Most efficient way to use radiators in apartment?

VonLuck

Over the past month I've noticed my apartment getting noticeably colder. I normally have all my radiators off for most of the year because it's pretty well insulated and get some residual heat from adjacent apartments on all sides, above and below.

So when turning on a gas central heating system, is it better to just have the radiators on in the rooms you're using or heat the entire home as a whole? On the one hand I think just having a rad on in the bedroom (where I have a home office at the moment) that all the energy will go to that room and heat it up quicker. On the other hand, if I heat the other rooms the heat might be shared between the rooms, especially if I leave doors open.

I was also thinking that a single rad can only get so hot and if the gas boiler is on for an hour it's going to use the same amount of energy if I have one rad on or if I have 5.

Also strangely enough my living room is generally 3-4 degrees warmer than my bedroom, even without any rads on and am not sure if turning the rad on here will have any benefit.

Any tips?

10-10-20

I think you've found the most efficient way to use the radiators - that is to use your neighbors radiators instead.
I presume you have TRV's fitted to each rad? You could consider having some unused rooms at a lower temperature, say 17 degrees and then the main ones at 20 degrees. That way you lessen the losses but continue to have background heat in the apartment.

VonLuck

Yes, they all have TRV's. The temperature in any one room never really drops below 17 degrees. I find that in around 20-21 is a comfortable temperature if you're in a room for an extended period of time.

My living room generally stays at 20 degrees without any radiators on.

It takes some time for my bedroom to get to 20 or 21 degrees though so would have to leave the heating on for a while to get up to that temperature. I thought if I left the heat on for a shorter period of time but in multiple rooms that I would get the benefit of residual heat at no extra cost.

Lets say that I only need to heat one room. Am I right in saying that having a boiler on for an hour just for a single radiator is much less efficient than heating multiple radiators for an hour? What I mean by that is wouldn't there be more overall heat output from 5 radiators on for an hour than just 1, yet using the same amount of energy? I would assume that there's a limit to how much heat output there is from a single rad.

John.G

Pre covid, I used to have my heating on from 0900 tp 1000, 1200 to 1300 and 1530 to midnight (10.5 hrs/day), now its on from 0900 to midnight continuously, (15 hrs/day), we keep bedrooms at 17/18c and downstairs 22/23C, oil consumption increased from ~ 7 litres/day to 10 litres/day (72kwh to 102kwh) but of course a much more constant warmth in the house, downstairs is still 18/18.5C in the morning but no way is that comfortable enough for us.

Calahonda52

VonLuck wrote: »

Yes, they all have TRV's. The temperature in any one room never really drops below 17 degrees. I find that in around 20-21 is a comfortable temperature if you're in a room for an extended period of time.

My living room generally stays at 20 degrees without any radiators on.

It takes some time for my bedroom to get to 20 or 21 degrees though so would have to leave the heating on for a while to get up to that temperature. I thought if I left the heat on for a shorter period of time but in multiple rooms that I would get the benefit of residual heat at no extra cost.

Lets say that I only need to heat one room. Am I right in saying that having a boiler on for an hour just for a single radiator is much less efficient than heating multiple radiators for an hour? What I mean by that is wouldn't there be more overall heat output from 5 radiators on for an hour than just 1, yet using the same amount of energy? I would assume that there's a limit to how much heat output there is from a single rad.

Do you mean efficient or economical?

One rad will heat up until the return temp to boiler is high enough to cut out the boiler so the driver is heat demand/output, not elapsed time.
5 rads will use 5 times more energy assuming same size and same delta T and take loner for return temp to cut out boiler

zell12

"and get some residual heat from adjacent apartments on all sides, above and below."
Have you no windows at all?

VonLuck

Calahonda52 wrote: »

Do you mean efficient or economical?

One rad will heat up until the return temp to boiler is high enough to cut out the boiler so the driver is heat demand/output, not elapsed time.
5 rads will use 5 times more energy assuming same size and same delta T and take loner for return temp to cut out boiler

Not totally up to speed with how boilers operate but I thought that if you turn it on for an hour that it runs continuously for that period of time. But what you're saying is that it shuts off once the water reaches a certain temperature? If so, then yes I was wrong in my assumption.

zell12 wrote: »

"and get some residual heat from adjacent apartments on all sides, above and below."
Have you no windows at all?

Apartments above, below and on 3 sides. Have only one side "exposed".