marshian

Would have expected a water requirement would be based on occupancy not bed rooms - our 4 Bed house has had a 115 litre tank from new But it’s BUS grant and MCS so probably all a bit crazy from an energy efficiency you only ever want to heat the water that’s needed??

180 Litre tank?? how many showers are required? (See note) Just two of us in the house 115 litre tank we heat to target 50 deg C in the morning with a flow temp of 60 deg (takes 40 mins on average from it’s mid 30’s start point the tank is old style copper with foam casing and not a very big coil so loses ~0.5 deg per hour (was much higher losses before a london loop was added) this means we can still wash up and comfortably have a further two showers in the evening before the tank is fully depleted. I could probably heat to a slightly lower temp maybe 47 or 48 but my old school tank stat has 50 deg as min - below that is off!!!! (I really should buy one that allows a lower set point) Note - If Teenagers are involved all bets on water usage are off

with 8-9 cm of build up to play with you can’t put the required level of insulation down. so don’t put any down did you watch the Urban Plumbers you tube I posted it explains why

Don’t bother at all

Not actually true - @JohnMo’s advice if doing UFH was to either fully insulate or do no insulation at all. If you continued with you current floor insulation levels you’d be better of using rads I occasionally disagree with @JohnMo but on this issue I completely agree with his viewpoint I kinda agree with him with regard to you have already made up your mind and are going to do it anyway so it’s kinda pointless to comment any more. Heat loss calcs - design UFH to meet the heat loss at whatever min winter OAT is typical of where you live - set the boiler up with WC and DHWP and don’t complicate the system with buffers, mixers and thermostats because that will increase both the capital costs and the running costs

The room by room heat loss calc will help you to understand the heat loss of each room and that means you can get the pipe spacing right for the needs of each room Just using 100mm spacing everywhere doesn't make sense to me - if a room has a low heat loss then you are going to have to restrict the flow thro that section to achieve the target room temp - now that may well be fine for the odd room but your boiler is going to need a level of flow to be happy - why put excess pipe under a floor for a room that doesn't need it and then shrink the circuit flow to compensate? I've got an 80's house - yes it now has blown CWI, SUDG windows and doors, 325 mm of Loft insulation and 75mm of PIR under the suspended ground floor as improvements over the original build spec but the heat requirements of each room can be very different (due to number of external walls in some rooms, patio doors in living areas) as a result the rad sizes are very different and where they are similar the flow rates aren't I'm using a gas boiler not ASHP but I do heat 24/7 from Sept to May I've sized my rads to meet the heat loss needs with flow temps linked to weather compensation (34 Deg C at -2.5 DegC OAT) with the flow rates controlled so I can heat 24/7 maintain a stable comfortable house temperature with a boiler that is happy because the circuit never shrinks) This is the most comfortable the house has ever been - certainly massive improvement compared to higher temperature scheduled heating Trial an error whilst it works, takes time and is no substitute for a good system design right from the start

Anyway individual bathroom temp discussions are taking this slightly off topic. I'm hoping @mikeysoft has a little more insight into the subject and how looking at the whole house heating needs requires both a room by room analysis paying careful attention to the flow temp and heat input (either rad sizing or UFH spacing and pipe size)

As does ours and that is fine for daily showers in the winter - it shares a wall with bed 1 which is heated to 20 Deg (Mrs Alien is not someone who copes well with a bedroom at only 18 deg C - compromises in life we all have to make them 😉 ) Bathroom and En-suite are identical from the perspective of 1. dimension (L x W x H) 2. Insulation above the ceiling 3. Insulation in the brick cavity 4. Radiators are also identical as is the flow rates & temp thro them However the bathroom needs to be a lot warmer than 20 Deg C when she wants a bath and this was a source of some discussion (hence considering the rad upsize until I realised that it can be achieved by heating the adjacent room with a less aggressive setback

Large box of latex/nitrile gloves - any on the gloves and it's glove change time.

^ spot on @SimonD I have a good example of exactly this to throw into the mix My house is T shaped, one edge of the T is north facing and has front hall and bed 4 (PC room/study) above both have 3 external walls - heat loss from these areas is quite high and they are infrequently used so it's they are the only rooms/areas where I run heating to a scheduled heating and at a much lower target temp (Typically 16 deg C). Next to bed 4 is the bathroom - it's radiator should be capable of getting the room to 23 deg C but it struggles to get above 20 and I was getting to the point in Nov last year where I was going to up size it - right until the xmas break when I spent a bit of time in the study doing an annual paper shredding exercise and had reverted the schedule to 24/7 because running low flow temps the warm up time can be a day or two to react to a change Bathroom temp went up by 1.0 to 1.5 deg in this period................ A really good example of the radiator in a warm room losing the battle because it's having it's input to the room being leached out to heat the colder room next door. I've now increased my loft insulation from 75 mm to 325 mm to reduce my ceiling losses in the whole house and my winter plan is to run a far less aggressive set back temp in bed 4 - possibly even go 24/7 with a smaller differential. There was another good video from Urban Plumbers recently where he was doing an install and the existing rads in the bedrooms were on the edge (output wise) at the design flow temps - all the bedrooms were off a shared landing and the action to resolve was not replace/upsize all the bedroom rads but add a rad to the landing to reduce the differential between the areas. The more I think about what UP's did the more I realise that my bathroom shares 1 wall with Bed 4, 1 wall with the landing (only heated from 1 rad downstairs) and 1 wall with the stairwell so the hot has plenty of cooler areas to go

Lovely post @SimonD @mikeysoft "Experience is what you get when you don't want it" My house built in the early 80's had T11 rads throughout - they were originally fed by a high temp non condensing boiler and I'd changed that to a condensing boiler and got a little energy saving Over the years single glazing got swapped out for double glazing - 25mm of loft insulation got upgraded to 75mm - empty cavity wall got insulation blown in - all giving small but incremental improvements in energy consumption A few years ago I "upsized" some of the rads in my house (mostly bedrooms, living room and hallway) from original single panel, single convector rads to double panel double convector rads - my assumption was I could run lower flow temps improve boiler efficiency and reduce my gas usage It was to be frank a bloody disaster Rooms with upsized rads heated up far faster than ones with the original rads, the TRV's closed to limit the room temp This meant that the heating circuit was half the total volume once the TRV's shut down - the boiler then cycled like crazy wasting loads of gas and my energy costs went up not down Lower flow temps meant that the rooms with original rads didn't heat up as quickly but now with a circuit volume that had shrunk and a boiler that cycled like crazy they never came up to temp unless I increased the flow temp Increasing the flow temp meant that any condensing eff gains was lost and I learnt a valuable lesson I upgraded the remaining rads and was then able to run lower flow temps for the whole house - downside was my boiler wasn't capable of running the lower flow temps to not overheat the house 45 deg C was as low as it could go with sensible burn times I did a room by room heat loss calcs - swapped some rads about and replaced a couple of rads where the move from T11 to T22 wasn't balanced to the heat loss and ended up with a house that could be heated with 30 deg flow temp even at zero outside Except my gas boiler would short cycle when set to anything below 45 So I changed the boiler for one that could run low flow temps and now I can heat 24/7 low and slow and get the benefits of boiler efficiency It doesn't matter if you use Rads or UFH you really need to have a very good idea of heat loss and align flow temps with the size of the rads or spacing of the UFH pipes to meet the needs of the room Oh and micro managing room temps to save energy doesn't work either - there is a great heat geek video on that "Stop turning off radiators in unused rooms" it covers the reasons why it can actually cost you more So in summary people on here are trying to stop you making the same mistakes we've already made

Two ways to do do UFH - With a lot of insulation under the floor or with none Skip to 11:30 to the bit that covers UFH in an un-insulated slab @JohnMo is pointing out you are in "no mans land" where a little insulation can actually be worse than none

You don't - You can have different temps in different areas of the house by controlling the flow rates (you can do this with flow rate supplying each loop) what you don't want to do is control temps with thermostats/actuators @JohnMo is stressing the importance of having a nice open system with no thermostat/actuator controlled zoning which is bad for efficiency (boiler cycling) I have 13 rads - only two have set backs using "Smart" TRV's - rest all are controlled by matching flow rate to heat loss to achieve the desired room temp means system volume is ~100 Litres so plenty of water to keep the boiler happy

to expand on ^ if your boiler can run low flow temps for CH and flip to higher temps for HW (ie with Weather Compensation and DHWP) then running at fixed flow temps with mixers and additional pumps for UFH make no sense my max flow temp for CH at -2.5 outside is 34 deg C (weather compensated system) return temp is in mid to high 20’s so condensing all the time with a boiler efficiency of 97.5 % (validated because I found out how to calculate it) my max HW reheat temp is 80 deg C - efficiency is probably not much more than 86 % - I don’t care because I run the CH 24/7 on low flow temps at max eff and only heat HW tank for 20 - 30 mins a day. So the efficiency gains on CH cover off the poor eff on HW

So are advantages of split units using refrigerant things like no glycol/antifreeze valves, no defrosts and a higher flow temp is possible than A2W Heat pumps? The COP from memory was high 3’s in middle of winter and high 4’s to low 5’s in shoulder seasons House is a fair size (so will cost to heat) but to me the energy bills over winter are eye watering it was built 6 years ago to regs UFH throughout with additional big towel rails in all the bathrooms what concerned me from an efficiency perspective was the buffer, number of pumps in the system and thermostats in every room

I wasn’t questioning the modulation 😉 The boiler will have a min flow temp that it can work at - that temp may well be higher than a UFH system can cope with my old Glow Worm boiler stated min flow temp was 39 deg C - it wouldn’t run at that temp - lowest practical operating temp was 45 current boiler min flow temp is 20 deg - lowest practical operating temp is 25 deg should be documented in the installation manual

I think it must be

I don't think @mikeysoft's WB LPG Boiler is capable of the low flow temps for UFH - and probably not able to do DHWP either

Data is always good - I'm seeing an improvement in both internal humidity levels as well as loft humidity levels Changes have been driven by Improvements to loft insulation (from 75mm to 300 mm) and ventilation (eaves trays and gable end vents) (Loft temps are rising, humidity levels are falling) Changing the speed of the PIV unit for the shoulder and summer months (Increased Air changes and air supplied from the loft is drier) I was tempted to move my internal temp and humidity monitor as it's in a relatively cold room compared to the rest of the house but because it's always been there I'm reluctant to have a change in data. Add to that the insulation levels above the room have been improved I'm hoping I can heat 24/7 without setbacks

I'm guessing it's high temp split with refrigerant I only noticed the pipe size because the insulation is also quite small and is in a poor state in places - guess that might be impacting efficiency?

Went to my friends house this weekend - fairly large bungalow with a ASHP set up Looked at the heat pump and was really surprised to see the primary pipes are tiny (like microbore size) I was expecting 28mm pipework from the ASHP to inside

I am right in thinking that ring circuits is very much a UK thing and stems from "economy" post war - less wire used and lower grade of cabling required? In Europe they are radial??

Just to add Setting 2 has been my winter setting but Setting 4 has become my go to setting for spring summer and autumn Reason is adding insulation to my loft has resulted in an increase in loft temps - the PIV cuts out if loft temps get over 27 deg C So it's running half the time it would during winter so I've increased the flow rate and it seems to work nicely - especially at night when the loft temp rapidly falls and it's helping to cool the bedrooms during the night. The silver fan of doom hasn't been deployed yet this year (Mrs Alien doesn't like it hot in a bedroom in the summer so despite the fact she's a light sleeper the fan gets deployed and as it's a constant noise she copes with it - I can't stand the noise it makes although I can sleep thro a hurricane I can't get to sleep in one so dislike the fan being deployed) In spring / autumn during the day it does a reasonable job in transferring warm loft air to a cooler house

Christ!!! That's quite a number. /joke - But then again if I'd applied to build a dungeon under my house I'd have probably got a few more oblections Having said that with the water table as it is it would be a below ground swimming pool 90% of the year and a little drip would be the last of my concerns 😉 How many of the neighbours still don't talk to you?

I had three objections to a two storey extension to the house and a single storey extension to the attached garage (all in one application) All were from an immediate neighbour. 1. Over development of the land (from neighbour with less garden than I would have post extension) which made me chuckle. House extension was replacing the footprint of an aluminium single glazed conservatory and garage extension was replacing a wooden shed. 2. Concerned about the possibility of running a business from the garage (I like cars I have a few and I do all my own maintenance / restoration - not got time to do work on other cars) 3. Proposed new window for en-suite would overlook neighbours bathroom window (their window was frosted glass - proposed new window was specified as frosted glass) Planning was granted