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I will counter the above with my positive results with a modern well insulated house and an ASHP. The annual electricity used by the ASHP to heat the house is £400 at todays high electricity price, but it would not be a lot cheaper if we had mains gas available (we don't) Factor in the gas standing charge and they would be about the same. Fuel costs of all types is rising quickly, so the best thing you can do whatever heat source you choose is insulate the building to death and make it air tight with an MVHR ventilation system. And install wet under floor heating so if you do choose a gas boiler now, you can easily swap to an ASHP at a later date. AS much PV as your roof will take or as much as your DNO will allow. Then having an ASHP makes it easier to self use more of the PV you generate. If you do choose gas, choose a system boiler with an unvented hot water tank. That will allow you to dump surplus PV not being used to hot water. The very worst thing you could choose is a combi boiler.

Go Gas Boiler with PV - but with a caveat. I'll give you my thoughts based on my personal home situation and my professional observations (we have the gas/ASHP/PV/Sunamp debate for new buildings weekly). I have PV and a gas boiler, the boiler is relatively cheap to run, its not even a year old (I made the call to replace with gas and not go ASHP last Feb). On a crisp bright winters days I can also heat some space I am using with some small electric heaters, for free if I want. For example I am looking at electric UFH for the bathroom and adding an electric option to my office and maybe loft room so I can make use of day time sun for heat in the room I occupy most, I can whittle away at my energy import and balance things out a bit through the year. I then have the gas boiler for the simple hot water production and on demand space heating when needed. I am currently working on building services designs for a 4 residential developments ranging from 7 storey flatted development in London to smaller blocks of flats in Glasgow and a house, some will be gas boilers with a PV allowance per house, some will be ASHP some will be Sunamp's charged straight off the grid. When looking at heat loss for these flats or houses and the heating method we cringe at the cost some of them will cost to heat. The fact is electricity is expensive, things like ASHP's are expensive the whole lot will just be painful until electricity becomes cheap to produce nationally/globally. If it was me building from new, I would stick a gas boiler in, a hot water cylinder with a water coil and element fed from PV, more PV than I need, and electric heating options in various spaces, I would spend a bit more on insulation and try and create a building which needs little heat. I would leave in allowance in space and technical spec for more PV and battery storage when prices come down and my long term plan would be to lose the gas boiler, well, if that is the way things go, maybe we will see an alternative gas supply and boilers to suit, in which case I will be pleased I have the gas infrastructure. My thinking is that this will give me green credentials and cheap electricity to use however I wish, but the low capital cost of a has CH system but with options further down the line. If I go ASHP now, then to my mind, I have just signed away a lot of money on technology the industry is frankly still having trouble with, I also diversify my energy sources, I do think we are going to see more energy issues in the coming years, it could be gas or electricity shortages or sever price hikes. If you had told Germans 2-3 years ago, look boys you might run out of gas and struggle to keep the heat on most would have laughed, it is very real now. Which is why I am keeping my options open, it is why I have a diesel and a petrol car, at present my petrol is cheaper to run as Petrol is 20p a litre cheaper round here and my Petrol & Diesel get almost the same MPG. Spend some of the ASHP money on future proofing, make allowances for things you might install so you are sitting pretty and can, if you want, when technology and prices improve and maybe electric costs stabilise, go ASHP in the future. High temp versions are coming through now that will work as a direct replacement to a gas boiler without rad changes, maybe even increase panel size so that come slightly lower temps you still have good heating from them.

Plus the biggest washers you can find as plastic will just tear out over bolt heads if you don’t ..!

Really? That cabinet should have been a wine chiller or beer fridge, or an overflow wine chiller or beer fridge. And why would you want to play such a cruel trick on a kitchen fitter? Plumber maybe...

saw this article and wondered how many potential houses could be suffering similar issues if windows not fitted correctly. I appreciate its in America but could easily happen over here. https://www.greenbuildingadvisor.com/article/rotting-walls-in-a-sip-house?utm_source=Newsletter&utm_content=GBA+eLetter&utm_medium=Newsletter&oly_enc_id=6799F8366167I0Z

A short blog to show my Mini spilt Air2Air install, in the Windy Roost Static. I looked at installing a wood burning stove, but we have zero trees on site, so when I looked at the costs of twin wall flue, terminals, flashing, creating a heat shield and making the caravan tidy plus the hassle of getting wood / coal, the costs were adding up. A quick question on here - Build hub, some options were suggested and I decided to go with the a cheap Air 2 Air heat pump from Appliances direct. The unit is a Telefunken 12K BTU split unit. cost around £375 but did not included the pipe to connect from indoor to outdoor unit. I got 5M twin insulated copper pipe with the flair nuts from ebay for £56. Our Static has a gas fire - useless, and a chimney breast made from chipboard, the side panel just screws off to access the flue. This was the perfect place for the indoor unit, as it would be a neat install and the rear will allow for the pipes to be hidden, also I could use the hole in the floor to route the pipes/ drain and power for the remote unit. I removed the light fitting, screwed the bracket on the timber, and drilled a 80mm hole, for the pipes / drain and power. Then its a case of posting all the pipes/ drain and power cables through the hole, really straight forward, the indoor unit then just clips into place. The indoor unit comes pre wired with a 13A plug top, and you need to run a 3core and earth cable from the indoor unit to the outdoor unit. this is Live, Neutral and a control / switch cable. Next to the chimney is a double plug socket, so I wasn't messing around running new cables, I just drilled an 8mm hole in the side of the chimney breast and used 2M extension lead to plug the unit in. I used some zip ties to secure the extension lead and plug to the pipes (these were put on after the photo below). and that was the internal work complete. zero mess, and no rework / decoration required. The outdoor unit was going to sit directly outside, behind the chimney breast, the ground outside was not level but it is bedrock, so a made a simple frame and made level concrete pad, and cast some hook bolts into the concrete. For initial research I spoke with a Local (ish) refrigeration engineer, and he said he would connect for £120. but was telling me there is nothing to it, and if I was doing everything else then maybe I do it all??? I found an American You tube guide which was helpful on the pipework side. (linked below) Basically, the unit comes pre charged with gas, so you are not filling with gas etc. the main issue is removing the air from the two pipes you install. This is done with a vacuum pump. (some more expensive units come with pipes and they are pre-vacuumed with quick connectors) I found a vacuum pump and gauge set for sale on Vevor for £79 so £41 cheaper than the refrigeration engineer. I bought one, and an adaptor. I'm not suggesting anyone does this without an F - Gas Engineer, but the main issues are leaks, if when you connect the pipes up and they leak you are going to loose the gas, and the unit wont work. To Purge the pipes Step 1 connect your pump to the centre of the two gauges with a hose Step 2 connect a second hose to one of the gauges and the other end to the one way valve on the outdoor unit Step 3 Open the valve on the corresponding gauge from step 2. Step 4 Run the vacuum pump for 15mins to remove the air, and you check the gauge is reading negative. (-30 blue gauge in pic below) Step 5 turn off the pump and wait 15mins, and check the gauge is still negative. (-30) - this proves there is no leaks Step 6 close the valve you opened in step 3. Step 7 Open the 5mm Allen screws on both valves to the gas fill the internal unit. That is disconnect the pump plug the indoor unit in and you ready to go. Notes: I used expanding foam in the hole at the rear of the fire. We have no intentions of using the fire as it is /was rubbish. Also the indoor unit should not be near a source of heat. The total install time was around 4 hours. and total cost £530 More importantly my caravan has warm air. lets see what its like in winter.🤞

Results for us as they come forward...(and not what I expected) Our Cool Energy inverTech Air Source Heat Pump CE-iVT9 4.3kW-9.5kW has been on standby only, for the last few weeks, and I have measured the power consumption. It appears to use about 0.1 kWh an hour. That's about 2.25kWh a day in 24 hours. We use a Solic 200 to direct our excess electricity produced by the PV to the hot water immersion. Whilst the Solic way of heat the hot water uses more energy, because it only runs using power we would otherwise give to the grid, its better for the bills to turn the ASHP off all together rather than use it to heat the hot water tank. You would think that with a high COP it would be better to use the ASHP but with the other things on in the home and the car being charged, you can never be sure your not buying all the power. Secondly I think the ASHP runs at a minimum of about 1.5kW when heating the water. The Solic can use any spare power from the PV: 10 to 3000 Watts. We could turn the ASHP off altogether and on only when we need hot water and I have decided this is a bit fiddly so won't do it. Another benefit is the fact that the hot water tank is set to 70C ( the ASHP will only do up to 60 and that is at its least efficient) and this lasts us at least 2 or 3 days before needing to be heated up again! ( We do have a super insulated tank) Days when it could be cloudy and we would have to pay for the power. ( We will turn it up higher in the winter and use it as a thermal store for night time warmth...) And finally I would rather wear out the £50 immersion than the £3180+VAT ASHP! Good luck with your project. M

This is where I have been looking. I’m after the switch lite 8PoE. That’s still out of stock. I’d consider getting the 16PoE version, but it’s out of stock too.

I have the ASHP set to heat water to 45c between 6am and 8am.... This is on our low rate tarrif of 10p. Plus the PV is generating something. This is purely to ensure there's always water for morning showers. Rest off the time the Solic diverter heats the tank to 56c. I think the ASHP has been on only once or twice in the last week or so after I set this up- that was a day after lots of washing machine /dryer action and extra showers.

Hi chaps. Right it's zoot-liftoff time. I've plotted my ledger 7 mount positions, avoiding my perpendicular joist positions, & marked these 7 on the wall. But just thought is it best to mark my 7 upon my ledger > drill holes > offer timber up > drill thru to mark the walls? Maybe two sturdy rawl-plugged (temporary) screws into wall, to sit the timber upon.. get level > drill thru holes etc? I've done this plotted mount hole positions. Missing (9 total) joists @400mm centres. Mounts are 30mm down/ up, from btm/ top of timber edge. Comments welcome. 3220mm W. [I need to clear some furry guests away 1st mind you!].

The design for gas boiler is usually for a high temperature system. You can design it for a low temperature system (as ours is), but this totally confuses the normal plumper. But a low temp system is the same design broadly, the delta T can be the same for both a gas boiler or heat pump. Our boiler at 25 to 30 degree flow temps does so with a 4 degree delta T. Our heat load is low so the pipe sizes can be normal sizes. Most gas boilers in a low energy house will need a buffer to operate without short cycling, not just heat pumps. The trouble is to rejig the existing fleet of gas or oil boilers to run low temperatures; to get condensing mode all the time, a lot of homes would have plumbing of too small a diameter to get the mass flow through the system, at the required temperature. Plus they would need new radiators, new controller and a good possibility those with system boilers couldn't do low temperature for heating and high temps for DHW heating. So isn't a easy fix. Hybrid systems do work, but reducing heat demand is the real fix all.

I can't speak of the technical programming of the heat pumps themselves, but I think there's a big difference between what should be done and what is done in the market. To design a heating system using a heatpump or a gas boiler is exactly the same process if you want a properly designed heating system. As follows: calculate heat loss calculate hot water demand calculate total heat demand size heat emitters based on design temperature drop of the system and flow/return temperatures select your heat emitters based on heat factor and pipework emissions (this also varies depending on radiator connections) calculate system flow rate including pressure drop and flow velocity size pipework and pump accordingly (with heatpumps this might include the buffer) The differences between your fossil fuel boiler and heatpump is largely the flow/return temps and temperature drop across the system (which can be managed using a buffer in heatpumps) and thus flow velocity and rate. Using this method it's a fairly simple process to future proof the heating system for upgrade to heatpump in the future. The problem as I see it is that most installers doing gas/oil, don't bother to do these calculations, using rules of thumb instead which can be totally random. But with these systems you can get away with it because you just chuck in a big engine. Not so with a heatpump. I reckon if we rejigged all the existing fossil fuel systems we'd manage to save well in excess of 15% of gas, if not a lot more and have decently heated houses. Talk in the industry appears to be edging towards hybrid heatpumps using small heatpumps added to existing fossil fuel boiler or new hybrid boilers as a transitional phase.

Was looking to go fast track G99 route, with zero export inverter.

The Solic 200 that I have will only allow up to a 3kW immersion. We have 5.12kW PV installed. Wish I had room for 9.98kW PV ...... We could do it but we would have no garden left. M

I see that in your blog you noted that it could deliver up to 3kW. Is that the limitation of the Solic 200, or the solar setup - thanks? (I have 9.98 kWp of solar panels, and am working through options.)

Yes. Any brand will do in my book as long as it works. I think some can be connected to more complicated setups but ours is simple.

Yes.

First, I would get them galvanised or cancel and reorder galvanised steel posts. If it is all too late for that I would weld a cap onto them, then pour some thinners into it and swish around to degrease, then use something like Galvafroid paint or a good zinc chromate primer tipped into them, thinned a bit and swished, or get Dinitrol type stuff, swish it around until fully coated and tip out the excess. Let that dry. Then drill a vent hole, about 12mm (bigger on any side you wont see) just below the cap on each side, recoat with paint. Drill vent holes around the post about 100mm above what will be ground level, paint the holes. Sand and degrease the post and paint it properly, I would personally spray it with Etch primer and then primer it then 2k paint it, but DIY store products applied well will work too. First fill your hole with clean gravel and set your post, then backfill for the first 100mm of the post with gravel, this will stop the post just rotting out in damp concrete and let it breath. Then fill with concrete. That should last well. Thing to consider, when this post is cold and air temps rise condensation will form inside and out, this cycling over time can lead to the inside slowly rotting away, so internal protection from good paint products is a must. You do not want to seal the post at the bottom by concrete or a cap as moisture will run down inside and pool and the rot will start. Essentially you want to do the opposite of what may seem logical at first, you want it to breath. I have seen raw steel sit outside for decades and never come to any real harm past surface rust because the steel has been able to breath internally and dry out quickly.

No need to cap the bottom, the concrete will no rise very much. postcrete is great, I usually throw 1 bag in to get a hold of a post them when it’s firm use more to fill and poke/mix to behave more like wet pour

Hi, cap the top, no need to paint inside or fill. Do not wrap with plastic, let the concrete get hold of the steel. When concrete is set, mastic or silicon where post enters concrete and also slope top of concrete away to shed water. im guessing these are for a hammock or similar so not structural

Have you ordered them yet? You really want galvanised posts. Failing that, bitimous based waterproofing paint is appropriate. Cap it and don't worry about the inside.

No, under qualified fitters, not the industry as a whole. Entrenched ideas and philosophies are so hard to get rid of, I would terminate any conversation with a plumber that was negative about them, even if I was asking to have a combi boiler fixed.

Or..... Many years from now new owner decides to replace shower. Plumber takes up tray and says what a fantastic , incredible , professional job. Nick gets all the praise and not me.....

Best get it built before 2024 if planning gas! Scotland proposes 2024 new build ban on natural gas boilers - Heating and Ventilation News (hvnplus.co.uk)

The PHPP are annual heating requirements per square metre, so a good measure of overall performance but not something you can size the heating system on easily. What does the SAP say about maximum heating demand? And what is the overall SAP rating with the gas boiler and solar PV? Does it only pass SAP with the PV?

I hope it is in a sheltered spot? I was asked to wire a plastic shed that looked very much like yours but I declined the job as i had never seen such a flimsy shed before. I honestly don't think the one I saw will survive the first Highland winter.

https://www.screwfix.com/p/rawlplug-rawlbolts-m10-x-75mm-5-pack/20828 👍

It’s all a bit like my shower tray . Underneath on the supporting boards I painted “ @Nickfromwales was here ; buildhub.com “ . So when it leaks many years from now the plumber will know who to blame .

Generally right but I would take the board over the flanges to improve adhesion and reduce possibility of leaching or a potential crack line

Today I looked up the NHBC tolerances for floors. Shockingly tolerant. The 3mm over a 3m straight-edge is sensible and reasonable. But 20mm overall variation over 6m being acceptable? Therefore if you are worried about 10mm, as we all should be, then it seems you have to write our own specification.

Roundtuit has hit it on the head and good point / thread @puntloos Any competant builder knows that 99.9% of jobs will involve some changes at some point. Maybe a starting point is to put yourself in the builder's shoes when priicing / selling the job. Do you know much about the Client? Have they got a good reputation for paying? What is their personality? Do they listen to you and what kind of questions are they asking? When you seek clarity on say a detail.. how do they respond? If technical.. do you get a quick response from their design team? A lot of domestic Clients just won't do anything to help themselves here and this introduces uncertainty to the builder. If you don't know something just ask the builder and see how they respond, don't be embarressed. An experienced buildier when pricing up a job will often spot design / buildability flaws / opportunities for improvements. Do you tell the Client at this stage? You risk getting off on the wrong foot with the Architect / SE etc or just coming over as knowing too much.. trying too hard to get your foot in the door! In other words builders are looking for indicators on how smoothly the relationship will develop, if they get the job. Good relationships often = greater security on the expected profit margin thus a builder may be a bit less heavy with the "hassle factor" element of their price. If you go for the fixed price then have the conversation about making changes. The context is important. Again in the builders shoes. Say the price was based on two storeys with say a 30 -36 week programme and you turn round and say you just want one storey and the builder knocks off a lot less than you expect. Now the builder still has the over heads, needs to find other work and so on, hence not the price reduction you expect. The otherside is you ask for say a larger hot water cylinder that can be easily accommodated architecturally and structurally and the builder says this will result in a two week delay and the scaffold needs to stay up for longer.. daft example but.. have seen some daft arguements made in the past. One simple way is to say to the builder.. look I may want to make some changes that won't impact on the critical path of the job. Give me your day rates for the different trades and what uplift you want by way of profit on any extra materials you supply. Also give me the rates if we make a change that involves a bit less work.. if we say use a cheaper slate / tile or a larger tile (thus less of them) on the roof say. Ask.. will you knock off the difference or the difference plus profit? Just ask them innocently (no smiling) how this works and how they have managed this on their other builds. Best to get this out in the open early and then you can decide if this is someone you would employ. A good thing here is it lets you set out some ground rules / bench mark should you later want to make a major change, you can refer back to the early discussions, just make sure you have it writing somewhere. If you can, make sure you have a good understanding with you design team. Even if you got just a basic design, went for the cheapest to get you this far go back and ask your SE / Architect what they will charge to keep a watching brief, be at the end of the phone. It will be money well spent. Often if the builder knows that your design team are keeping an eye on things it can be enough to keep them in check. It can avoid both you and the builder doing something that in all honesty you think is ok but turns out to have a major impact on the structural or Architectural design. Common mistakes folk make are indeed moving a doorway / window, adding extra load to a floor / ceiling by way of extra plasterboard etc. You and the builder may look up and say, no change in the vertical load so ok.. SE may say.. I was relying on this to provide sway stabiliity (stop your house moving sideways) or restraint to a major load bearing wall. Architect may say.. you have breached the fire regs, changed the daylight, ventilation, compromised an access / activity space or some other clause in the building regs and BC are going to pull you up on this etc. Lastly you mention a fixed price contract. There is a big difference between the builders own contract and a recognised industry contract! The former is to be treated with extreme caution!

Think the problems may stem from a lot of monkey see monkey do, the trainer is giving a set syllabus and may not be that well versed in thermodynamics, have little or no understanding of when zoning is or isn't appropriate or the reason why. Or for that matter how to get a good CoP from a HP. Trouble is you can get away with a mediocre gas boiler installation and no one knows any different as gas is cheap. A mediocre HP install can have a bad CoP, electricity is expensive, so end with a big bill each month.

@Wil apologies just spotted your question - its jaga - my mistake. These are the ones we are going for, cheers https://jaga.co.uk/wall-mounted/strada

Got the blue key. £5 .

I'm currently trying to clarify whether or not planning permission is required for a flat garage roof. Have emailed the council, but no reply yet. I think as long as they are not meet 200mm height on top of the roof then this is permitted development, but that would require the panels to be almost flat, which is not good. You can now get through roof mounts, I don't have the link handy as I'm at work, they have a plate that screws to the existing structure, then a large piece of roofing membrane that's bonded to the mount, then once screwed down is then sealed the same way as your existing roof. This is what I'm looking to use, as I don't want loads of weight on our garage roof, the beams are not up to it. Many roofing manufacturers now accept the above mounts, and they won't invalidate their roof guarantees.

You dont need a smart meter unless you want to go for an MCS install and claim SEG export payments. Your "outside box" is your meter box. If you want to connect your solar inverter to the consumer unit in the man cave, youll need a slightly larger one to install another MCB for the solar inverter to connect to.

An interesting comparison to what others have said, but a very relevant consideration if maxing out on grid-tied PV. The OP may be in a better position due to the split arrays producing steadier all-day-long output vs a huge south facing array peaking at midday.

You seem to have so much stuff in addition to what's shown on the schematic! It really needs documenting fully. Is the Tesla CT hidden in the consumer unit perhaps? The schematic shows it between the CU and the utility meter.

I thought ST worked in a cafe, so intermittent.

My immediate thought was what a lousy kitchen layout if that space could not be accessed as a proper useful cupboard.

I went to 19.com. Wow, bookmark it.