How long to heat a room from 16c to 21c?

[SteveZodiac]

As said depends where the stat is assuming the rads are the correct size.
If the t/stat is cycling it will take a long time.
Is the t/stat in the room you are measuring?

The thermostat is in the room I'm measuring. How can I tell if it's cycling?

In my book a room should warm up from stone cold to nice in less than half hour.
Your problem is probably a combination of:
draft
heat from rad cooling off against cold window
often heat getting trapped behind curtains
improper balance
soil
unsersizing

Draughts may be a problem, but do we keep the door closed.
The curtains are usually closed by the time the heating is on full, and I always make sure that no heat is getting trapped behind them.
The system is probably out of balance, but the rad does get very hot anyway.
What do you mean by soil?
How do I work out what the correct size rad should be?

In my house never. If boiler is on 80 degrees all day we can achieve 18.5 max if that is of any help to you.

It's a matter of aclimatising.

Are you saying your system won't heat above 18.5c at all even if it's on all day? Sounds as if something is wrong there.

I take your point about aclimatising but I'd like to know if I'm throwing gas at a problem I'm never going to solve if you know what I mean.

i.e 1hr 45mins from 16 - 21C. (slower than I thought actually).
For info, the outside temp was 6C at the time.

One of the reasons I'm fitting a thermal store actually, heatup times are slow.

Much better than mine, so there's something wrong somewhere as we seem to have similar sized rads. What's a thermal store?

The official definition was if the OUTSIDE temp was minus 1 then the house should be at 21 degrees inside in an hour .

That's what I wanted to know, which means I've got a problem somewhere.

Have you considered larger radiators... normally helps.

Is your room stat in a warm area i.e. near a rad. If it is then it may think the house/room is up to temp. when actually it isn't.

Haven't had the thermostat long, and tend to keep it on the coffee table in the middle of the room. It's definitely not near a rad.

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Thanks for all of your comments. How hot should a rad get at full blast?

 

[jon26]

Thanks for all of your comments. How hot should a rad get at full blast?

About 80degC.

 

[sim17]

"how long should a room about 12' by 13' with solid walls and a bay window take to heat up from 16c to 21c? I know it's been cold recently, but it's taking 4 or 5 hours or so which seems excessive. The radiator, which is a double 160cm x 44cm (5'3" x 1'5") located in the bay, gets very hot and the boiler is a Worcester 28CDi. "

Almost exactly the same as my front room (added to which it is on the outside of the house ie no party wall). To which I've just had a 5.6kW gas fire added (Faber, modern, efficient as gas fires get). My boiler is 28kW and new. The rad is double and the width of the bay. It gets hot. My room takes a long time too, and struggles to climb above 20deg at all, and I'd like still like to improve it. This is my thinking:

My bay window is single glazed and large (box shaped glazed on 3 sides), I'll be having DG fitted (as a renovation, not PVC). In the meantime or perhaps instead how about really thick curtains, or even put loft insulation wool between curtain and lining, or as additional lining layer. Then make sure curtains fit well to cover all gaps (but not over radiator).

Apart from the bay I think the main problem is solid walls - I have solid wall brick 9in. On the external wall I have lined internal face with gyproc thermaline 60mm - big upheaval and mess, part of replastering which needed doing anyway. It makes a difference but the bay is still the big problem it seems. In a bedroom I've done the same but all external walls insulated and only small DG window - that's really cosy now.

Finally check the floor and other areas for drafts. there is insulation under my wooden floorboards (and no carpet), but actually on really cold days I've worked out there are corners and gaps where cold draft circulating through air bricks under floor are getting through. Insulate these areas and/or seal up properly (again can be upheaval and messy, boards up or get under there somehow).

For comparison: with the gyproc thermaline on one external wall the room can still take 2-3 hours to get to 20degress (from around 14, 2-3deg outside). With the fire on this reduces a little, but not as much as I expected. So I'm saving for an expensive window renovation job.

I know 17-18degree is perfectly comfortable often, and many times I live like that. But when elderly relatives come round, or more "sensitive" types, and we are more static in an evening (not talking about hot blooded teenagers here), I would like to be able to get to 21-22, and without having to "stoke" the whole place for 24hours before hand.

Interested in any other views people have, but when I come to buy a house again I definitely will not buy with solid walls and I'll be tending towards modern rather than old even though I don't like the look so much. Boilers can be replaced for small £ks and in a day or two. Upgrading internal wall insulation is seriously more bother and mess, best done before you move in. Window renovation is seriously expensive.

 

[D_Hailsham]

Haven't had the thermostat long, and tend to keep it on the coffee table in the middle of the room. It's definitely not near a rad.

Ah! so it's a wireless stat is it??
Which make/model stat do you have?
Do you have TRVs on the rads in the room with the thermostat?

The official definition was if the OUTSIDE temp was minus 1 then the house should be at 21 degrees inside in an hour .

Which "official" body laid down that definition of Central Heating and when?

 

[SteveZodiac]

Ah! so it's a wireless stat is it??
Which make/model stat do you have?
Do you have TRVs on the rads in the room with the thermostat?

Yes, a Honeywell CM927. I removed the TRV from the rad in the room when I got the thermostat.

My bay window is single glazed and large (box shaped glazed on 3 sides), I'll be having DG fitted (as a renovation, not PVC). In the meantime or perhaps instead how about really thick curtains

My bay is also box shaped but upvc double glazed on 3 sides, and is the only outside surface. The room is nearly north facing though, which doesn't help. The curtains are cill length, good quality and pretty thick. I make sure heat doesn't get trapped behind them.

Apart from the bay I think the main problem is solid walls - I have solid wall brick 9in. On the external wall I have lined internal face with gyproc thermaline 60mm

My walls are the same, but none of them are external. The room does heat up a bit more quickly now probably because of the heat that's been pumped into the walls over the past few weeks.

Finally check the floor and other areas for drafts.

We always try to keep the door closed, but I've come to the conclusion draughts must be a major cause of the problem. The floor should be OK as the the floorboards were boarded over before a carpet with good quality underlay was fitted. There is a gas fire in the fireplace which we don't use much because it's inefficient, but there are gaps around it which creates a draught. Not sure what to do about that. Any suggestions? When I first posted I should also have mentioned that we have a conservatory with no doors to the dining room, linked to a kitchen extension which also has a conservatory type roof to maximise the light. The dining room and kitchen extension would be very dark otherwise. The particularly cold weather this year has meant these areas struggle to get really warm as well which creates draughts, and I don't know what to do about it.

Interested in any other views people have, but when I come to buy a house again I definitely will not buy with solid walls and I'll be tending towards modern rather than old even though I don't like the look so much.

When we make our (hopefully) final move we'll buy older only if already well insulated I think.

 

[JohnD]

I should also have mentioned that we have a conservatory with no doors to the dining room, linked to a kitchen extension which also has a conservatory type roof

heat loss through conservatories is immense. You cannot expect to get them warm, nor any room which is open to them. there ought to be doors to close off heated rooms from conservatories.

you will be almost as cold as if you had a big hole in the wall open to the garden.

 

[Agile]

Its long been the specification for central heating that with -1° outside the system should maintain + 21° inside.

That will explain why some systems cannot achieve that inside temperature when its below - 1° outside.

I have never seen a defination of the time taken to warm up the inside to 21°. But I would agree that it would be sensible if that situation was achieved within an hour. I would also expect about 18° after 30 minutes to make it start to be comfortable.

Tony

 

[SteveZodiac]

Its long been the specification for central heating that with -1° outside the system should maintain + 21° inside.

That will explain why some systems cannot achieve that inside temperature when its below - 1° outside.

That sounds logical to me and may well be my problem, although I haven't been checking what the outside temperature has been when the room's been +16°c. I wonder the insulation specification is in order to achieve +21° inside when it's -1° outside? I would have thought the better the insulation the better the system could achieve +21° with less than -1° outside. I've heard somewhere that if houses were built to Swedish standards of insulation here then we would hardly need any heating at all during the winter.