Duncan62 Posted April 2 Share Posted April 2 Hello, Beginner at loopcad but like to try, put me straight. Wall/Roof/Floor all ~U=0.11. Windows ~U=0.8 UFH loops to be laid and fixed atop the mesh in the insulated slab before the pour. I've tried to keep to 3 x 100m loops which will all operate on a single zone. Low temp batch heated over night by the ASHP. Top-up on coldest days in the afternoon. GF area ~110 sqm Annual Heating Demand is 1800kWh/a (11.4 kWh/sqm a) Heating load for house is circa 1.5kw (PHPP). Option to cool UFH water in the summer via ASHP. Link to comment Share on other sites More sharing options...
JohnMo Posted April 2 Share Posted April 2 Looks pretty similar to what I did. Put loads more pipe in bathroom. I would do as close centres as you can. Link to comment Share on other sites More sharing options...
Duncan62 Posted April 2 Author Share Posted April 2 36 minutes ago, JohnMo said: Looks pretty similar to what I did. Put loads more pipe in bathroom. I would do as close centres as you can. Roger, thanks. I may also put it under the shower tray in that case, greater area! Link to comment Share on other sites More sharing options...
JohnMo Posted April 2 Share Posted April 2 4 minutes ago, Duncan62 said: also put it under the shower tray Not sure they recommend that 1 Link to comment Share on other sites More sharing options...
Nic Posted April 2 Share Posted April 2 2 hours ago, Duncan62 said: Hello, Beginner at loopcad but like to try, put me straight. Wall/Roof/Floor all ~U=0.11. Windows ~U=0.8 UFH loops to be laid and fixed atop the mesh in the insulated slab before the pour. I've tried to keep to 3 x 100m loops which will all operate on a single zone. Low temp batch heated over night by the ASHP. Top-up on coldest days in the afternoon. GF area ~110 sqm Annual Heating Demand is 1800kWh/a (11.4 kWh/sqm a) Heating load for house is circa 1.5kw (PHPP). Option to cool UFH water in the summer via ASHP. Hi have got the dimensions of this area please , as I’m going to have quite a tight squeeze in my small utility room. Would be great to see how much space you’re set up is using and if you’re set on the DHW tank and MVHR units thanks Link to comment Share on other sites More sharing options...
SuperJohnG Posted April 2 Share Posted April 2 Make the loops tighter and more loops, you can always run at a lower temp and pipe is cheap. Link to comment Share on other sites More sharing options...
Mike Posted April 2 Share Posted April 2 1 hour ago, Duncan62 said: put it under the shower tray I would, and under the kitchen units too. 1 Link to comment Share on other sites More sharing options...
Dan F Posted April 2 Share Posted April 2 (edited) We used 200mm centres even though not strictly required given low heat-loss. 200mm is also slightly easier to install as you just follow the mesh, which is our case was also 200mm. We didn't go under any cupboards/island/stairs, can't remember why, I guess MBC advised not to, although in hindsight this is more important for UFH-in-screed than lower temperature UFH-in-slab. The main thing is to 100% avoid anywhere where they may be fixings into the slab. TBH, even if you don't you'll still be able to run at very low flow-temps, especually with 200mm centers. Edited April 2 by Dan F Link to comment Share on other sites More sharing options...
Duncan62 Posted April 3 Author Share Posted April 3 6 hours ago, Nic said: Hi have got the dimensions of this area please , as I’m going to have quite a tight squeeze in my small utility room. Would be great to see how much space you’re set up is using and if you’re set on the DHW tank and MVHR units thanks Hello, plant room is 1.9m x 3m 1 Link to comment Share on other sites More sharing options...
Duncan62 Posted April 3 Author Share Posted April 3 5 hours ago, Dan F said: We used 200mm centres even though not strictly required given low heat-loss. 200mm is also slightly easier to install as you just follow the mesh, which is our case was also 200mm. This is a good point that I had thought of last night too. Installing at 200mm will nicely follow the mesh spacing. Might make instillation easier. Link to comment Share on other sites More sharing options...
Jenki Posted April 3 Share Posted April 3 Never understood not putting pipe under units/ shower trays / baths, Especially if its a 100mm concrete slab. I just put loops over the whole floor, I didn't take into account any room layout. The slab was 120mm thick so I had 80 mm concrete to drill /screw fixings into if needed. Link to comment Share on other sites More sharing options...
Super_Paulie Posted April 3 Share Posted April 3 11 minutes ago, Jenki said: Never understood not putting pipe under units/ shower trays / baths, Especially if its a 100mm concrete slab. I just put loops over the whole floor, I didn't take into account any room layout. The slab was 120mm thick so I had 80 mm concrete to drill /screw fixings into if needed. i guess the theory is you dont want to warm up food in cupboards or dry out the traps under baths and showers? I avoided putting it under the units for those reasons and also that by doing so got me to give or take 100m instead of way over. Link to comment Share on other sites More sharing options...
Jenki Posted April 3 Share Posted April 3 50 minutes ago, Super_Paulie said: i guess the theory is you dont want to warm up food in cupboards or dry out the traps under baths and showers? I avoided putting it under the units for those reasons and also that by doing so got me to give or take 100m instead of way over. It's a solid slab, the heat will diffuse? through it, that's the whole point. To my mind your just making it work harder. Link to comment Share on other sites More sharing options...
Mike Posted April 3 Share Posted April 3 27 minutes ago, Jenki said: 1 hour ago, Super_Paulie said: i guess the theory is you dont want to warm up food in cupboards or dry out the traps under baths and showers? I avoided putting it under the units for those reasons and also that by doing so got me to give or take 100m instead of way over. It's a solid slab, the heat will diffuse? through it, that's the whole point. To my mind your just making it work harder. This. Link to comment Share on other sites More sharing options...
Nick Laslett Posted April 3 Share Posted April 3 (edited) @Duncan62 All looks good. You might want to try the serpentine counterflow pattern in LoopCAD. This places a flow pipe next to return pipe and evens out temperature. As others have pointed out, less than 200mm centres are more difficult on mesh. Make sure they follow your LoopCAD drawings. I have good drone shots of my install but only recently discovered that they installed less loops than specified. Two rooms in particular. Also ignored the routing of four loops through adjacent room to reduce the amount of pipes in hallway. This was the day before the pour, so hard to catch at the time. All my fault as I didn’t supervise after the initial discussion and had a late panic about lowering the French door thresholds and had to get some timber quick. Edited April 3 by Nick Laslett Link to comment Share on other sites More sharing options...
JohnMo Posted April 3 Share Posted April 3 16 minutes ago, Nick Laslett said: You might want to try the serpentine counterflow pattern in LoopCAD. This places a flow pipe next to return pipe and evens out temperature. Once you get to low outputs and flow temps below 30 or so you cannot notice. I didn't go under any kitchen fixed units, showers or baths, kitchen islands or beds. A Lot of the, "you better do this or that", only really applies to UFH installed in very high heat leakage houses and/or with little or no insulation below the pipes. Well insulated with heat output of 15W/m2 and below, you can do just about do any centres, any pattern, flow temp varies only by a couple of degrees. 1 1 Link to comment Share on other sites More sharing options...
Duncan62 Posted April 4 Author Share Posted April 4 Update. Thank all. I have avoided under shower and kitchen cupboards (some of them) simply because I have 3 x 100m loops, which works nicely for buying and fitting. I shall not do serpentine as it looks (much) more difficult for this mortal to install - and looking over @TerryE posts, will make no difference in low flow temp situations. Link to comment Share on other sites More sharing options...
JohnMo Posted April 4 Share Posted April 4 I would add an electric towel rail in to the bathroom as well. Other than that it looks good to me 1 Link to comment Share on other sites More sharing options...
Nick Laslett Posted April 4 Share Posted April 4 3 hours ago, JohnMo said: I would add an electric towel rail in to the bathroom as well. Other than that it looks good to me We did the same. You need something independent of the main central heating system so that you can easily dry towels and add some heat to the bathrooms in the shoulder months. 2 Link to comment Share on other sites More sharing options...
joe90 Posted April 4 Share Posted April 4 3 hours ago, JohnMo said: I would add an electric towel rail in to the bathroom as well. +1, nothing like a warm towel. 1 Link to comment Share on other sites More sharing options...
Duncan62 Posted April 4 Author Share Posted April 4 46 minutes ago, joe90 said: +1, nothing like a warm towel. 1 hour ago, Nick Laslett said: We did the same. You need something independent of the main central heating system so that you can easily dry towels and add some heat to the bathrooms in the shoulder months. Easy install after-the-fact if needed. I like it. Link to comment Share on other sites More sharing options...
TerryE Posted April 4 Share Posted April 4 Your UFH risers are coming very close to the side door. Make sure that you have enough clearance to get the manifold assembly in. 1 Link to comment Share on other sites More sharing options...
Duncan62 Posted April 4 Author Share Posted April 4 14 minutes ago, TerryE said: Your UFH risers are coming very close to the side door. Make sure that you have enough clearance to get the manifold assembly in. Thank you Terry: I plan to use the bottom side wall in the plant room which is 900mm wide. Enough for a 3x Out and 3x Return manifold + pump? Yours doesn't look too big? Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 4 Share Posted April 4 On 02/04/2024 at 21:49, JohnMo said: Not sure they recommend that In a "passive house" the flow temps are inconsequential. I now pipe under every single shower tray for my clients builds, staying around 400mm away from the waste / drain. Why? Not sure, but I am reasonably sure confident that it's entirely moot tbh. 1 Link to comment Share on other sites More sharing options...
Nickfromwales Posted April 4 Share Posted April 4 On 02/04/2024 at 22:45, Nic said: Hi have got the dimensions of this area please , as I’m going to have quite a tight squeeze in my small utility room. Would be great to see how much space you’re set up is using and if you’re set on the DHW tank and MVHR units thanks Go for a horizontal UVC and put everything else above it? Link to comment Share on other sites More sharing options...
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