Trw144

Looking further into two ashps. Anyone aware of any of the manufacturers producing a cascade controller -and potentially manifold as they do on gas boilers?

Some yes but not all as seemingly most of the demand is for heating the air, it also allows the pool heating to be kept more constant as opposed to overshooting target temperature, and then dropping back until the next day by simply using the pool as the buffer. December and January aren't great but outside of this you'd be suprised how many days solar generation can work in the U.K. (I have a 30m2 system recently installed that has created over 1300KWh in the last three weeks)

Hi Ali, I read you had a pool so hope you don't mind me picking your first hand knowledge... No, or this would have been my first (easiest) choice. Certainly not near some of the levels on this forum, but our current selfbuild (just under 300m2) has used 16,000 kWh for the last 12 months. If I can achieve a similar level of heat usage per m2 (excluding the pool), then I would be happy. I have never looked what my usage on a cold day is. This tallys with what heatstar have calculated , Do you know how this stacks up between a day you do and don't use the pool? One particular question I am trying to bottom out is how this peaks out and for how long. Heatstar have suggested a 20kW supply for initial heating of the water, and 10kW for the ongoing requirement (air handling and water). Do you know if it is important when during the day this runs as this would seem an obvious one to time shift (ie. avoid the late afternoon/evening expensive tariffs)? The Tesla tariff I like the look of (even without the car) as it currently equates to 11p/kWh for usage, but also the same for exports. As far as I can see, this is handy with a large PV system as it allows you to export your energy and then get it back when you need it at no cost. This theory doesn't work if they have some small print limiting your PV size/exporting? I also know two Powerwall installers who are customers of mine so hoping I could do some swapsies. My view on solar thermal is it works very efficiently for heating water (and is superior to PV and an immersion in this aspect). The issue for most people is they don't have sufficient hot water usage to make the cost worthwhile (ie. just heating a bit of domestic hot water), and stagnation causes issues. A swimming pool changes this and the ball park figures I have calculated suggest I could produce 60% of the pools water and air heating demand from solar thermal. For instance, I have recently installed a 30m2 system and many a day recently I have seen this churning out 15-25KW (I am planning on a system approximately half this size). Yes, I would like a buffer to act as a central heat source potentially for everything to run from., it would also work as a battery to store solar energy on a good day, for perhaps a day or two longer. I was initially thinking maybe a 1500-2000 litres. Having this buffer also allows me to consider running the heat pump overnight at higher temperatures on an agile tariff (reduced cop being more than offset by reduced electricity costs?). What does the inverter bring to the party on a heat pump? Modulation?

Yes, this is exactly what I would like to do my best to design out, and run as much off solar pv and solar thermal as I can. The pool water and air handling I had been looking to run from a combined unit (Heatstar) that produces both - they can cope with a flow temp of 43 degrees. I'm thinking as much as I am allowed so if I do go three phase, perhaps circa 12kW. Part of the design has around 100m2 of flat roof (although its not perfect as it will suffer from a bit of shading from the pitched roof next to it). My solar thermal supplier has suggested I could cope with around 16m2 of solar thermal and not cause a summer stagnation issue.

Yes the Hwam's are great - opposite of a Nestor Martin in so much as the autopilot does all the controls for you (primary/secondary air), but at the expense of being less controllable in terms of output (you wouldn't keep it in overnight for instance). The 4000 range is a very nice stove (used to have one in the showroom) and I think about 6/7kW nominal so more akin to your needs I would think. The convectors heat is channels around the body and top of the stove - not so much forced heat but natural air movement from hot air circulating (rising).

I need to start thinking about heating for the forthcoming build in advance of meeting the architect next week and dedicating some plant room space. I'm not 100% decided yet but would like some thoughts on an ASHP's route. I haven't done exact heat loss calcs yet, but house is 600m2 so its going to be a larger heat pump, at a guess something approaching 15kW. Thrown into the mix is an indoor swimming pool - which has a variable demand based on use, but requires a max heat demand of 10kW (much of which is to boost the ambient air temperature when the pool cover is taken off, rather than a constant 10kW). Current quandaries in my head.... Looking like two single phase units, or a large three phase unit installed with a large buffer (which will I plan on having anyway as I wish to install an abundance of solar thermal to heat the pool for free for as much of year as possible). Will also have PV (and possibly battery storage) but thinking this is unlikely to see an excess for water heating. Quandaries in my head on this approach... Should I go for a single large unit or two smaller units. At this size, should I GSHP - there is an acre of field next to the garden that could be used, and I have access to the kit to dig my own trenches. There will be a near identical house next door (without a pool) so again potentiall 15kW and could share the same ground loops. Should I design thinking about using an agile tariff and possible battery storage.

Can you get the smaller version of it over here? We were working on a TQ13 and TQH13 at the same time which would have used the 5kW internals. I think this would be plenty for this space. What about something Scandinavian styled? Hwam, Scan, etc. I have to confess a vested interest as I am still involved with them but I am putting the Lohberger Nobilus in my next build. Room sealed, auto closing door, and the option of a leather top, and also a Hwam inset 30/55. Edit - I have just looked and seen that Scan offer a similar looking stove to the Nestor Martin, but at a smaller output.

A little, we were the U.K. importer for 25 years and probably sold 100,000 + of them in one form or another. Great stoves - cast iron internals make them very durable, and they burn cleanly even when turned down low. Down side to this controllability is that you do need to know what the fire needs , so a little bit of learning to start with (ie. do you need primary air, secondary air, or both) I'm trying think back to the IQ33 - it was in development for about the 5 years prior to us exiting the market. The "plexus" control wasn't air tight at the time but they could well have worked on that since. At 9kW just check you can live with the output - stoves work better at a high output and you will much prefer to see a smaller output stove with a window full of dancing flames than a big stoves turned down constantly.

I would recommend using the fully bonded closed cell type of pipe (Calpex from Brugge or Rehau Rauthermex rather than the "onion" layer types such as Uponor (in the event of the latter, any damage to the outer casing can lead to water ingress along the pipe).

definitely, the swimming pool is saving you money ? I'm also thinking there are economies of scale in a 600m2 build that reduce the £/m2 cost.

The plus side to a basement is no expensive external claddings/finishes, and savings on windows (that's what I'm telling myself anyway!)

what is your floor build up above the void? Beam and block/concrete panels? We are also looking at a 200m2 plus basement with pool so interested to see what you are doing.

Has anyone stumbled across a product/finish like this in their research into metal roofs? We have such a large roof/wall to clad (16m long, two stories, plus gables) I am concerned the amount of seams is going to make it aesthetically "busy" on the wall facade. I very much like the finish this company does (a company called Lofthome who build steel frame homes in Holland) and translating their website does suggest it's pbx greencoat from SSAB. Without seeing the construction detail, my concern will obviously be water ingress between the panels... https://lofthome.nl

We are anthracite inside and out. I really like the look it gives and will be doing the same on the next build.

Combi boilers have to have a high output to produce hot water quickly for your hot water (around 30kW), which is going to be much higher than the output you need for your heating your house (which I suspect will be less than 5kW even in the cold weather). If it can't modulate (reduce its power) down this low then it will cause the boiler to cycle on/off/on/off which reduces its efficiency and increases wear on the boiler.

I have UFH with a gas system boiler and works very well. I certainly wouldn't revert back to radiators having lived in two houses now with UFH (on all floors). My only concern with a combi is whether it would modulate down enough for a low energy house - I'm sure others here will have experience/a view on this and chip in shortly.

Plus 1 for this

Not sure if it's the style you are after but the Lohberger H20 has direct air and a boiler (it's actually better than a back boiler as it's above the burn chamber so doesn't create the problems of cooling the combustion as a traditional back boiler stove does).

Yes, I remember having a quote for a Howdens kitchen many years ago that had a list price of about about 80k!!

Will note this trick for the next one.....

Yes the touch pures are expensive. I installed the one wire sensors inside the retractive light switches as the hidden solution. The air extension plug switches have a built in temperature sensor and are great for controlling lamps on the lighting circuit, but quite possibly you wouldn't have them in every room.

Yes I used those - don't remember them being £450 each but they may have been. Keeping to the Loxone products, it seemed neater and cheaper than having multiple dimmer extensions.

How is your heating controlled exactly - are they just open/close circuit sensors in the room? I've used Loxone one wire sensors in each room, so my heating logic is sat within my Loxone programme. Has allowed me to run weather compensates circuits (possibly not so important on low energy houses), with a 0-10v signal to my gas boiler of the required temperature (say 40 degrees if UFH running, 55 on my towel rail circuits which run for say an hour a day, and then max temp for hot water). PIRS are useful - we've used them in walk in wardrobes and cloakrooms to bring the lights on. Great not having to faf around with light switches when you are popping in and out of these rooms.

We used Loxone on our place and can recommend Dali for lighting - saved having lots of loxone extensions (which can soon add up to a lot of £££). Can you become a partner by attending the course or have they completely clamped down on the diy type market? Discounts weren't ever that much anyway (15% IIRC).

who was this with? There seem to be quite a few of us in the forum at present trying to find the most economical zinc/metal roof installer.