ProDave

What I was trying, very badly, to say, was lets say you are (wrongly) trying to fit a HP in place of an oil boiler that is driving radiators that need to reach 70 degrees to get the house hot enough in the depths of winter. I have heard it say something along the lines of "the heat pump heats the water so far and the oil boiler bit heats it the rest" That is the bit I just can't fathom because I just can't see it working. Or in other words, I hope people are not expecting to fit a hybrid where what they should be doing is modifying the heat emitters so they will operate in a temperature range the heat pump is capable of.

But surely most of that will now be collected and sold in the normal way? The practical effect is the forest has been harvested a bit before it was mature. Then it will be replanted. I can't see it just being left to rot.

Likewise we moved to a normal policy once we got a temporary habitation certificate. We went through the broker GSI also mentioned on this forum. We went through the broker due to the all timber construction so in some insurers eyes "non standard construction" and they never actually asked about a completion certificate.

it's normal to get a self build policy before you start, it can be harder part way through a build. Ours covered the building and the static caravan though not the contents of the static caravan.

This sounds very much like issues I had at the start with my LG ASHP. So there will be a flow switch to make sure the heat pump is seeing sufficient water flow. There could be 2 issues: There may be a motorised valve that opens when you get a call for heat and it is taking too long to open and the flow switch test times out before the valve has opened fully. The flow rate might just be too marginal so it is not triggering the flow switch every time. This was my problem and solved by fitting an extra pump to boost the flow rate. If there is an automatic bypass valve, try opening that a bit more to allow more bypass flow to help things along. Or save yourself the head scratching and just call the installer and say the system you installed a few months ago is not working properly.

The whole concept of a hybrid has puzzled me. What is the actual purpose of it and exactly how does it work? We know heat pumps work best at relatively low temperatures and relatively low power output. I am struggling to see just how adding an oil boiler can help that, without the oil taking over completely. About the only thing I can think is use the ASHP element for low temperature heating and the oil element for quicker and hotter hot water heating. but if that is the aim they would be better off as completely separate systems.

Yes, an island hood from Howdens, recirculating. I don't seem to haver taken a photograph of it.

Yes the blower in this case is sucking air out of my home made blower door. You then go round looking or feeling for air coming in through any leaks. A Joss stick (other incense sticks are available) is good for making a bit of smoke to see leaks. A telling thing if your air tightness is good, is the building will depressurise enough that if you go and open a door or a window you will get a big whoosh of air entering the building as you open that door or window.

It looks a nice site, and the floorplan layout is not bad, but the elevations give the impression of a design made to look quaint, but with no thought given to cost and complexity of build. I fear the present design is going to work out difficult and expensive to build while giving no obvious benefit over a simpler design other than looking quaint.

Grant were traditionally a respected make of oil fired boilers who relatively recently have branched into ASHP's and hybrid boilers.

That analysis seems to be over thinking it. Your HW usage will be what it is. The USP of a sun amp is and always has been smaller size for a given storage capacity (compared to water) and lower standing heat losses compared to a water tank. If one of both of those USP's justifies a sun amp for you then it is worthy of consideration. For me, what killed the idea stone dead was the PCM operates at too high a temperature to be charged from the relatively low temperature hot water from an ASHP so would have to be charged via a resistance heating element, so that's the electricity cost doubled then for me, which would kill all other advantages. There was talk of a different PCM that would work at ASHP temperatures. Did that ever happen?

I find it hard to quantify material rises last year. Most of what I was buying was timber, and it was not just the cost, but for much of the year timber was simply hard to find and it was a case of get whatever I could from whichever merchant had it. No chance to play them off against each other to get the best price when only one of them had it and they knew they were the only one.

Just how many elbows do you want and for where?

Not yet, but in view of the vast increases in the cost of living, I am on the verge of putting mine up 7.5% (it;s some years since it last went up) I can't be the only one?

At the start of our build BCO (only council up here) would come out at short notice e.g. for foundations, and were easy to contact by telephone. By the end of the build they were hard to contact, and took weeks to get an appointment. Now that may just be that a completion inspection is not urgent, and they may still go at short notice for foundations, but my general impression was the service was poorer than at the start. They also irked me with a stupid procedural thing. There were 2 very minor points at the completion inspection. Instead of just saying "fix those and we will issue your certificate" they issued a formal "refusal to issue completion certificate" meaning not only did I have to fix the 2 minor items, I than had to apply again for a completion certificate and wait the long delay for another inspection. If they are deliberately making the system clumsy like that, it is no wonder the service has got worse the amount of extra time it wastes for all.

But you will need a controller. The way UFH works is if one zone calls for heat from it's thermostat, then the manifold pump starts, it calls for heat from the boiler and just the actuators for that zone that needs heating are energised. I am not familliar with this Tado system but I hope it does all that, and if it is that clever can it not cope with one more valve for the towel rails?

You are over complicating it. It is just like any other 2 zone heating system. Just use a 3 channel programmer, one for the UFH one for the radiators and one for the DHW and wire it as any other S plan system.

It's not just cycling, there is nothing wrong with that and it WILL do that in mild weather. Short cycling is bad. In my case with a heat load of about 2.5kW at worst and a 5kW ASHP the HP only needs to run half the day to provide enough heat into the building. The rest of the time it is off. This is simply achieved with room thermostats. Once the rooms are up to temperature it turns off, and the house is so well insulated that it takes a long time to cool down to call for heat again, usually not until the next morning. I would rather have a heating system that spends some or even a lot of it's time off, than have one that is too small and does not cope with the coldest periods of weather.

Yes that is basically what we did. We lived in our old house (2 doors down the road) during the start of the build. The house was wind and watertight when we moved into the static caravan and that triggered paying band A council tax on it when we moved in. At that stage we had the laundry set up in the (very unfinished) utility room and an office space set up in what was to become the living room. That and the storage space the house shell offered, took some of the pressure off caravan living. We then concentrated on getting the kitchen / diner close to finished and the main bathroom close to finished, and 2 bedrooms plastered and painted. Then we started "spending some time" in the house while we built it around us.

It depends to some extent where you are? And are you living on site say in a static caravan or not? We moved in about 3 years before it was finished, but "officially" we were still living in the static caravan, it's just that we happened (cough) to spend some time in the house, because it was more comfortable than the caravan. A year before completion we regularised that with a temporary habitation certificate which you can get in Scotland from building control and completed late last summer. Being in the caravan and paying band A council tax on that meant we got the bins emptied and the address registered etc but in no way impinged on the VAT claim for the final house. Pre Covid the council tax surveyor was a regular visitor but when we actually completed I had to actually contact them to tell them to value the house, and they did that without visiting so presumably off the plans.

If the house needs a heat input of 4.9kW when it is -10 outside then that is 117.6kWh of heat into the building each 24 hours. Assuming the 6kW heat pump can actually deliver 6kW into the house, then it will need to run in heating mode for 19.6 hours in each 24 to deliver enough heat into the house. That will only leave the heat pump 4.4 hours to heat DHW so that is not going to be "bath after bath" That is barely adequate. Most people would want a heating system that keeps the house warm even in the most severe winter weather, so i would certainly not go lower than 6kW in this case. Yes the HP will work a lot less hard when it is mild, but all systems do that.

@Stones fitted some vertically at the same time as I did my ground mount system. Perhaps he will come along and say how they are doing.

Well your only options are internal insulation. What you have in the loft bit is so poorly detailed it is nowhere near as effective as it should be. Loads of air gaps for the heat to bypass the insulation for example. What is behind the plasterboard in the sloping bits? if that's not up to standard it could be a lot of work to re do it properly. It all depends how much time and effort you want to spend and how much disruption and making good afterwards you are prepared to accept.

I had to fit a second circulating pump to get the water flow rate high enough, that is in the house and is the one I can hear (though not as bad now we have carpet in the bedrooms) If the power drawn is high enough to measure, I wonder if as well as turning the pump on, it also turns on the electric heating element? I have never monitored the power while it is doing that. I know it does not start up the heat pump.