Obsessing about heating again

newbiejim

newbiejim

newbiejim

Soldato
Joined
22 Jun 2004
Posts
2,693
Location
South Scotland
Yesterday as a sort of experiment I turned my heating flow temp down to 60 degrees C and left it on all day to heat house to 20.5.

  • 1950s 3 bed largish semi, part coombed ceilings upstairs, loft insulation no cavity insulation, so not overly insulated.
  • Boiler: Vaillant Ecotec Plus 831
  • Flow temp: 60c
  • Outside temp: 5c
  • Rads: 8, 3 large, 4 medium, one towel rail.
  • Time On: 8am
  • Time Off: midnight
  • Gas used: approx 350 cubic feet
  • Approx cost: £5

IMHO that's isn't TOO bad, I`m def going to try lowering flow temp more with long slow burn times etc.
Anyone else have any idea how much their heating costs per day etc to heat to similar time/degree?
edit:it did take about 4 hours to get up to temp.
 
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Got a couple of 150mm width self adhesive foil rolls off a skip a while back.
Finally got around to using it yesterday by putting the foil behind the radiators which are located on a outside wall.

Can't even see it, as it's just slightly smaller than the radiator, will paint later.

Once i've replaced radiator in front room, I going to take the time & balance the heating system, as I have a couple of very hot radiators, & one is only warm.
 
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I have been running my flow temp at 45c for about 5 or six weeks - the idea being that the radiators take as much heat as possible out of the water so the return temperature is as low as possible - this makes the boiler more efficient as it uses its condensing process to better effect. I would suggest that you should turn your flow down to at least 50c to see how that goes.
 
What's the deal with stored hot water minimum temperatures? Isn't there a point that you reach where it's not hot enough to kill germs and you just end up with a bacteria breeding ground?
 
budwozza said:
I have been running my flow temp at 45c for about 5 or six weeks - the idea being that the radiators take as much heat as possible out of the water so the return temperature is as low as possible - this makes the boiler more efficient as it uses its condensing process to better effect. I would suggest that you should turn your flow down to at least 50c to see how that goes.
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Yes that's why I`m doing this, so the boiler condenses most of the time and is more efficient, have you any idea how much it is costing you to do this?, obv there are many variables but might give us insight into sweet spot for performance/cost.
 
Trifid said:
In a day? That can't be right. Or do you mean Kwh? But your cost would be around £15 (which is a lot!)
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I may be misunderstanding the units, my meter is in cubic feet and I just assume it was hundreds?, lol we need someone to clear this up.

Anyways, post British gas price rises for 5 of these 'units' cost £7.14 which is 160.37 kwh x 4.450p, this is from my bill.
 
newbiejim said:
Yes that's why I`m doing this, so the boiler condenses most of the time and is more efficient, have you any idea how much it is costing you to do this?, obv there are many variables but might give us insight into sweet spot for performance/cost.
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No idea yet as we take readings monthly, also our shower / hot water is heated from the boiler and as it's Christmas we have used more.
 
I am heating a new build property with floor space about that of a 2 bedroom flat. I tend to keep the room thermostat controls on manual, and switch them up/down depending upon what I am doing. I have two thermostat controls. One that controls the kitchen/living room, and the second one controls the hallway/bedrooms.

If I am not using a specific area of the property I tend to switch that one down to 13/14 degrees. Overnight I keep the one that controls my room temp to about 15 degrees so I don't wake up freezing cold. I can work some odd hours so setting my heating to come on/off via a timer is tricky.

My thinking is that by having the heating on more often but at lower temps I can keep the house from feeling too cold, or too hot, and ultimately doesn't seem to really cost me any extra.

I have been using approx 25 units a day (gas KwH) according to the Scottish Power meter readings I take for them. The Gas KwH figure is taken by the meter reading * 11 approx, so I am using a little over 2 gas units a day on the meter (it's the new one, metric I think instead of imperial).

For power I am using a pretty consistent 6 KwH units a day.

My combined bill at the moment is approx £60/Month for both gas/electric. £15 of that is standing charges instead of actual usage though with about a 50/50 power/gas usage ratio. During the summer I was spending around £35-£40 a month on both bills as gas had very little usage.
 
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Caged said:
What's the deal with stored hot water minimum temperatures? Isn't there a point that you reach where it's not hot enough to kill germs and you just end up with a bacteria breeding ground?
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To kill legionella your tank needs to be at least 60c. Not sure about any other bugs. I turned mine down from 85c to 65c after finding that out. However that's not what these guys are talking about.
 
PistolPete said:
To kill legionella your tank needs to be at least 60c. Not sure about any other bugs. I turned mine down from 85c to 65c after finding that out. However that's not what these guys are talking about.
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If you have a combi boiler with no hot water storage facility, then the perceived risk from legionella is low.
You only get legionella in hot water cylinders and cold water cisterns,etc & not in a sealed central heating system.
Legionella needs a ideal water temperature between 20–45 °C (68-113F) to thrive,below 20°C it can be present in water, but is dormant.
 
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I wouldnt be turning flow temps down to 50 - 60degrees in order to try and save gas lol

at those flow temps your rooms will take forever to heat up.

Put the boiler stat on max to get the rads red hot then your house will heat up faster and then the boiler can be on less time :rolleyes:
 
The_One said:
I wouldnt be turning flow temps down to 50 - 60degrees in order to try and save gas lol

at those flow temps your rooms will take forever to heat up.

Put the boiler stat on max to get the rads red hot then your house will heat up faster and then the boiler can be on less time :rolleyes:
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Yes that's the conundrum, IS that the best way?, u can have ure boiler on for ages at low temp, so pretty much on all the time.....maybe...........its very difficult to get solid information on this, probably because there are so many variables.

It took my house about 4 hours to get up to temp with 60c flow temp.
 
newbiejim said:
Yes that's the conundrum, IS that the best way?, u can have ure boiler on for ages at low temp, so pretty much on all the time.....maybe...........its very difficult to get solid information on this, probably because there are so many variables.

It took my house about 4 hours to get up to temp with 60c flow temp.
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4 Hours to reach the desired temp? How cold was it to start with and what temp did you try to achieve.

I would suggest that something is not right with your system.
 
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The_One said:
I wouldnt be turning flow temps down to 50 - 60degrees in order to try and save gas lol

at those flow temps your rooms will take forever to heat up.

Put the boiler stat on max to get the rads red hot then your house will heat up faster and then the boiler can be on less time :rolleyes:
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Suggesting that you set you flow to max is a bit of an irresponsible statement, my boiler can be set at 75c, hot enough to hurt children or OAPs if they were to touch the radiators.

Do you have any data to back this up?

The_One said:
modern condensing boilers are modulating anyway, they will modulate when the return temp is getting near its target
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I have set my temp flow temp to 45c, my room stat is set at 19c, the house drops to around 14/15c during the night when the heating is off. In the morning when the heating starts, it takes around 30 mins or less to reach 19c.

Everything I have read so far suggests that the greater the difference between your flow temp and return temp the more efficient the boiler performs, and the best way to achieve that is to have your flow as low as you can.
 
budwozza said:
Everything I have read so far suggests that the greater the difference between your flow temp and return temp the more efficient the boiler performs, and the best way to achieve that is to have your flow as low as you can.
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Correct, but you need to balance the radiators first, so you haven't got one very hot (usually closest to boiler) & another slightly cooler, they all need to be near enough a uniform temperature.

Then you can look at reducing your flow & return temp.

Have read of this link.

http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=8266
 
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