View Full Version : Central Heating on all day?

21st Feb 2004, 06:14
In this little cold snap, and whilst I and Doris are out working all day, should we have the heating on to maintain warmth in the house all day, or should we set the timer to come on at or near our return at 5pm? Which is most economical?

21st Feb 2004, 06:24
Tis a subject which has troubled me too, Dubtrub. Last year, we changed fron having it on 6-8:30 am and 4 to 9 pm, to 6am to 9 pm, 7 days a week. Virtually no difference to the gas bill over the winter, but a more comfortable house. Combi boiler, BTW.

21st Feb 2004, 06:39
It's far too late in the day to ask all the right questions regarding your home's heat-conserving properties, heating systems etc. so why don't you just try this:

Day 1: Turn off all heating until you get back home. If it is uncomfortable, turn it on and time how long it takes to become comfortable.

Day 2: Set the timer to turn on the heating the required time it takes to become comfortable before you get back home.

:8 :zzz:

21st Feb 2004, 06:42
Which is most economical?
Not just comfort, but economy is the factor in the posters question, me thinks..

21st Feb 2004, 06:55
Well, the most economical would be to keep it off wouldn't it? :confused: I thought I'd correctly treated the matter of comfort with economy. :ouch:

21st Feb 2004, 06:58
No, not necessarily... takes a bloomin great load of gas to warm the house from cold.. not much to maintain the temp..

21st Feb 2004, 07:19
And why did the house cool down with heater off? Those joules went out the window or somewhere. You rightly state that it takes energy to reheat the place.

But more enegry will be lost if there is a larger difference between indoor and outdoor themperature. So there should be some economy in letting the house cool down during the day.

That said, I'd be surprised if you save enough cash to really matter.

The climate difference from one day, week, month, year to the next will probably obscure the differences if you ran experiments. OTOH, the US Wx Bureau publishes degree-day data, ie: number of days times number of degrees F below some arbitrary number (20C 68 F IIRC) on each day. The Met Office may do the same.

The main benefit to you might be in the good feeling of using less fosil fuel, etc, etc, etc.


21st Feb 2004, 07:19
Look, to maintain a stable temperature, you have to replace the heat lost with an equal amount. If your argument is that the average heating system is more efficient when producing 1500BTU compared to say 2500BTU you would be right. From a comfort standpoint, I would have thought that the average heating system would produce a comfortable temperature within a few hours after having been left off all day. They should draw the curtains closed too before leaving. :E

21st Feb 2004, 08:09
Well , you are all lucky you have heating at the moment

CIM got home from work today to a dead heating system and a very cold house.

Anyone know a good heating engineer who works for beer money?

21st Feb 2004, 08:30
If turnng off the heat at this time of year, when temperatures can still drop below freezing, there might be a problem with burst pipes when you get home. Never pleasant.

21st Feb 2004, 08:37
The answer is it depends!

Take an extreme, if you are away for 7 days the answer would clearly be that it would be cheaper to let the house get cold for those 7 days and expend the energy reheating to the desired temperature upon return.

On a shorter timescale it depends what the insulation properties of the dwelling are. If it is a well insulated house, in all respects, the difference would be marginal, so little heat would be lost.

If the house was uninsulated and appallingly draughty, then probably not, the heat lost during the day would be greater than the energy required to reheat the property at night.

Very much a case of trial and error. Take some gas readings in both cases, over two similar temperature days, and some simple sums should give the answer.

I do remember a friend leaving his heating on 24 hours a day about 20 years ago in the belief that it was more economical and also recall him needing a mortgage to pay the subsequent bill!

20 years ago, though, good house insulation was not as universally recognised as essential to comfort and ecology.

I am fortunate to have a large 4 bedroom house and I pay less than 60 per month all year round for heating, hot water and cooking, all by gas. During outside temperatures of less than 4 or 5 degrees I leave the heating on 24 hours purely for comfort, but I do have cavity wall insulation, very thick roof insulation and double glazing. For really impressive thermally insulated buildings have a look at Scandinavia, we in the UK are rank amateurs in comparison!

21st Feb 2004, 09:09
When I'm going to be away for an extended period I set the thermostat to 50 or 55 deg F. I figure that keeps the pipes melted.

While in inland Brit Columbia, Canada, some years ago I was impressed to see triple glazing. Or it looked like that.

21st Feb 2004, 10:45
Move to Queensland you don't need heating here.

And you can have cold showers - no energy wastage there - and they feel so good - just suck your breath away! Oh yes i am diverging....

And you can save energy by having solar power panels.
Coz we have this thing called sunshine here - but I guess most of you poor people don't know what that is......

Onan the Clumsy
21st Feb 2004, 12:58
While in inland Brit Columbia, Canada, some years ago I was impressed to see triple glazing Might have been double glazing with a storm window.

M Mouse has already beaten me to my point that after the house has cooled down to a steady state (7 days in his example) it becomes cheaper to wait and heat once. Up to that point, it should be equal to maintain the temperature or cool and reheat.

Using a differential calculus model, the constant heat method is merely a series of individual allow to cool and reheat methods anyway.

Of course all this is a moot point here in Big-D as it reached seventy degrees today - and remember...them's Texas degrees, so each one's a little bit bigger than normal :ok:

Anthony Carn
21st Feb 2004, 14:46
An unmentioned factor induces me to switch everything off when I'm out or sleeping...........what if the system goes wrong ?

A while back a neighbour went away for a few days and left their heating on a low setting. They returned to discover that there'd been a water leak, which was issuing forth as steam. The whole house was a sodden steam room.

It soaked the entire interior of their house, which needed new floors (chipboard melts when saturated), new dividing walls (Stramit swells when saturated) and new ceilings (plasterboard melts when saturated). That meant lots of new plumbing and electric wiring in the replaced walls etc etc etc. Furnishings and possessions were also affected, some terminally. This also led to a very inconvenient few months in a Guest House.

I'm not too keen on modern boiler design either. Those things are little nuclear bombs and not too far from meltdown. All to do with efficiency. Give me heavy "Victorian" design any day.

21st Feb 2004, 16:32
An unmentioned factor induces me to switch everything off when I'm out or sleeping...........what if the system goes wrong ?

A good point. However it is equally costly should the heating be off and the house be subject to below freezing temperatures for a few days!

I had the misfortune to recommend to a long haul stewardess friend living in a very draughty old house that it would be cheaper to leave her heating off when on a long trip. She did the very next trip just as we entered one of the longest cold snaps for years. Fortunately the weather was still below freezing when she returned and the burst pipes had not thawed! I repaired 7 bursts while eating much humble pie.

Modern heating systems are technically more complicated and much more thermally efficient than the older cast iron heat exchanger variety. To counterbalance your story I have seen the aftermath of a cast iron boiler exploding (I forget why but it was a new boiler/installation).

Nothing is foolproof and water sytems that fail dramatically will often do much damage. My guess is that the odds of it happening while out/asleep/away are minimal.

Anthony Carn
21st Feb 2004, 17:03
Tis definitely a problem if the weather is severe, especially when one has a dumb airline job demanding that home life be sacrificed for days at a time. Four nights away (my maximum) can be a worry. Tap supplies are still vulnerable, especially below suspended wooden ground level floors.

We turn the water mains off when we leave the place unattended, but there's still the tank full in the loft, plus the large volume in the pipes.

Watch the forecast, is all I can say, but everything off is my motto......not just for this topic either. :E

Paul Wilson
23rd Feb 2004, 05:28
You need to make sure next house has mains pressure water system. Turn off supply, turn on kitchen tap for a minute or so, no water in pipes. No water tank in loft, and the water actually comes out of the shower with some force, unlike typical British dribble.
New boilers also often have "frost stats" fitted, whatever you have done to boiler controls (short of turning off the gas) if the temp drops below about 3 deg C it fires up the heating.

Kaptin M
23rd Feb 2004, 05:44
It probably was triple glazing, seacue - a Belgian lass was saying she has it in her apartment.

23rd Feb 2004, 06:52
i used to have the heating on in the the morning and then again in the evening - but was really cold -
the following year i had the heating on 24/7 on a lower heat setting , turning it down at night and when i was out of the house - i was as warm as toast and the bill was only a fiver more over the winter quarter -
so in my humble opinion it makes no odds to the pocket!


23rd Feb 2004, 08:16
You need to make sure next house has mains pressure water system.

Sheer luuuxury! I recently decided to go down that course but despite having around 4 bar of pressure I have a flow of around 14 litres a minute! Something to do with a long thin pipe feeding the road, the end of which I am at! So stuck with good old British system.

Otherwise heartily concur.

Paul Wilson
24th Feb 2004, 00:06
I recently decided to go down that course but despite having around 4 bar of pressure I have a flow of around 14 litres a minute!

Thought about putting in a booster pump? Total cost should be around 200 depending on your plumber. Takes water out of tank and boosts flow and pressure well above normal, can actually empty tank faster than it will refill, but you'd need to take a LOOOONNNGG shower to run out.
For about a grand you could do the whole thing Thermostatic shower (set temperature and forget) big powerful shower head, and two or three extra nozzles to shower lower down.

Take a look at Aqualisa (http://www.aqualisa.co.uk)