Taking hours to heat the house

Therese1

Hi, 

I have a 5 year old gas combi boiler which is serviced annually.  

It’s always worked great.  However, this year it seems to be taking HOURS to heat the house.  Is this just because I am playing roulette with resisting putting it on and leaving the house to get too cold…11° today.  I switched the heating on at 2pm to 18° and yet by 8pm the Nest said the house was still only 15°.  

Is this normal (and I just haven’t noticed before?) or is there an obvious problem I need to get sorted? 

Thank heavens for my Dryrobe - getting my moneys worth out if it this year! : ))

ChaunceyGardiner

What is the radiator temperature on the boiler set to?

ariarnia

silly question but have you checked your radiators are getting hot? we check ours for cold spots and bleed them every year in autumn when we test the boiler is sill working as they can get air in there just as a normal part of heating and cooling the water. its easy to get a key online if you need one and there's lots of you tube videos on how to bleed them. 

if its not that then it could be your flow temp is turned down a little lower than your comfortable with after how youve changed your heating arrangements. you could try turning the temp up a little (the radiators will get hotter than they do now so the rooms will heat faster). 

if its not those two things then its past my knowledge and someone else will be abel to help i'm sure

[Deleted User]

  I switched the heating on at 2pm to 18° and yet by 8pm the Nest said the house was still only 15°.  

If you are playing around with your heating usage, is it possible that your very clever - and expensive - smart thermostat is getting confused? These devices take about a week to familiarise themselves with your heating pattern; home etc…

How much gas are you using per day in kWh? We just let our TADO thermostats do their own thing and usage yesterday and today is slightly below 30kWh - with the heating on from 6.45am to 9pm.

Apodemus

It is not unusual for a boiler to get turned down to a lower output temperature at its annual service, which might be too low to heat the house as quickly as you would like.  Ours is always turned back down to '1' by the service engineer, but really needs to be at '4' for the rads to get hot enough in the coldest months of the year (in an old single-glazed leaky house).

chris_n

Therese1 said:

Hi, 

I have a 5 year old gas combi boiler which is serviced annually.  

It’s always worked great.  However, this year it seems to be taking HOURS to heat the house.  Is this just because I am playing roulette with resisting putting it on and leaving the house to get too cold…11° today.  I switched the heating on at 2pm to 18° and yet by 8pm the Nest said the house was still only 15°.  

Is this normal (and I just haven’t noticed before?) or is there an obvious problem I need to get sorted? 

Thank heavens for my Dryrobe - getting my moneys worth out if it this year! : ))

If you let the fabric of the building get too cold it will take longer to warm up. How much longer depends on what the fabric is. If it is wood floors with stud walls it will not take as long as solid walls and floors.
However I would suggest there is more to it with only a 4 degree rise in 6 hours unless you have lots of draughts, single glazed etc.

chris1973

I had a similar property, it was heated by a 24kw (gas input) boiler and a variety of double and single radiators which got hotter than the gates of hell, yet it took 6 or 7 hours to heat the living room and bedrooms to anything close to being comfortable by which time it was time to go to bed. At todays rate a boiler with a gas input of 24KW would cost around £2.40 an hour for 7 hours which would be the best part of £17 per day, if the room thermostat wasn't reaching the desired temperature the boiler would just be burning gas continuously.

The house in question was a 1930's build, with double glazing, cavity wall insulation and so much loft insulation that there wasn't actually room to store anything up there, but it made absolutely no difference. Part of the problem was the 14ft high ceiling in the living room, and you couldn't reduce the height because of the bay window.

Sometimes you just have to accept that some houses are difficult to heat, and unless you have a ton of money to throw at it then there is no cheap or quick fix. I gave up trying to heat the entire house, it was just too expensive even when gas was 2p a KWH, so I just heated the room I was in using an Electric Heater.

The strange thing was, that a 6800BTU radiator would heat the room to about 19c in several hours, but a 2KW Electric convector heater would heat it to 20c in about 45 minutes, yet their outputs are equally matched, perhaps it was down to positioning of the heat source.

Even at todays rate, running a 2KW Convector Heater would cost 68p an hour running continuously, or £4.76 for a 7 hour period heating one room, that is a lot more attractive than the continuously running central heating cost of over £15 for the same period trying to heat the entire house and still being cold for the best part of the 7 hour period. I was living alone at the time, so it was easier to just exist through the Winter with one room heated at a time turning a heater off in one room and on in another as you moved around the house, if you were a family of six - not so easy.

ariarnia

chris1973 said:

Sometimes you just have to accept that some houses are difficult to heat, and unless you have a ton of money to throw at it then there is no cheap or quick fix. I gave up trying to heat the entire house, it was just too expensive even when gas was 2p a KWH, so I just heated the room I was in using an Electric Heater.

The strange thing was, that a 6800BTU radiator would heat the room to about 19c in several hours, but a 2KW Electric convector heater would heat it to 20c in about 45 minutes, yet their outputs are equally matched, perhaps it was down to positioning of the heat source.
easy.

if the electric heater works best for you i'm not going to argue (i've got a little oil rad for my office myself) but a third option might be a wireless thermostat you could move into the room and turning off the rads in all/most of the rest of the house. 

GCH is normally much cheaper than electric heating so the boiler working to heat less rads and the thermostat being in the room you want to heat (its normally in a hall somewhere) might work out cheaper. 

Astria

ariarnia said:

if the electric heater works best for you i'm not going to argue (i've got a little oil rad for my office myself) but a third option might be a wireless thermostat you could move into the room and turning off the rads in all/most of the rest of the house. 

GCH is normally much cheaper than electric heating so the boiler working to heat less rads and the thermostat being in the room you want to heat (its normally in a hall somewhere) might work out cheaper. 

I thought the same thing, and a 500W radiator in my office on a thermostat keeps the room toasty warm and the rest of the house is freezing, but when I finish the boiler is then on constantly for about 3 hours to get the house upto about 18c. If I instead set the house at 18c all day then it appears to cost about 5 kWh more per day but is so much more comfortable in the day. The oil filled radiator normally takes about 1 - 1.5 kWh per day, so at current rates that's 34p - 51p, so it seems equivalent.

Chrysalis

In houses that are slow to heat up and especially when you only using one room I have never understood the CH is cheaper argument, as you heating things you dont need heating, its inefficient.  I think some look at the cheaper KwH and just assume boom its cheaper without thinking about efficiency.

One of the reasons I dont use my central heating is it takes "hours" to start to feel it, so I am wasting gas on that transitional period.

Not all of us are in modern well insulated double glazed homes, with modern radiators and boilers, so that has to be considered.  I could heat my room in under 10 minutes with a portable heater, it would take probably 3-4 hours minimum to get even close to that with central heating.

Some houses/rooms just need a powerful burst of heat to get them warm which overcomes the heat leakage rather than a gradual supply of heat.

chris_n

Chrysalis said:

In houses that are slow to heat up and especially when you only using one room I have never understood the CH is cheaper argument, as you heating things you dont need heating, its inefficient.  I think some look at the cheaper KwH and just assume boom its cheaper without thinking about efficiency.

One of the reasons I dont use my central heating is it takes "hours" to start to feel it, so I am wasting gas on that transitional period.

Not all of us are in modern well insulated double glazed homes, with modern radiators and boilers, so that has to be considered.  I could heat my room in under 10 minutes with a portable heater, it would take probably 3-4 hours minimum to get even close to that with central heating.

Some houses/rooms just need a powerful burst of heat to get them warm which overcomes the heat leakage rather than a gradual supply of heat.

If the heat is getting out as fast as you are putting it in it can never be efficient. If you can heat it very quickly with a higher powered heater it can make you feel warmer even as the temperature starts to drop again.