marshian

I'm just saying start low (ish) and work your way up if the house remains cold - I have this irrational fear that you will start high, pronounce the house too hot, can't sleep and turn it off again People tolerances are different - I'm "hot" above 19 - Mrs Alien - different kettle of fish less than 21 is freezing!!!! Well we can start there - what size and type are the rads and what sizes are the rooms - we have enough knowledge on here to start piecing it all together and come up with a reasonable punt I have a gas boiler and I'm running it like an ASHP - CH 24/7 low flow temps (between 25 and 35 Deg C based on weather comp) - when doing HW it raises the flow temp to heat the tank. I could replace it with a 5kW HP tomorrow and know it would work perfectly - this was the point of my rad upgrades and insulation improvements - get HP ready without leaping into it and then finding all my calcs were wrong and I've got a problem.

No point saving money with a lower flow temp if the house remains freezing 😉 We don't want @zoothorn cooking though do we 😉 I'd start in the middle (35 Deg) and see where the house settles - increase or decrease accordingly

What Flow temp you need is simple - the lowest flow temp required to heat the house with the rads you have My house with a gas boiler is between 25 and 35 depending on outside temp............ But I did fit big rads so that I could do low flow temps

My neighbour had a bloody great conifer in his front garden - far to big for the space - completely blocked the light to his front room. He never pruned it or even topped it. I asked him several times to trim it but he refused. It also meant my side gate and his side gate weren't visible from the road and a low lifer decided he'd gain access to my back garden and break in thro the French doors. As a result I pointed out to him that his house would probably be next and he'd probably need to get a better back gate. shortly after he had it removed but not before the cheeky bugger asked me if I'd go halves on the cost

Absolutely - flow temp and the size of the rad are fundamental to the heating ability of a radiator Example T22 800 x 600 (so this is a double panel double convector rad that is 800 long and 600 high) Supplied with a flow temp that results in a mean rad temp of 50 Deg output is 1.205 kW Supplied with a flow temp that results in a mean rad temp of 30 Deg output is 0.366 kW So a 20 deg drop in mean rad temp results in a reduction of 70% in heating output

The pandemic resulted in a lot of people (who were located close to London office for an easy short commute) suddenly found they were WFH in pokey accomodation where they only normally just slept, so they upped and moved further out because if you've got to WFH you can work anywhere.

You can have both when it's not dragging round 2,000 plus kgs I was fixing headlights so bumper had to come off

That looks much better

Nice Boomtown Rat Reference

Because he's been told it cannot work by an "expert" - therefore it cannot work - doesn't matter what anyone else says because "not experts" It's not suitable for anything other than heating water and that's the end of it.............

Do you sleep in 3 different bedrooms? Do you spend time in the kitchen and sitting room overnight too? That's what you are doing now - how is that working out for you?? I just checked not a full moon till 3rd March. HTH

It’s meant well if you are lost on the roads sat nav will get you home - but if you ignore it and decide you know better you can end up lost. the contributions here regarding zoots ASHP are well meaning so think of it as sat nav directions…,.. zoot can chose to ignore it……

It means literally - want a warm house in the day you need to allow it to trickle heat in 24/7 Want a cold bedroom - turn the bloody rad off overnight and back on in the morning

Sat nav works for roads....... ASHP not so much

Exactly........................................

If you are using low heat levels to cover the heat being lost - you run the heating 24/7 - you can add a little setback if you want to bedrooms at night or fit trvs and cap the bedroom temps that way but the issue with setbacks is you need to run a higher temp to recover from the setback period My house bedrooms are at 18, living areas 20 and bathrooms 21 - all other areas are between 16 and 19 house is far more comfortable than heating am and PM in timed slots and the cost difference for me is an extra £60 a year - I’m happy to pay that because I can do that on a good night on the beer!!!!

I can go along with that I didn't want to go down the route of explaining what ON means for my house but since you've pulled me up on the word ON Outside temp sensor tells the boiler how cold it is - based on this temp the weather compensation curve sets the flow temp At outside temps below minus 2.5 the boiler pretty much consumes energy all the time at a rate of 4 kWh (so peak consumption when it's that temp outside in a day is 96 kWh (plus a 4 to 5 kWh for HW) This means my peak cost is £5 a day (100 * £0.05) When it's not bloody cold the boiler cycles - puts in some heat "on a burn" - circuit cools down "on a coast" Depending on the outside temp the burn can be as little as 20 mins or as much as 60 mins and the coast can be as little as 10 mins or as long as 3 hours - All I am trying to do is replace the heat lost and that heat lost is directly related to the difference between warm inside house and colder outside house - I'm not trying to heat the house....... It is a comfortable temp all the time because the boiler is putting back what the house is losing PS I have no TRV intervention - they are there as absolute room temp limiters in the event of solar gain Each rad is sized to the room heat loss No UFH (all rads) Flow temps range from 25 deg to 33 deg C - no rad ever feels warm!!!

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Don't drag me into this madness @-rick- To the OP My heating goes on in Sept and it get turned off in May once it is on it's on 24/7 - no setbacks at night - no comfort setting in the day time or any time - it's just on on permanently on - never turned off it's just ON ON Why? because as soon as the outside air temp drops below an average of 16.5 deg C this house needs a heat input (it might not need a lot at the start but it needs some so it gets some) - if I let it cool down in the winter it can take several days to get back to temperature and I'll pretty much consume the same amount of energy as if I'd left the heating on all the time so I don't because it's pointless. You are trying to heat a house with short bursts of heat from a heating system that is better suited to long low and slow - sorry but that's frankly madness................. I'm out.

I'm trying to help a friend with mental health issues - he's been living on his own in a house with no heating working over winter (I wasn't aware of this till I visited) - surprising how quickly he's gone downhill - it's a 25 year old house but no real fire or wood burner to revert to like an older property. when I visited it was actually warmer outside than inside. I'm not actually sure what is wrong with it but I'm going to try to get it fixed (providing the gas hasn't been cut off which is always a possibility!!)

I'm out - Late Shift

That's what I would be doing - a thin layer of foil insulation isn't going to have much impact on heat loss on a suspended ground floor

Really depends on cyl size and how much has been depleted - I was taking worst case scenario in a house with 5 people I have 117 Litre Cyl (2 people) 4 showers a day (two morning and two evening sees the top of the tank at 38 and the bottom at 12 - I can guarantee you that the average cyl temperature is not 26 Deg C (best guess would be 10 L at 38 and 107 litres at 12 would be an avg temp if you mixed it of 16 Deg) @Bigdeadbadger would be in more HW trouble if his three kids were girls

Mine gets that low every damn day.............. Cold water in is less than 12 Deg C right now

If my mental maths is right I'd say your water heating is going to need more poke than your space heating so get a boiler which will go as low as possible for space heating (Viessmann 200 will go down to 2kWh) Then size the boiler to to recharge a 400 litre cylinder with a heat pump coil in the shortest time possible (so 400 litres from 20 to 55 needs 17 kWh of energy) to do that in ~30 mins would need a boiler capable of throwing 32 kW at it)