Cutting down heating costs

[ss]

We currently run a gas central heating system of 15 radiators with two of them turned off (frost setting). My wife is out all day and I am in all day and mostly sit in a room 12 x 6 feet, odd visit to kitchen loo etc. Would I be cheaper to turn off the central heating completely until say an hour before my wife comes home (away 7am - back 6pm) and just use say an 800 W halogen type electric heater in the small room I use. I suspect the heater will be on most of the day but would this be cheaper heating one room electric than most of the house gas? I normally have the thermostat set at 17C for most of the day and just let it run.

Any thoughts on this

[John Rumm]

Take a gas meter reading in the morning and again at the likely "switch back on" time. Then you can see what you are using for a given day, and make an informed choice.

[David WE Roberts]

Looking back at the previous thread, why not have TRVs in all rooms set to frost protection and just have your room with the TRV turned up? However that involves a lot of turning up and turning down. Although I am not sure why the two of you need (15-2)=13 radiators to heat your living space unless you have a lot of very large rooms or work on Mad Hatter principles. :-)

I suspect the sophisticated answer may be a zone valve for your room.

Seems a shame to have gas central heating and then use electric - does your house heat up quickly if you only run the CH morning and evening?

As a compromise you could say run the CH at 14C and top your room up with a heater.

Cheers

Dave R

[harry]

Very likely yes.

[ss]

2 in kitchen 2 in downstair hall 1 in my room 3 in lounge 2 1 each two toilets 2 in used bedroom 1 in upstair hall

[Another John]

Awful thought, but I often do this myself: have the heating off all day, and wear a wooly hat (pulled down over your ears, which otherwise will act like large heat-dispelling fins).

Also, buy a couple of these:

some sainted guy in this very group recommended these a few years ago: it's like wearing your own radiator: "fantastic bit of kit"!

John

[Another John]

Sorry - protocol faux pas: that's a link to Matalan's padded work-shirts!

J.

[Grimly Curmudgeon]

[Dave Liquorice]

Really need to do it over several days, say a week then average it. This place consumes far more energy when it's cold and windy compared to cold and still. You may also pick a day of bright sunshine and even at this time of year solar gain is significant.

Even assuming the 800W electric heater has no thermostat and is on for all of the 11 hours that's 8.8kWhr. For the sake of simple maths if the boiler is 17.6kW that's only 30 mins of run time for the boiler or less than 3 minutes an hour. I find that level of boiler use unlikely, I'd expect 5 mins burn time just to heat the water in the rads to operating temperature...

Of course one has to take into account the cost differential per kwHr between gas and electricity. What's gas these days 5p/kWhr? Electricty can be had for less than 10p/kWHr.

My gut feeling is that the electric heater will be the cheaper option, particulary if it has a thermostat and isn't producing heat for all of those 11 hours. But the only sure way is to measure gas consumption over a number of days and do the maths.

[meow2222]

Electricity is 3x the cost of gas per heat output, so its cheaper to heat 1/15th of the house electrically.

NT

[Man at B&Q]

You also need to include the usage in the time it takes to reheat the house if the heating is off all day. It's a variation of the age old "leav it on all the time or let the house cool down and re-heat" question.

MBQ

[dennis]

I find it hard to see a variation when its always uses less energy to reheat than to keep it hot. The only way it isn't is if you can design a heater that wastes more energy when its being used with a bigger temprature difference.

[ARW]

It depends on the thermal mass of the building.

[The Other Mike]

You forget about the intermittent 'need' to heat the property to 3000 deg C when SWMBO comes in as she is cold. Compare this to a constant lower temperature and you can clearly see where the savings could be made.

Keep the thermostat at say 17 deg C, giver her a thermometer that over reads, and a dummy thermostat knob to twiddle and your heating costs can drop dramatically.

[robgraham]

[The Natural Philosopher]

the amount does, yes, but not the principle that running a house on average at a lower temperature, because sometimes its unheated, always results in less heat loss.

If the time constant of the house exceeds the period for which it is off, then its isn't going to cool much between heat bursts, and so you might as well heat it all the time.

[dennis]

8<

Ahh, I avoided this by fitting stats that she doesn't know how to change. At best she can override day and night.

[geoff]

We'd better come along and show her when you're out collecting trolleys then dense

[geoff]

During my first winter living in germany, the temperature got down to

-26C

That walk into work in the morning meant that it felt like needles were being fired into my legs

Thermal underwear I hear you shout

Yeah, fine until you get into work where the offices are kept at a toasty lower 20s C

You sweat your cobs off

moral of the story - wear something like ski over trousers that you can actually take off so you feel comfortable in both environments

[Dave Liquorice]

Didn't that work place have toilets?