how quickly does your house heat up

northernsoul

Many people on here i have noticed question how long and how much gas people use to heat up their house, especially when heating up from cold ie no heat for several days.
Once when i came back from a winter holiday it took 2 or 3 days to get up to 21C with the heating on all day. The house was i think about 8C to start with. I still find this hard to believe but believe the walls have a great effect on the ability to heat up.
My house is an 100 year old uninsulated 2 bed and attic bedroom terrace house, 2.9m ceilings (11ft 5inch), 4.3sq m (14ft) rooms (minus stairway). Double glazed and the only insulation is 50mm kingspan in the attic ceiling.
This morning i monitored the heating
During the night the digital thermostat was set at 16C
At 7.20am the thermostat temperature asked for 20.5C
30 minutes later it had reached 18C
1 hour later it had reached 19C
90 minutes later it had reached 19.5C
120 minute later it had reached 20C
By 150min (probably sooner) it reached 20.5C
The outside temp was 0C and it used 1.99m3 (approx 22 kWh) of gas in the first 2 hours.
My boiler is a Vaillant 837, gas rate 4m3/hour.
I am interested in other peoples experiences and would appreciate if people said if their comments are based on actual readings like mine or a general 'thought' what they think it warms up like.
Thanks

justjohn

Never measured, I am in a 1800's house. 5 bed end terraced.Walls are rubble walls 1.5ft ish thick. dg and on spec insulation in loft.

boiler setting is turned down too half setting. I know the rads are not the correct size for the room. House was converted from coal to oil.(

We have trv's on all rads. If you have not got them I would suggest you get them as this will effect fuel consumption. Remember the thermostat is taking the temp from the room it is in.

We will be upgrading the rads and implementing energy saving methods this year.

There is not much we can do about our walls, as we do not want to insulate inside or out.

northernsoul

hi justjohn
Got trv,s on every rad bar the one near the thermostat. Got 7 rads. All trv's need to be on max apart from the 2 bedrooms which are set at 3. The attic bedroom needs to be set at max as well (coldest room in winter, hottest in summer!)
Boiler is set at 3/4 as i do feel it struggles to get up to temp if lower in these temperatures of 0C or below. Think flow temp is about 65-70C. (will have to wait until tomorrow morning i guess to check this now)

Frogletina

I have a Worcester Boiler. Foolishly when I went away last Monday I turned the heating completely off (I have underfloor heating)

I came back last night to a freezing house and turned it on to its highest setting, left it on the 'on' setting and this morning it was only at 16 degrees by the thermometer in the sitting room. (Did not check heat last night and put a fan heater on for the first time ever here)

It has just crept up to 18 degrees.

MoneyMate

:beer:Hi interesting subject, call me SAD but I check the Min outside & Min inside temp over night, we live in a Bungalow hopefully well insulated loft and walls, double glazing no heat source apart from a Worcester Combi boiler.

Recently the overnight inside temp goes down to around 16 c, heating in day is set at 22 c, comes on at 9.40am, goes off at 11pm, this morning from overnight low of 16 c it is currently 20.5 c .

katejo

i have a Vaillant which is set to maintain at least 15 degrees during the night. I have a remote control thermostat which is set to raise the temperature to between 18 and 21 (dependng on weather). it works pretty well but i don't have exact stats to give you. this is in a Victorian terraced house with double glazing and roof insulation.

justjohn

northernsoul wrote: »

hi justjohn
Got trv,s on every rad bar the one near the thermostat. Got 7 rads. All trv's need to be on max apart from the 2 bedrooms which are set at 3. The attic bedroom needs to be set at max as well (coldest room in winter, hottest in summer!)
Boiler is set at 3/4 as i do feel it struggles to get up to temp if lower in these temperatures of 0C or below. Think flow temp is about 65-70C. (will have to wait until tomorrow morning i guess to check this now)

Sounds like rads are too small(or temp too low, however think its your rads,assuming theres no other probs). ...all new rads in our house click on and off as they should

However the old double rads do not(doubles with no fins), as the output is not high enough. Our house used to be run on a stove with back boiler. I am guessing the temp of the CH water was a lot higher(when run on coal) than the temp I currently have boiler set at.

We have 2 attic rooms, 1 has a rad in and the other does not. similar too yours roasting in the summer. However the room with no rad in is cold. Other attic room has a new rad in, clicks on and off as it should.

We have 13 rads...lol 5 being old style rads (imperial), each room they are located in has a problem getting up to temp with current settings on boiler. At least 3 are due to be changed asap.

BTW our trv's are set at 3.5 in bedrooms and 4ish in livingrooms. Any room that has old rads in trv's are set full whack lol

northernsoul

justjohn
The central heating system is 4 years old. I specified the rad sizes based on the previous rad size performances and online calculators. Interestingly the online calculators varied quite a bit so i chose the upper range. The Stelrad compact i have outputs 9455btu for my lounge. Today i have used 2 calculators, one on diy.com and a new one 'stars' from Stelrad. DIY suggests 6022btu and Stelrad Stars 12900btu ! Dont like these calculators, so much difference and difficult to input your wall type etc.
So maybe, although i went for the upper btu suggestions and bigger than my old rads, they still might be undersized as you suggest.

HappyMJ

northernsoul wrote: »

justjohn
The central heating system is 4 years old. I specified the rad sizes based on the previous rad size performances and online calculators. Interestingly the online calculators varied quite a bit so i chose the upper range. The Stelrad compact i have outputs 9455btu for my lounge. Today i have used 2 calculators, one on diy.com and a new one 'stars' from Stelrad. DIY suggests 6022btu and Stelrad Stars 12900btu ! Dont like these calculators, so much difference and difficult to input your wall type etc.
So maybe, although i went for the upper btu suggestions and bigger than my old rads, they still might be undersized as you suggest.

What temperature is the boiler set at? The rad's will only output that much heat if the boiler is set to maximum. They will not output that much heat if you set the boiler to the most efficient setting which technically is low. If you don't mind sacrificing a few percentage points of efficiency then I'd set the boiler to a higher setting.

A12,900BTU rad should heat an average sized room very quickly.

justjohn

HappyMJ wrote: »

What temperature is the boiler set at? The rad's will only output that much heat if the boiler is set to maximum. They will not output that much heat if you set the boiler to the most efficient setting which technically is low. If you don't mind sacrificing a few percentage points of efficiency then I'd set the boiler to a higher setting.

A12,900BTU rad should heat an average sized room very quickly.

That's why you should oversize

justjohn

northernsoul wrote: »

justjohn
The central heating system is 4 years old. I specified the rad sizes based on the previous rad size performances and online calculators. Interestingly the online calculators varied quite a bit so i chose the upper range. The Stelrad compact i have outputs 9455btu for my lounge. Today i have used 2 calculators, one on diy.com and a new one 'stars' from Stelrad. DIY suggests 6022btu and Stelrad Stars 12900btu ! Dont like these calculators, so much difference and difficult to input your wall type etc.
So maybe, although i went for the upper btu suggestions and bigger than my old rads, they still might be undersized as you suggest.

Depends on insulation,outside walls, windows, underfloor insulation, rooms above.

Remember rad outputs tests are done at delta-t50 or t60. So if boiler is turned down output will be less.

"Delta-T
Manufacturers publish the nominal heat output for each size and type of their radiators. Obviously the hotter a radiator is the more heat it gives out, so for the specification of a radiator's heat output to be meaningful this factor must be incorporated. Since a water cools on its passage through the radiator the mean of the flow and return temperatures is taken, and from this is subtracted a notional room temperature of 20°C, and the difference, known as Delta-T, should be given in the radiator specification. For non-condensing boilers which might have maximum flow and return temperatures of 90°C and 70°C respectively this gives a 60°C difference, and radiator outputs specified for these conditions are known as "Delta-T 60". For more modern installation with high-efficiency condensing boilers flow and return temperatures are likely to be around 75°C and 65°C giving Delta-T 50.
To convert Delta-T 50 to Delta-T 60C multiply by 1.2675"