hour enter any land— (a)to ascertain whether there is or has been any breach of planning control on the land or any other land; (b)to determine whether any of the powers conferred on a local planning authority by this Part should be exercised in relation to the land or any other land; (c)to determine how any such power should be exercised in relation to the land or any other land; (d)to ascertain whether there has been compliance with any requirement imposed as a result of any such power having been exercised in relation to the land or any other land, if there are reasonable grounds for entering for the purpose in question

I masked up our windows (polythene taped to the frames) and when the wind speed was high, I observed the effect you describe, polythene inflated on windward side, sucked to glass on leeward side. It really does highlight how much of an impact high windspeed has and the potential for wind driven heat loss. Hopefully the plasterboard will dampen any related noise down.

I've been looking at acrylic, but SWMBO isn't keen. What appealed to me was being able to get it cut to size, including cut outs for sockets for 1/4 of the cost of coloured glass.

That's certainly the way ours works (Vent Axia). Does seem a very odd way of configuring it...

@Crofter IIRC, the idea behind the passive house heating requirement was to enable the delivery of what heating requirement there was via an inline duct heater, i.e. heating the supply air. Hopefully that gives you a starter for ten re heating capacity, and as you say, given that the build will mainly be occupied in mild or warm weather, something that could fit the bill.

Appreciate that a plinth heater isn't an elegant solution which is why I'm thinking an inline electric duct heater might be the best of both worlds. Easy and cheap to install, easy to control (room thermostat) and would distribute warm air to both your living and sleeping spaces. Nothing visible for your guests to see other than a wall mounted stat.

Cant disagree with that. What you have to keep at the front of your mind is that this is a holiday let, and all guests will care about is that it is warm and cozy. They are not going to care how that is achieved, and the simpler / more automated it is, i.e. the building is always at a constant temperature so they are not having to fiddle with controls, the better.

I think your good lady is right. I think UFH would be overkill and a waste of money. How about a duct heater for your MVHR instead, coupled with the towel rail in the shower room and a plinth heater in the main room for instant boost heating? Duct heaters circa £200. Set the duct heater on a simple thermostat. One of my former neighbours uses a duct heater and two electric radiators to heat his 250m2+ house without difficulty. I'm sure that would be more than enough for your place.