Is room taking too long to warm up?

[endecotp]

Threads like this are great because they help you work out who is worth listening to and who can safely be ignored.

 

[bhm1712]

I keep my heating on 24/7 and controlled to 20.0 degrees. This way, my system only ever needs to raise the temperature by a maximum of 1 degrees. (1 degree differential on the room stat) This way, my boiler spends about 3 hours within a 24 hour period on, and the rest off.

My gas bills are low as opposed to people's who have the heating on for a couple of hours in the morning and 5 or 6 hours in the evening bringing the house back up to an acceptable temperature again.

Let's assume that you are being truthful about the burn time of your boiler. (Which is very very unlikley)

In your example your boiler only burns for 8 minutes every hour to maintain a constant 20C +/- 1 totaling 3 hours in a 24 hour period.

If the OP was to set timer to ON 06:30/OFF 08:30 allowing a constant 30 minute warm up period and the 12 minutes ignition for the other 1 1/2 hours that's a total of 42 minutes of the boiler running.

Back on at 16:00 and off again at 22:00 again allowing a 30 minute warm up period and 44 minutes for the other 5 1/2 hours that's a total of 74 minutes

Total boiler ignition time in a 24 hour period is 116 minutes or 1 hour 56 minutes so a whole hour and 4 minutes less then your way saving a 1/3 on the energy usage.

All the above assumes a fixed Kw being used by the boiler.

Now add into the equation these supposed expensive pointless controls that will incorporate weather comp and open therm technology that will modulate the burner while running to adjust flow temperature and adjust the warm up period to take into account for ambient temperatures that saving will only increase further probably in the region of an additional 5 - 10%

All the above is obviously only a paperwork exercise and there are too many variables but you can see how wrong you are with your assumption that running 24/7 is a better way of doing it.

@garmcqui If you could get a 400mm x 1600mm in there that would push you up to about 2.1Kw

Jon

...but it isn't working...because his room isn't achieving the temperature he requires in the set time period....

 

[hazetimesfive]

Say I have two leaky buckets.

I give one to bhm1712. He keeps it always full to the brim, with constant topping-up.
I give another to garmcqui. He fills it to the top, waits for it to empty, then fills it again.

Who uses the most water in the long term?

worst analogy ever.

 

[bhm1712]

...the boiler never has to input as much heat into the house to maintain the temperature at a constant and it doesn't require excessive warmup periods.

 

[hazetimesfive]

I would also estimate that if you have an intelligent thermostat, it would be more efficient with constant heating.

 

[Aquaheat]

I keep my heating on 24/7 and controlled to 20.0 degrees. This way, my system only ever needs to raise the temperature by a maximum of 1 degrees. (1 degree differential on the room stat) This way, my boiler spends about 3 hours within a 24 hour period on, and the rest off.

My gas bills are low as opposed to people's who have the heating on for a couple of hours in the morning and 5 or 6 hours in the evening bringing the house back up to an acceptable temperature again.

Let's assume that you are being truthful about the burn time of your boiler. (Which is very very unlikley)

In your example your boiler only burns for 8 minutes every hour to maintain a constant 20C +/- 1 totaling 3 hours in a 24 hour period.

If the OP was to set timer to ON 06:30/OFF 08:30 allowing a constant 30 minute warm up period and the 12 minutes ignition for the other 1 1/2 hours that's a total of 42 minutes of the boiler running.

Back on at 16:00 and off again at 22:00 again allowing a 30 minute warm up period and 44 minutes for the other 5 1/2 hours that's a total of 74 minutes

Total boiler ignition time in a 24 hour period is 116 minutes or 1 hour 56 minutes so a whole hour and 4 minutes less then your way saving a 1/3 on the energy usage.

All the above assumes a fixed Kw being used by the boiler.

Now add into the equation these supposed expensive pointless controls that will incorporate weather comp and open therm technology that will modulate the burner while running to adjust flow temperature and adjust the warm up period to take into account for ambient temperatures that saving will only increase further probably in the region of an additional 5 - 10%

All the above is obviously only a paperwork exercise and there are too many variables but you can see how wrong you are with your assumption that running 24/7 is a better way of doing it.

@garmcqui If you could get a 400mm x 1600mm in there that would push you up to about 2.1Kw

Jon

...but it isn't working...because his room isn't achieving the temperature he requires in the set time period....

But all the other rooms are working and providing a comfortable living environment. It is only the living room which is the issue and that is not to do with the boiler or system controls it is down to what appears to be an undersized radiator of around 25%

I would be interested to see the graphs for other rooms if the OP has them?

I cant be arsed to get into heat loss values and how many Kw it takes to heat specific volumes right now but your way of heating 24/7 is not as economical as a timed period of heating. If that were the case why have billions of pounds been invested into timers, programmers, room stats, weather compensation, open therm? Surely the boiler would just need a room stat and an on/off switch?

Take the OPs original graph. The temperature does reach set point but takes a while. Once it goes off of an evening the room only loses 4.5C all night. How many Kw should it take to raise the temp back to 21C? compare this to your constant running throughout the night how many Kw do you use for something that is not required?

 

[Aquaheat]

I would also estimate that if you have an intelligent thermostat, it would be more efficient with constant heating.

But with an intelligent thermostat they are aware of your away periods and turn the heating off only coming on at a certain time (or geo location) before you return depending on the internal temperature, ambient outside temperature and required set point.

Yes you are right that heating should be set to constantly on if you have an additional timer in conjunction with it but ideally the timer will be removed so that the smart controls can take full control of the system.

Jon

 

[Aquaheat]

Threads like this are great because they help you work out who is worth listening to and who can safely be ignored.

Pray do tell

 

[endecotp]

No, not telling - but it should be fairly obvious; you can see who "liked" my bucket post, for example.

 

[Aquaheat]

No, not telling - but it should be fairly obvious; you can see who "liked" my bucket post, for example.

But your bucket analogy doesn't hold water (pun intended)

A heating system, or a house for that matter, doesn't react like that. With that you assume a constant and both would use the same amount of water but, and I'm only doing this to highlight your analogy, if I only needed that bucket to be full for 8 hours a day so allowed it to be empty for the remaining 16 hours and constantly topped up for that 8 hours who would use more water compared to filling for 24 hours constantly?

Obviously it doesn't work like that though as we are talking about transferring energy and while i don't argue that it will initially take more energy to raise the temperature in the short term to set point the "down time" savings will far outweigh the constant running. This is not just in terms of energy use but also the operating hours of the appliance and need for service and repair.

Jon

 

[JohnD]

to say it's more expensive goes against the physics...

Wrong.

What laws do you have in mind? Not Fourier's law, I think?

 

[hazetimesfive]

I would also estimate that if you have an intelligent thermostat, it would be more efficient with constant heating.

But with an intelligent thermostat they are aware of your away periods and turn the heating off only coming on at a certain time (or geo location) before you return depending on the internal temperature, ambient outside temperature and required set point.

Yes you are right that heating should be set to constantly on if you have an additional timer in conjunction with it but ideally the timer will be removed so that the smart controls can take full control of the system.

Jon

By intelligent thermostat I merely meant one that will apply smoothing to control temperature overshoot and dip.

 

[Agile]

It seems this kind of thread draws out those who ( wrongly ) imagine that heating 24/7 is cheaper than having shorter heating periods!

 

[endecotp]

No, not telling - but it should be fairly obvious; you can see who "liked" my bucket post, for example.

But your bucket analogy doesn't hold water (pun intended)

Aquaheat, tell me, in my bucket analogy who do you think would use the most water in the long term?
I know this isn't a perfect anlogy, but it's sufficient for me to work out whether the reader has a basic grasp of the laws of nature.

(BTW in response to one post, I'm not suggesting that water would ever be allowed to flow over the brim of the bucket. The water all comes out of a hole in the bottom.)

 

[endecotp]

Sorry, actually I see that you did answer the question and you think they both use the same. Which is wrong