running central heating continuously or not?............That is the question.!!

[chirpy]

hi,

After a recent service of oil heating system,where I use a simple plug- in timer switch to stop at night and re-start in morning ,as boiler is in an outhou se ,adjoining the kitchen,the plumber advised this was wasteful of oil.

His argument is that I am re-heating cold water each morning and this takes more oil than if I ran the heating continuously all night with just 1 radiater open.

What do the experts think??

 

ALSO SAID IWOULD BE BETTER OFF TO HAVE A THERMOSTAT IN THE HOUSE AND EVEN TO SAVE CABLING ,A WIRE FREE PROGRAMMER COSTING 220EURO.

THANKS

[Alex H]

I think it depends.........

Our heating system in the UK is gas and we do not run it overnight. This is due to the simple fact that we would have to either

a) lower the thermostat at night (and remember to set it back during the day)

b) have it on low all the time

Our oil system in France is far more sophisticated

It will maintain a set temperature during the day (usually 20 - we only have 3 rooms at the mo')

It will maintain a lower temperature through the night (usually 12) so it does not come on very often in the winter and hardly at all in the summer (only maintaining hot water temp)

If you run the heating all night with one radiator open - does that mean you have to switch the rest off before going to bed? (and open them up in the morning)

A thermostat in the house is an absolute must, I think, but the saving on cabling is a bit overpriced in this case (sorry, I can't do smileys)

Is your boiler in the outhouse well insulated? because it may be coming on due to it's temperature rather than that of the house

[Sunday Driver]

We have a de Dietrich oil fired boiler with a fully automated control system which allows us to set both daytime and nightime temperatures, together with an external temperature sensor which is mounted on a north facing wall which acts as an additional temperature control .  That means we never have to touch the system and outside of summer, if it's mild out, the radiators automatically stay cool. Like TP, our overnight temperature is set quite low and rarely comes on.

Compared to our previous old boiler which ran on a simple mechanical timer, our oil bill has been reduced by 60%.

 

[AnOther]

I think that there are too many variables to be able to answer such a question conclusively.

My own thoughts, running an oil system with a simple ON/OFF (electronic) timer and no thermostatic control other than the boiler setting itself, are that it's probably better to just run it up in the morning.

Assuming zero heat losses in the boiler then clearly neither regime will have an advantage over the other as takes x amount energy to raise the water to a given temperature. No boiler has zero heat loss though so on that simple basis alone I don't see how having it on overnight, where the boiler would be cycling through the range of it's thermostat, even if only once or twice, could be any more efficient than a one shot in the morning.

A practical way of comparing the two regimes in a quick and reasonably meaningful way would be to monitor the boilers electricity consumption with one of those plug in jobbies. It's very simple equation then, less electricity used = less oil burnt = more efficient.

Alternatively if you have a semi transparent plastic storage tank you could run it each way for a set number of days carefully measuring the oil consumption.

I'm not sure why the suggestion that you run 1 radiator though, all that will do is increase the losses leading to cycling and higher consumption.

A themostat in the house would be a good idea but equally effective I think would be thermostatic radiator valves.

[woolybanana]

IMNVHO you need to be able to isolate different rooms and have thermostat control for each, hence on the radiators. Thus all those unused guest bedrooms are kept at a lower temperature when not needed whilst rooms such as childrens bedrooms can be kept hotter.

Central house thermostats' successful operation depend on the house being draftt free which is not likely in some of the old piles which Brits have, and can end up costing a lot more in fuel.

Ideally, the boiler should be under the house so that the waste heat rises.

[Jonzjob]

Everyone is assuming that your system is a radiator one and not underfloor? You didn't say?

We have the same mark boiler as you SD complete with the radio remote controller and condensing boiler, but LPG fired. Lovey bit of kit and uses about half of the gas the old systen used. When (!!!) we have to move to a smaller place we will be looking for underfloor again. It far outstrippes radiators nailed on the wall. Complete warmth and the ability to walk around barefooted summer or winter!

[BIG MAC]

Water heating in the morning etc? Why not install a thermal store and heat it by the most economical means whether this is off peak electricity or oil? Hot water on tap and the boiler will cycle only as required Incidentally you could install wireless controls so that the boiler will fire only when heat is called for and off peak electric not available by a simple combination of timer and thermostats.

 

[chirpy]

thanks forall replies.

I have a jotul wood stove in living room ..no problem and 2 radiaters which hardly used.

The rest of house has an oil boiler in a  stone wall attachment to side of house.,with oil tank in bund area.

The hot water is from electric boiler.

There is kitchen,living room,3 bedrooms and bathroom on ground floor of an original barn built1850.Height about that of a as story house,not a gigantic barns.

Oil system installed about 15 yrs .ago by previous owner with radiater in all rooms and kitchen.

What ia a thermal store going to cost and ancilliary equipment as I am retired on small pension and close to73years young!!!!

Will I save the expenditure over a short time scale??/only a guide...I realise that it depends how hot you want living areas and number of persons using facilities.However there is only two of us with perhaps a 2week visit in summer by friends when oil heating not used.

THANKS[8-)][:D]

.

 

[WendyG]

Hi there

When bought the house as second home back in 2002 found that the massive oil burner needed to be on continuously to heat the hot water (and seemingly the radiators) to the kitchen and bathroom.  Also there was a switch which meant it would only heat the upstairs radiators.

As the house is quite long and radiators and pipes are large we took the hot water system off and now use ballons.

There are no timer controls on the system and when questioned our French neighbours say "but you just leave it on all the time"!

There are two wood burners in the house, one in the kitchen and one upstairs so really primarily rely on those, switching on the boiler late afternoon and switching off mid evening (the radiators particularly upstairs stay hot for at least 2 hours).  This seems to be the most economical use of oil.

Good luck and keep warm.

WendyG

 

[chirpy]

wendy ..How do you put hot water into a balloon???[:D]

What exactly is a ballon?[8-)]

[suein56]

[quote user="Ab"]

What exactly is a ballon?[/quote]

A hot water cylinder, usually, but not always, heated by electricity.

Sue

[andyh4]

[quote user="AnOther"]

I think that there are too many variables to be able to answer such a question conclusively.

My own thoughts, running an oil system with a simple ON/OFF (electronic) timer and no thermostatic control other than the boiler setting itself, are that it's probably better to just run it up in the morning.

Assuming zero heat losses in the boiler then clearly neither regime will have an advantage over the other as takes x amount energy to raise the water to a given temperature. No boiler has zero heat loss though so on that simple basis alone I don't see how having it on overnight, where the boiler would be cycling through the range of it's thermostat, even if only once or twice, could be any more efficient than a one shot in the morning.

A practical way of comparing the two regimes in a quick and reasonably meaningful way would be to monitor the boilers electricity consumption with one of those plug in jobbies. It's very simple equation then, less electricity used = less oil burnt = more efficient.

Alternatively if you have a semi transparent plastic storage tank you could run it each way for a set number of days carefully measuring the oil consumption.

I'm not sure why the suggestion that you run 1 radiator though, all that will do is increase the losses leading to cycling and higher consumption.

A themostat in the house would be a good idea but equally effective I think would be thermostatic radiator valves.

[/quote]

 

I think your analysis omits the overrun/overshoot effect.

When the set point for the control changes upwards, the boiler starts to work hard to reach the new set point.  Becasue of the the flow of water round the system this takes some time and inevitably by the time that the return water has reached the set point where the boiler would shut off, the input water is considerably above set point.  The bigger the change in temperature from night to day (and you can't really get bigger than off to on) the more likely the boiler will over run the set point.

 

This can be programed out with expensive and clever controls - but they mean it will take longer to reach the control temperature.

 

At least that is what our plumber explained when we questioned on exactly the same point about whether to run at night and at what temperature - admittedly our sustem is underfloor, so the heat sink involved is extremely large, and the ability to over run that much greater.

[AnOther]

Surely if overshoot is going to occur then it will do so whether on overnight or just once in the morning won't it ?

Also I'm at a loss to understand how the water in any part of any system can exceed the set point temperature by any significant degree (sic), how does that work ?

Furthermore, whilst the heat sink effect of underfloor systems may make it economical to keep them flowing overnight at a reduced temperature, traditonal radiator systems are usually turned off hence there is no flow and consequently less work for the boiler to do to maintain it's set point. This is offset of course by the extra work required in the morning to bring the whole property up to the desired temperature.

As I said, too many variables......................[;-)]

[BIG MAC]

Sadly you are unlikely to reap the benefits of a thermal store.

Instead I would take the view that heat loss is as much if not more of an issue than heat generation. Leaving your boiler in when not needed is wasteful but probably advice given in a kind hearted way by someone concerned that you get chilly.

The most cost effective thing you can do is Insulate everything you can including heating pipework where it runs beneath floors etc...(Dont scrimp it's a false economy)

Insulate ceilings and walls if possible... Lofts certainly and underfloors where possible ie. if you have a cellar then EPS (Expanded Polystyrene Slab) will fit snugly between floor joists just remember to get flame retardant stuff.and consider undercloaking the joists with plasterboard.

Doors and windows secure and weather tight, double or secondary glazing are good and winter weight curtains help (Even with double glazing).

Use a 'flue balloon' if not using the Jotul to block the chimney

Draught excluders are good and cheap!

Heat generation is best putting heat where you want it when you want it

Wireless Room stat in Lounge (Away from woodburner and rads ...on a 'cold wall')

Wireless room stat in Bedroom (Cold wall away from Rads)

Frost stat in boiler house same wall as air intake may be best

Two or more zone wireless programmer in the kitchen and four port  motorised valve and wireless valve head.

The above should allow you to set your heating to run on timed to heat the downstairs (Zone 1) early in the day  and again in the afternoon (You can always over-ride to permanent if there's a need) The upstairs (Zone 2) could be set for a couple of hours in the evening (The thermostat will stop the system if set temperature is achieved)

Frost protection will see the boiler cycling in extremely cold weather this will prevent pipes freezing and keep trace heat in the system prior to coming on full chat in the morning.

If your house is insulated and warm then to have the boiler running constantly is just sending money up the chimney arguably money which you could spend on controls or insulation.

The above scenario would allow you to run your woodburner and its rads (I would consider putting one in the bedroom if it's upstairs as this would promote a good gravitational circulation) Ypu could consider  having a hot water cylinder heated by the woodburner and connected to the bath when the wood burner is on the oil fired heating will shut down 1 or both zones so long as the set point is being maintained)

I cannot comment on French costs but at UK prices the controls would cost about £800 fitted I would guess. And Insulation would depend upon what you have and where you put it.

Last time I was quoted on a thermal store it was 3500€ for a 3,000 litre (3 Tonne) item ....you will recover your money quicker on the Insulation controls etc. because you will need to heat less.

I hope this isn't too rambling and is a help. There will be those who more than likely would want to shoot it full of holes but what else is there to do in a meaningless void? ;-)

[boussagues]

Hi, I also have a De Dietrich system that I have been running since 2002. It is a 96Kw boiler with al the internal and external sensors. We get through 2500 litres of fuel in 12 weeks and that is only heating a very small portion of the place. I have now put it on a timer as the boiler will switch on when the boiler temperature drops to 40c even when it is in night mode. I have now put it on a timer and that has cut the fuel consumption as the boiler temperature only goes down to 50c and it runs for 4 minutes to get it up to working temperature again..

[AnOther]

[quote user="boussagues"]We get through 2500 litres of fuel in 12 weeks and that is only heating a very small portion of the place.[/quote]Thats outrageous [:'(]

My 1995 vintage 95kw Ferroli, the only source of heat and hot water bar the occsionally used wood burner, only gets through 1500-2000lt/pa in a 4 bedroom house and we're far from frugal with it.

Similar to this

[img]http://i.ebayimg.com/04/!Bf0E7vw!Wk~$(KGrHqQH-C4ErflHGWM+BLCvIyOpvg~~_3.JPG[/img]

[boussagues]

Are you sure it is not a 9.5Kw/h, 95Kw/h seems an awfully large boiler for a 4 bedroom house, that is 324,000 BTUs and a 200m2 - 250m2 house normally needs only 34,000BTUs. We live in a 12th Century Castle with stone floors and walls and therefore no insulation with ceilings between 4 and 6 metres high, although we only use a portion of the 750 m2.

[AnOther]

Actually it's probably 95,000 BTU which is around 28kw, I was working from (feeble) memory [blink]

PS: You didn't say it was a 12th century baronic pile !