Energy myth-busting: Is it cheaper to have heating on all day?

richardc1983

lstar337 wrote: »

My return temp is 50c keeping my boiler in condensing mode, yet it isn't on all day. The two are not entwined.

My boiler is currently on a timer for 2 hours a day, but I doubt it fires much as it doesn't take a lot to keep our house warm.

Sorry richardc1983, but even a building manager cannot beat the laws of thermodynamics.

THe lower your return the better, so yes your in condensing mode but with myself with a flow temp of sometimes 30c that gives a return of 25c, there comes a point where there is no plume outside as the boiler is recovering all that heat from the exhaust gases, this is super efficient.

As said its a difference of comfort for many and different house types etc. But for me having the heating on timed 6 hours a day at a comfort temp its better to have it 12 hours a day at a comfort temp then at night we set it back as we are in bed, but the boiler still comes on to maintain 18c when it needs to, albeit at a very low flow temp.

Bricks

The point that the boiler being in condensing mode is not entwined with it being on all day is the key one, isn't it? And it's perhaps this fact that causes much of the argument in these discussions.


But point taken (assuming it's correct) from @richardc1983 that there are different levels of efficiency within condensing mode and the lower the flow temp the better.


What works best will vary wildly between different buildings with different levels of insulation and thermal mass; the other thing that drives these arguments.


There may be buildings where all the necessary heating can be done using a very low flow temperature, *and* it's not necessary to have the heating on constantly.


For all buildings, there will be a big variation in the threshold for how long a period of inoccupancy means it's sensible to have the heating off. So some buildings, it will make sense to have the heating off during the day when people are out at work. Some buildings that will not make sense, but it would make sense to have it off if people are away for a weekend. Some where it only makes sense if you're away for more than a week, and so on.

Anthorn

thorganby wrote: »

It is pointless trying to educate Anthorn, whatever he says is fact based on his limited technical knowledge and his simplistic opinions nobody can tell him otherwise, so don't waste your time trying!

Is that a senseless and pointless personal attack or do you assume you know me and you have access to my energy account?

Personally, believe it or not, I know when I'm spending more money and I know when I'm spending less money. Ergo I know the when I leave my heating on more it costs more and when I turn off my heating it costs less. I know that because being somewhat older (68 years old) I feel the cold and there are times when my heating is on constantly such as when we had the beast from the east.

Alternatively perhaps we should tell those people who have to decide to either eat or heat to leave their heating on 24/7 because it's cheaper and they will be able to both eat and heat. At this point I go ROFL and close. ROFL.

richardc1983

Anthorn wrote: »

Is that a senseless and pointless personal attack or do you assume you know me and you have access to my energy account?

Personally, believe it or not, I know when I'm spending more money and I know when I'm spending less money. Ergo I know the when I leave my heating on more it costs more and when I turn off my heating it costs less. I know that because being somewhat older (68 years old) I feel the cold and there are times when my heating is on constantly such as when we had the beast from the east.

Alternatively perhaps we should tell those people who have to decide to either eat or heat to leave their heating on 24/7 because it's cheaper and they will be able to both eat and heat. At this point I go ROFL and close. ROFL.

But when you are talking of constantly you are suggesting you turn the thermostat up to compensate for the cold.

I don't adjust it above what its set at whether its 30c outside or -30c the boiler will adjust its output depending on those conditions.

My mum for example turns the thermostat up to 25C even though 22c would suffice, she then complains its too hot and turns it down to 10c and then would let the house cool down again before "feeling the cold!" and turning it back up to 25c rather than letting it sit at a reasonable temperature.

zeupater

Hi

Interesting discussion, but effectively irrelevant ....

Apart from some heat pump heating targeted at the main living areas, this year's mild start to winter has resulted in very little need for the main heat sources to be used so far - to date the GCH has been used twice, as has the log burner ... Opening up the internal doors last night resulted in temperature dropping in the main living area, but an increase elsewhere. The overall air temperature difference between last night (11pm) and now is approx 0.2C!

Now, our home leaks heat - it just does so more slowly than most others ... but that's the point isn't it! ... So, would we leave the heating on? - well, even though the thermostat wouldn't call for heat very often, certainly not às it doesn't make sense. We have days where there's a heat defecit & there are others where solar gain plus living area heating provide a surplus so they often balance out over a couple of days and as there's not many people they can differentiate temperatures to a tolerance of <1C what's the point of spending more money than necessary?

The main use of our GCH is to top-up the DHW at this time of year when the solar thermal struggles to cope on it's own, but that's only once or twice a week ... the entire house is drawing 460W at the moment, all of that being supplied by solar panels , so somewhere around 2kW of heating for free ... it's just under 20C where I'm sitting & warming slowly despite it being 7C outside ... with today's solar gain I'd be confident in predicting that the entire house (on average) will be warmer tomorrow than today, thus helping charge the thermal mass with heat to help later on when we have a few cooler days ..

The real answer lies in being sensible as to where & when heat is required and when it's needed as well as the level of planning & measures to keep it in after it's been delivered ... obviously we've done it - I'm just surprised that the argument regarding heating periods still persists - it must be a seasonal thing ... Oh no it isn't - Oh yes it is ... what's forgotten is that whenever the boiler fires up after a period of time it will be working to heat the circuit up & therefore whether this happens once/day on short burst heating or multiple times on a long term basis, it still happens .... where there's heat loss, that heat needs to be replaced with the certainty that the greater the ambient differential, the greater the rate of loss ... in almost every case the answer is clearly to provide heat when comfort is required, not to waste money & resources!

To those who have been running single day tests the question revolves around ambient conditions, accuracy & residual energy in the form of thermal mass ... it logically shouldn't be ignored so far more robustness would be required in the test methodology!


HTH
Z

thorganby

Anthorn wrote: »

Is that a senseless and pointless personal attack or do you assume you know me and you have access to my energy account?

Personally, believe it or not, I know when I'm spending more money and I know when I'm spending less money. Ergo I know the when I leave my heating on more it costs more and when I turn off my heating it costs less. I know that because being somewhat older (68 years old) I feel the cold and there are times when my heating is on constantly such as when we had the beast from the east.

Alternatively perhaps we should tell those people who have to decide to either eat or heat to leave their heating on 24/7 because it's cheaper and they will be able to both eat and heat. At this point I go ROFL and close. ROFL.

That is the point, I do not make assumptions and wild generalisations like you constantly do!

I have proven myself that in my house, using a programmable thermostat with set back temps that prevents the house becoming too cold saves me money but you will not accept my or other peoples findings.

The thought of a 68 year old pensioner rolling on the floor laughing at this is quite amusing to those of us who have proved you wrong.

Anthorn

thorganby wrote: »

That is the point, I do not make assumptions and wild generalisations like you constantly do!

I have proven myself that in my house, using a programmable thermostat with set back temps that prevents the house becoming too cold saves me money but you will not accept my or other peoples findings.

The thought of a 68 year old pensioner rolling on the floor laughing at this is quite amusing to those of us who have proved you wrong.

ROFL: There you go.

There is another branch of the discussion. In a nutshell, the more we heat our homes the greater the difference between the indoor temperature and the outside temperature and therefore the greater the heat loss and in turn the greater the amount of energy wasted and therefore the greater the amount of money wasted. Insulation is a factor but as far as I know no insulation prevents 100% of heat loss, not even my triple glazing.

How do you know I'm a pensioner?

lstar337

zeupater wrote: »

Hi

Interesting discussion, but effectively irrelevant ....

Apart from some heat pump heating targeted at the main living areas, this year's mild start to winter has resulted in very little need for the main heat sources to be used so far - to date the GCH has been used twice, as has the log burner ... Opening up the internal doors last night resulted in temperature dropping in the main living area, but an increase elsewhere. The overall air temperature difference between last night (11pm) and now is approx 0.2C!

Now, our home leaks heat - it just does so more slowly than most others ... but that's the point isn't it! ... So, would we leave the heating on? - well, even though the thermostat wouldn't call for heat very often, certainly not às it doesn't make sense. We have days where there's a heat defecit & there are others where solar gain plus living area heating provide a surplus so they often balance out over a couple of days and as there's not many people they can differentiate temperatures to a tolerance of <1C what's the point of spending more money than necessary?

The main use of our GCH is to top-up the DHW at this time of year when the solar thermal struggles to cope on it's own, but that's only once or twice a week ... the entire house is drawing 460W at the moment, all of that being supplied by solar panels , so somewhere around 2kW of heating for free ... it's just under 20C where I'm sitting & warming slowly despite it being 7C outside ... with today's solar gain I'd be confident in predicting that the entire house (on average) will be warmer tomorrow than today, thus helping charge the thermal mass with heat to help later on when we have a few cooler days ..

The real answer lies in being sensible as to where & when heat is required and when it's needed as well as the level of planning & measures to keep it in after it's been delivered ... obviously we've done it - I'm just surprised that the argument regarding heating periods still persists - it must be a seasonal thing ... Oh no it isn't - Oh yes it is ... what's forgotten is that whenever the boiler fires up after a period of time it will be working to heat the circuit up & therefore whether this happens once/day on short burst heating or multiple times on a long term basis, it still happens .... where there's heat loss, that heat needs to be replaced with the certainty that the greater the ambient differential, the greater the rate of loss ... in almost every case the answer is clearly to provide heat when comfort is required, not to waste money & resources!

To those who have been running single day tests the question revolves around ambient conditions, accuracy & residual energy in the form of thermal mass ... it logically shouldn't be ignored so far more robustness would be required in the test methodology!


HTH
Z

Nice to see sense return to this discussion.

lstar337

richardc1983 wrote: »

You are so clearly uneducated on this subject...

:rotfl::rotfl::rotfl::rotfl::rotfl:

richardc1983 wrote: »

You talk as if we have the heating left on blasting at 30c all year round... no its set at 21C for example, if it drops below that in summer then yes the heating comes on but the flow temp will be at the minimum sometimes 25C to bring it upto that using minimal gas, the temp is always kept to within 0.1c of set point.

If you left your house empty for 3 months, would you leave the heating on?

If yes, for what benefit?

richardc1983

lstar337 wrote: »

:rotfl::rotfl::rotfl::rotfl::rotfl:

If you left your house empty for 3 months, would you leave the heating on?

If yes, for what benefit?

It would be left at say 16c to stop any damp etc coming into the house.

If you came home after 3 months it may possibly take 48 hours or longer before the building fabric comes upto temperature and the heating would be working mad, but if you are not going to be there for 3 months then why would you have the heating on of course you are going to save money. Of course it will use a lot of gas to bring it back up to temperature but not as much as if we left it at a comfort temperature for 3 months. This is the key it is comfort.

There is of course a point where it is more efficient to have the heating turned off but for us presently we are talking of say 12 hours timed vs 24 hours constant (with setback) and it all depends on insulation levels of the house.


Its ok arguing but you are not taking any points on board of people who this is working for, are you calling those liars?

We are talking of day to day heating of timed vs constant with night set back temperature. Do you also realise underfloor heating is to be left on constant because it uses a lower flow temperature to keep the house at a constant temperature, this in turns saves money as the system is just ticking away.

Until you understand the technology out there today there is no point going any further with you.