ragg987

Currently I am with BT and feel exactly the same - we pay a premium for Fibre and get crap back. I wonder if there are failings in the infrastructure given the fast expansion in recent years? I also suspect the cheapo routers provided by the big names play a role in the instability, and a good third-party router might help. I guess Freesat would be an obvious choice for your live TV, might require a satellite receiver / decoder if your TV does not already have the capability. On-demand would still require a good internet connection.

VAT reclaim should be straightforward, just enter the GBP equivalent of the 25% in your reclaim form. I attached a currency conversion screenprint to the invoice to show how I had arrived at the GBP figure. The converter allows you to set the date you want the conversion for. https://www.oanda.com/currency/converter/ I did a fair bit of purchasing direct from Europe, reckon i saved many thousands - primarily lighting, sanitary, some glazing and a few other bits and bobs.

That's it, good find.

Would your insurance policy be valid under this circumstance? You have a duty of disclosure and our policy has an exclusion clause relating to substantial building works. I cannot recall for sure but something along the lines of less than £5,000 of build value.

Yes that is the one we used. We needed a lot so purchased 2.5l tins much cheaper from buildersoak.co.uk Sanding first then vacuuming and wiping is essential in my view. Osmo chap told us to sand and said to use medium grit not too fine. We did not sand between coats.

+1 Osmo polyx. Been on for 10 months and still looks great after a mop down. Suggest you get hold of their floor cleaner to avoid drying out the oils. After we completed it I came across some website where the person had thoroughly tested a number of products for wear, finish and ease of use. In his view Osmo was not great. Matt or satin is very much a personal thing. We went with 3032. Also might want to use their brushes, they were much better than some emulsion brushes had.

The only issue we hit was standard house insurance and changing mortgage, both required BC. The rest no one seemed to be bothered.

Towel rads etc are all heat contributers, so just become a part of the bigger picture. In a low energy house they need only run for a short time (e.g. timers) and at a low setting. We have UFH only downstairs and it can get about 3C cooler upstairs (i.e. insufficient heat rises despite no insulation in the FF ceiling) so we rely on the towel rads to keep the bathrooms warm. Jeremy's experience is the reverse so there are other factors at play here - we both have the same MBC construction. Driers create two issues - heat output is one and what to do with the extrcted water is the other. In a sealed house, the drier ought to be a condensation type. We hardly ever use ours because... Having a MVHR creates a good environment for an internal drying line - we have a ceiling caddy thing in our utility room which has an extract point for air. One downside is that drying clothes inside the house removes some heat (I recall a discussion about it being something like 1 or 2kWh per load - don't quote me on that) so this means you need to add the heat back into the house through UFH.

I did both as well. BPC provided a template for MVHR balancing. For water consumption, I found an on-line calculator and just picked my equipment from the drop-down lists (or nearest equivalent). http://www.thewatercalculator.org.uk/default.asp Number of occupants is also required to drive the calculation. A tip - if you have multiple taps or showers or baths of the same type you need only enter them once, the calculation is then driven by number of occupants.

Looks great. And meadow grass = low maintenance, can't go wrong.

Nice. Miele have an outlet store near Oxford. I do like some of their appliances - wouldn't hesitate to get their washing machines. https://www.miele.co.uk/domestic/outlet-2991.htm

Enjoy, keeping dry for a few nights. Was a heavy one Thursday night. Somehow we moved to Tequila slammers !

We have an open plan kitchen to stairs not too dissimilar to this. Not a peep from BC, we ensured we showed heat and smoke detectors in the area. I agree about avoiding your primary habitable orientation facing North or East. If you have the space maybe have a detached garage? This would raise build cost a bit.

Aha - engaging brain. Your 3.5W/m2 is your actual reading, my 9W/m2 is theoretical PHPP calculation at design temp. Apples and oranges.

The weather compensation and set-up flexibility in the ASHP is miles ahead of what I saw in my parents' Vaillant gas boiler with rads. That system tended to over-shoot or remain too cold if a lower compensation curve was selected. I like it.

Yep - enjoyed that, @Nickfromwales. Context is everything. I think all this theory is one bit, but the most important bit is the result - is the house comfortable and is heating performing efficiently? The first question was an 100% yes last winter, the second one I don't know but hope to measure this winter as I have added a meter to the ASHP. I am astonished at @JSHarris's 3.5W/m2 requirement - a third of he PH standard, I thought we did well but goodness - is this your microclimate? We must have the same MBC construction with 300mm warmcell and u-value of around 0.1? Plus my house is larger so ought to have lower demand per m2. Dare I suggest your situation is not going to be so representative for us mere mortals?

I do have a room stat, but it does not directly switch the flow on or off. The control is through feedback. The stat set temp is the target from controller perspective. It them compares actual room temp, external temp and compensation curve to decide the UFH flow temp. So all else being equal, an increase in room temp above set will reduce flow temp. In my view this is better than any on/off mechanism that a traditional stat would provide as it is fully adaptive. The Hitachi also has an option for a fall-back mechanism - if room temp goes too high above set it will stop the flow (though like Jeremy I have my circulators running on a timer to passively equalise the slab). Here is another example (based on real observation last winter). External temperature drops suddenly from 10C to freezing. House starts losing heat quicker than before so HP needs to increase flow temp. The need for that increase is not immediate - house fabric has maybe 6-10h decrement delay (my estimate based on 10-12h for MBC fabric plus perhaps 1h for glazed portions). Plus slab will take maybe 3-4hrs to pass the effect of hotter water to the house. So I need to delay the ramp up of flow by perhaps about 5h so that I can pre-empt the impact of the cold snap and keep the air inside the house at a constant temperature. I have set the controller to react to external temp based on average of the last 6hrs. This has the effect of delaying the flow temp ramp up so it is gradual and the peak is delayed by a few hours. Perfect closed-loop? I think we are looking at very different principles hence we are apart. I am looking at heat-input balancing heat-output based on controller providing infinite flow temp adjustment. The alternative of on/off is a different approach. Neither is right or wrong, imo. I agree with your comment that my house is capable of absorbing heat as the HP provides it - that has to be the design objective, every house WILL lose heat when external temp is lower, it is just a question of degree. Background might help: 330m2 house, theoretical demand 9W/m2 (3kW if -4C outside), <0.6ACH@50Pa as tested. My HP is a 3HP unit (notional 7kW output). No UFH upstairs but option to heat upstairs only via MVHR (which we needed last winter). I expect that 99.9% of UK housing have higher heat requirements. If my dwelling were smaller I would choose a smaller HP. Agree I have been loose with the terminology, you have described it better than than I can.

This is indeed a challenge. In our case, I have decided it is best to keep the heating on 24x7 and let the environmental conditions determine the flow temperature. In your example, the 0.1C increase in room temperature would be fed back to the Hitachi controller which would compensate by dropping the flow temperature a tiny bit, thus reducing the heat fed to the slab. Of course the room will continue to heat as the slab change will only impact the room a few hours later, however we are then reliant on the thermal mass of the house to try and steady the impact of instantaneous changes in conditions. The same issue happens when the sun shines into the room on a very cold day. Solar gain is tremendous, room temperature will increase quickly. The only solution would be solar shading - I don't think any heating system based on UFH could compensate for this - we are then in the territory of air conditioning. @Barney12, I am sorry I have hijacked your thread way beyond the initial question you posed.

Not sure I fully follow the logic here. If the slab requires 1kW to heat the house and the ASHP can only modulate down to 2kW, then on average the system will need to be on 50% and off 50% of the time. This is regardless of the flow temperature - i.e. 40C or 25C - load is still 1kW. The only benefit I can see is that water at 40C holds more energy than water at 25C, so the frequency of cycling will reduce in this scenario and you would get longer burns and longer intervals between burns. However the potential downside is that heating water to 40C will be more inefficient (lower COP) than heating it to 25C. 90l buffer helps. Aren't we all! We do have a great community, inquisitive minds, and willingness to share and challenge. Long may it continue. And this is the primary attraction of the design for me!

You just reminded me - another reason I wanted to avoid a TMV is that it would be a single fixed flow temp setting. So if I set it for coldest day then on a milder day flow temp would be too high and system would have to cycle on and off or room temp would overshoot. Again, I am describing the theory as I understood it at the time but have learnt quite a bit about our system and the behaviour since then. At the moment I am fully at the mercy of the ASHP controller logic (which I quite like in reality - why reinvent the logic if a large company with millions to spend on R&D has already done it?).

I respect this and am just offering a counterpoint. You probably forget more about plumbing and heating every day than I will ever know ! As a FYI, the ASHP design I have was approved by Hitachi and falls in line with their installation handbook. Your point about failsafe may be valid, perhaps the black-box that is the ASHP already has something built in I do not know. Certainly there is a setting in there that allows me to set the maximum flow temperature, however I am fully reliant on the integrity of the controller.

Our Hitachi can regulate flow to any setting (through compensation control and heat curves - I saw it regulate between 23 and 30 last winter), though I guess if it is too low and there is insufficient demand in the slab that could lead to a lot of cycling given that minimum modulation is 30%. The buffer should help. I also use the buffer to preheat incoming cold water into the whole house (apart from kitchen). My plumber rolled his eyes at the idea, but after he plumbed it in said it was a great idea and why didn't all houses have it. So preheat is limited by heating flow temperature - typically about 25-28C, though as it goes through a coil then the impact of preheat is limited to perhaps 20 to 25C. I intend to create a post about our design at some point, but did not want to jump the gun and intend to run it for at least 1 year so I can comment on the reality.

Yes. So no blending at all in the chain on the basis that keeping the flow at the lowest setting gives best ASHP efficiency. While I have implemented this successfully, I have yet to prove that flow temp is proportional to efficiency. @JSHarris has measured his and suggests that COP remains the same as flow temp rises (I cannot recall the range of flow temperatures he quoted - something around 30C). I recently addded a power meter to the ASHP so am now able to monitor - once the heating period starts.

No blending required. The ASHP regulates the flow temperature. I have a 90l buffer to reduce cycling.

I can only relate our experience. One manifold is next to the pump in the plant room, it has more loops connected and serves 100m2. The other is in the basement and serves 50m2. I have balanced the inconsistent demands by twiddling the manifold flow knobs. Ground is fully open and basement is partially throttled. It works. I believe largely because of the very low temp flow and gentle heating possible in a low energy house.