Jeremy Harris

I went around checking out stuff and found that my "normal" 24" hi-res monitor was an energy hog, even when on standby, and that tended to be left on a fair bit of the time, my old desktop PC was also an energy hog - over 100W a lot of the time. The PC problem has been fixed in the new house by building a mini-PC using a fanless kit, that has an SSD as the boot drive plus a 1Tb 2 1/2" low power data drive, that sits powered down most of the time. With a Kaby Lake Core i7 7500U processor and booting off a Samsung Evo 850 SSD it's reasonably quick, but the main advantage is that it rarely exceed 15 W power consumption, and idles at around 3 to 4 W much of the time. What I'm looking for now is a monitor that's at least 24", with at least 1920 x 1200 resolution, that uses a lot less power than my old Acer 243W.

Likewise, I spent hours effectively reverse engineering ours to find out how to best control it. I think much of the problems lie with these often being badge-engineered devices, with the named manufacturer not having in-depth technical knowledge of the product.

I went through the saga of having the ridge height checked for compliance with our planning permission condition. In our case, for the removal of doubt, ridge height was referenced to Ordnance Datum. If there is no reference point given, then arguably the condition is unenforceable. I think it's good practice to refer all levels to Ordnance Datum, just because it avoids all doubt and makes checking levels very easy indeed. A topo survey will always be referenced to Ordnance Datum, too, so that's often a handy way to get a relative datum that can be used for height measurement.

Thanks for the tips re: VOIP options, very helpful. I've made our internet connectivity tolerant of power cuts by running the modem, router, switch, file server etc from battery power. I did away with all the wall warts for power and made up a box that has a high efficiency 15V switched mode power supply, trimmed down to deliver a fixed 13.5V. This then charges a bank of 12V sealed lead acid batteries (about to be changed for a new large single cell lithium pack). I then derive the nominal 12V or 5V power for all the widgets from the battery supply using high efficiency switched mode DC-DC converters and run some of them via a crude PoE system, where I run power down the two unused pairs in the Ethernet cable. In practice this works well, even over 10 metres or so. As a safeguard against over-discharge, I have a latching relay and microcontroller that's set to detect too low a battery voltage and turn the load off, but this only happens after about 36 hours, which is longer than any power cut we've had so far. Being able to have the internet and LAN/WLAN running during a power cut is very useful, my main restriction now is how long the battery back up in the local cabinet in the village lasts during a power cut. I've not managed to find this out yet, but do know from experience that it lasts at least 4 hours.

It's all about area and the scale of movement though. The coefficient of linear thermal expansion for concrete is around 0.014mm per metre per deg C. So a 5m wide room would move around 0.07mm per deg C change in temperature. The range of temperature that our UFH heated slab sees across our widest room (about 5m) is at most 5 deg C, and that's the variation from floor cooling (18 deg C) to maximum floor heating (23 deg C). So our kitchen/diner floor moves about 0.35mm worst case, across it's entire longest dimension. The large format travertine we've laid is 400mm wide on that axis, so across each 400mm wide tile the worst case movement, ignoring the coefficient of linear thermal expansion of the travertine, is going to be 0.028mm. To give a sense of proportion, a human hair is around 0.025mm, so we're talking about that much absolute maximum relative movement, IF the travertine has zero coefficient of linear thermal expansion. Flexible tile adhesive has a maximum allowable "give" in shear of around 0.2mm to 0.4mm per metre, so around 0.08mm to 0.16mm across a 400mm wide tile, far more than enough to take up the relative movement 0.08mm per metre per deg C IF the tile had a zero coefficient of linear thermal expansion. However, no tiles have a coefficient of thermal expansion that's zero, they range from around 0.004mm per metre per deg C for porcelain to about 0.008mm per metre per deg C for travertine. Taking our travertine as an example, the actual differential movement is given by the difference between the two coefficients of thermal expansion. In our case, for the 5m long run of travertine, with 400mm wide tiles, the absolute maximum relative movement, between the floor being on maximum cooling to being on maximum heating will be about 0.016mm per tile, massively within the ability of the adhesive to flex, and far too small an amount to cause a crack.

All I can say is that it's not the case at all for our slab - no movement at all, not even a fraction of a mm, in the five years since it was cast. @Onoffs concrete was down a couple of years or so before being tiled, IIRC, and is also reinforced. Our old house had the slab tiled not long after it was built in 1986 and there's been no movement there, either, and that's not even a reinforced concrete slab, and the area by the front door get's very hot from sun coming in through the glazed panels. I can understand the problem with large areas in a warehouse, particularly given that they probably tile those places out before the slab has even had time to properly cure, but remain wholly unconvinced that the significant extra expense of decoupling mat is warranted on reinforced concrete slab that's pretty well cured before it's tiled.

If our reinforced concrete slab moves we're in BIG trouble, least of all will be the travertine laid directly on it! It's a question of horses for courses here. The low temperature differential, plus the reinforced slab, means there is zero risk of relative movement. A non-reinforced, non-structural screed may possibly move a bit. Both the two posters above and our own house have a reinforced concrete slab that isn't going to move at all relative to stone or tile flooring, but the same may well not be true for those using a screed that's non-structural.

The matting isn't needed at all for a modern, low temperature, UFH system with tiles laid on to a slab with embedded UFH pipes, as there will be zero relative movement from any temperature differential. The use of this matting harks back to the old days when poorly insulated houses needed UFH running at over 30 deg C in order to give enough heat output, so there was a significant temperature differential through the floor. No new build today, even one just built to meet building regs, is going to need UFH anywhere near that hot. The floor will get much hotter from the sun shining on it in summer than it ever will from the UFH. For example, it used to be that UFH installers would work on the basis of being able to get around 50 to 60 W/m² of heat from a UFH installation, sometimes more, maybe up to 80 W/m². That equates to a floor surface temperature of around 26 to 28 deg C for a 21 deg C room temperature, and a UFH flow temperature of around 30 to 35 deg C or so. No new build today is going to need that much heat, our house, for example, needs at the very most a floor surface temperature of less than 23 deg C, and there's no way whatsoever that 23 deg C is going to cause the slightest problem with relative movement - that's only 2 deg C warmer than the room. We never need a flow temperature that's higher than about 25 deg C, and that's only in the very coldest weather. I've measured floor surface temperatures of over 30 deg C in sunny areas in our old house, which doesn't have UFH, but does have tiles laid directly on a concrete slab and they've not cracked or moved in over 40 years.

Just manually change the range in the graph. Right click on the vertical axis and select "format axis". Select the "scale" tab and set whatever max and min you want in the boxes, then click "OK".

Sounds a very good option to me. In practice the accumulator will rarely get very cold, as when the house is occupied there will be a regular flow of water at around 8 deg C (normal mains water temp in most areas of the UK). The case you need to protect for is having a long cold spell whilst away on holiday and not using any water. I insulated the inside of our treatment plant shed, where the accumulators are, with 50mm of insulation, then added a 60 W tubular heater under the accumulators that is switched by a frost stat, so only comes on if the temperature inside the shed drops below 4 deg C. I don't think it's ever come on, as it takes a fair time for such a large volume of water to cool down.

I think it's reasonable to not include the FIT, and definitely right and proper to exclude RHI, but when doing this sort of calculation I think we do need to include any export payment, as that is energy going back to the grid for others to use. If I re-jig our costs to ignore the FIT payment, but include the export payment, then the figures are (including VAT): Council Tax = £2081.32 Imported electricity cost p.a. (inc. standing charge) = £436.69 (includes some winter electric car charging) Imported electricity energy p.a. = 2,445 kWh Exported electricity energy (deemed 50% of generation) = 2,493 kWh Exported electricity payment = -£130.63 (2,493 kWh * £0.0524) Net cost of imported electricity = £306.06 Water and sewerage = £0.00 Gas = £0.00 Floor area = 130m² Total grid energy consumption per m²/p.a (including partial car energy, excluding exported energy) = 18.81 kWh/m²/p.a. Total house (and partial car energy) energy running cost per m² (allowing for exported energy payment) = £2.35/m²/p.a. Total house running cost per m² including Council Tax = £8.05/m²/p.a Council tax makes up about 71% of our total house running cost, excluding the FIT payment. I can separate out the heating energy element from this reasonably well, as I have an energy meter on the ASHP supply, so I know that we use a bit under 12 kWh/m²/p.a. for space heating, but a small part of that will come from self-generation, so it's impossible to work out how much grid energy we use for space heating, or how much grid energy we use for everything else, including a bit of car charging. Worth noting that at least 80% of the hot water comes from energy we self-generate, plus quite a lot of the other house energy use comes from self-generated energy as well. Our energy use is heavily skewed towards the winter, with the summer bill being dominated by the standing charge.

As long as you use reasonably large bore pipe from the accumulator to the house then they will work fine. As you have such a small bore main, there is an advantage in getting them as far down that (in terms of distance from the house) as possible. Either 25mm or 32mm MDPE will be fine for the run from the accumulator to the house.

It's primarily about reducing energy use, which largely hinges on reducing energy loss, which in turn hinges on reducing space heating loss and, perhaps more importantly, reducing DHW energy use. In retrofit terms, heat recovery systems for hot water are worth looking at, especially for households with families that use a lot of hot water. You can get heat recovery units that fit in the drain pipes from showers and baths and recover around 70% of the energy used to heat the water initially, which can make substantial saving. @jack has one, I believe, and may be better able to give a view as to how well they work.

Ditra decoupling mat.

Best gadget I've ever made, bar none, is a dirt cheap Ebay bullet camera, fitted with a ring of white LEDs around the edge and connected to a length of cable, with 12V power connector and phone that connects to any video monitor, or an adapter that plugs into a PC/tablet etc. The number of times I've used this for checking things, helping to guide cables through hidden spaces, checked for things I've dropped behind things, etc, has paid the modest cost many times over. It has been so useful that I've even made up a cable reel to stow the cable on.

That's not unusual around here. I worked with people that paid that much or more. It seems mad, but it's a symptom of the vicious cycle of high property cost and the need for high family earnings to support it.

I really don't get the fashion for stone worktops at all. Every house we've ever owned, bar our old house and the new one, has had laminate work tops. I can't ever remember having any significant problem with them over the years, with the exception of the worktops originally fitted in our old house, where the person that fitted them failed to seal the joints and positioned one joint right next to the sink. Needless to say water got in and made it swell. In terms of the surface, all seemed easy to clean, durable and generally fit for purpose. I replaced the laminate in our old house with some laminated together double layer 18mm MDF, topped with ceramic floor tiles, and that's worked OK, but was a lot of work. The new house has Silestone, but it cost well over £7k, and frankly I don't think it's good value, but it wasn't my decision...

We also have a major problem with a the way people have had to move from North to South, creating a ludicrous situation where house prices and land in the South is unaffordable for anyone earning less than a small fortune, and rental costs are even higher, yet house prices and land in the North is far more affordable but there is a dearth of employment. Just fixing that imbalance would resolve a lot of our housing and employment problems in one hit. The South of England is NOT a great place to live or work. If I had my way we'd live in the Borders, or maybe even in the Highlands, where I'd feel right at home, even though I've no Scots ancestry (that I know of). Not my call though, SWMBO wanted to move back South; I didn't have much say in it...

Worth also contacting Dambat in Poland. They make some pretty cost-effective tanks of good quality and with ready availability of spares: http://www.dambat.com/diaphragm-tanks.html We've had one of their dirt-cheap borehole pumps in use for three years now (it was intended as a very cheap (less than £100)temporary replacement whilst we were waiting for a new Grundfos to arrive), If the Dambat/IBO pump failed now it would still have been reasonable value. Add in that I could probably fix it for the cost of a new impeller for £30, and their stuff starts to look like pretty good value.

We've been in the same position for years; the dominant house running cost is always the Council Tax (currently £2081.32 p.a. for each of our two houses, soon to be one, with luck). Our energy costs at the old house have never exceeded half that, so in relative terms, energy has never been close to being the dominating running cost. The other real killer down here are water and sewerage charges. We're reasonable frugal with water, but we still spend almost as much on water and sewerage charges as we do on energy. I'm actually pretty pleased that circumstances pretty much forced us into drilling a borehole for water and fitting a treatment plant, as, although both add to our energy usage, the overall cost is a tiny fraction of the price we'd pay for mains water and sewerage.

Personally I'm convinced that putting the actual last year or twos running cost in the advert would be more effective than any form of energy performance certificate. It's hard to ignore something that says "This house costs around £4000 a year to run" in the details, perhaps with a breakdown into Council Tax, water and sewerage charges and energy bills. As an example, the 3 bedroom, 1986 built, bungalow that (I hope!) we've just sold had an annual running cost of £3,877.28 a year (£2081.32 Council Tax, £969.96 gas and electricity combined, £826 water and sewerage). The house we've just built has an annual running cost of £1,601.12 (£2081.32 Council Tax, -£480.20 electricity, no water or sewerage charges).

The accumulators only have a single connection on the bottom, so normally have a tee on so that incoming water comes in one side and outgoing goes out the other side, with the accumulator connection coming off the top of the tee. For mains pressure boosting you fit a non-return valve (NRV) on the incoming side, so that the peak pressure gets stored in the accumulator. When connecting two (or more) together, you just run the "outlet" from one to the "inlet" to the next and they effectively work in parallel. The dimensions vary a bit, but the 300 litre ones I have are 630mm in diameter and 1400mm high. IIRC, they were around £300 each. The 500 litre one would have been fine for me, but was too big in diameter to fit in the shed I'd already built. IIRC the 500 litre one was close to being 800mm in diameter, and I only had around 700mm of room to spare inside the shed.

What then happens if you have a high water table (as we do) and you get the sludge pump in to empty the tank after a couple of years? That's when the damned things float up, when they've been pumped out during the two or three yearly service, and then sit virtually empty for a few days until they refill.

I wholeheartedly agree. When we were selling our old house recently (which is by no means energy efficient - it's the best I've been able to do to reasonably improve a 1986 bungalow with solid floors), I did print out all the bills, including the energy bills, and had them laid out on the dining room table. I also knocked up a single sheet with the total prices for everything per month and per annum (so energy bills, council tax and water and sewerage bills). I also had a copy of the (now mandatory) EPC printed out. What we found was that pretty much every potential buyer was interested in knowing how much the running costs were, no one was the slightest bit interested in the EPC band, which pretty much proves, albeit anecdotally, exactly what you've said. There were lots of comments along the lines of "That's about the same as we're paying now", or "that's a lot cheaper than our current house". Having a summary of the costs seemed to be useful, as few were interested in actually checking the bills I'd printed out, other than one or two that wanted to confirm the Council Tax band.

Just been digging out costs. I just remembered that I'd put together a simplified spreadsheet detailing our costs, which covers most things. It may need some work to relate the costs in it to the times above, I'm afraid. Simplified costings - 230421014.pdf