Energy myth-busting: Is it cheaper to have heating on all day?

wantanswers

Seriously Cardew, some are convinced night set back save, some say as much as 6% other reports I read say not but don't dismiss them.

Have you got any opinion?

Cardew

wantanswers wrote: »

Cardew, obviously night set back is not new, some say it does save others not....

Any opinion?

Personally I shut off my Gas CH overnight and have it timed to come on 20 minutes or so before the first person gets up in the morning. I have my non-condensing boiler set to maximum(82C) and the house warms up very quickly.

A house and contents are a huge thermal store and overnight the temperature in the house doesn't drop a huge amount.

I have a indoor and outdoor monitor that records the highest and lowest temperature for both indoors and outdoors. I have just checked and the lowest outdoor temperature in the last week or so was minus 2.3C and the lowest indoor temperature was 15.1C.

Even the exceptionally cold winter of two years ago didn't require a change in that routine.

How people run their heating is completely their own business, and house characteristics vary. However in my case 'setting back' the temperature to 15C over the last week or so would have been no different to shutting off the heating.

It never ceases to amaze me that whenever the 'annual' Constant v Timed debate comes up on MSE the discussion moves away from the central issue..

That issue is which method is cheaper -

A. Leaving a house set at a constant temperature 24/7,

or

B. Having the heating timed, so it is off some of the time and when on the heating rises to the same temperature as 'A'.

Now in spite of what some people say, no matter what experiments they have carried out, regardless of what the gas fitter down the pub says, the answer is ALWAYS that method 'B' will be cheaper.

Lowering the temperature(setting back) for periods(e.g. overnight) instead of switching off is just a variation of method B and will also be cheaper than method A.

wantanswers

Cheers for that Cardew, ultimately its down to the owner to adopt whatever is best for them.

The problem I have when outside temperatures like lately are below zero and I have the heating timed similar to yourself, what I find is that the warm up time, hence furnace running time, because the rooms have dropped to around 15 -16C, it takes quite a time and uses excessive cu mt gas to reach 20C ( probably because of the mass). After reaching temperature the system ticks along nicely.

For me by experimenting with set back and a little inexpensive boost in the morning I am appearing to make savings (cutting the long start up furnace running). Time will tell of course but it appears to be the way forward for me and if it is successful i will probably invest in a inexpensive set back controller and also adopt a routine.

Cheers.

bestyman

I own a 100 bedroom hotel, but I only have a booking for one room next week. The guest will arrive at 8pm and leave at 8 am on Monday night.
Am I better off
1. Heating all 100 bedrooms constantly for 24 hours a day 7 days a week?
2. Just heating the occupied rooms, as and when required?

Atidi

bestyman wrote: »

I own a 100 bedroom hotel, but I only have a booking for one room next week. The guest will arrive at 8pm and leave at 8 am on Monday night.
Am I better off
1. Heating all 100 bedrooms constantly for 24 hours a day 7 days a week?
2. Just heating the occupied rooms, as and when required?

Neither.

You'd be best off re-booking the guest into the nearest top hotel at your expense, and selling the dump of a business you are running (or rather failing to run) before the receivers are appointed.

grahamc2003

bestyman wrote: »

I own a 100 bedroom hotel, but I only have a booking for one room next week. The guest will arrive at 8pm and leave at 8 am on Monday night.
Am I better off
1. Heating all 100 bedrooms constantly for 24 hours a day 7 days a week?
2. Just heating the occupied rooms, as and when required?

I'm afraid we need much more information.

Is the thermal mass of the bedrooms quite high or quite low? I don't really know what a thermal mass is, but I know it's very important.

Does the hotel exits where Newtonian classical physics applies (i.e. in our Universe and dimension, or is it in another Universe and or in fifteen dimensional space-time)?

If the heating is turned off, do you supply umbrellas for the guests to guard against the danger is rain formation inside the room?

Are your guests psychic in the sense of knowing whether the heating has previously been turned on and off or on constantly? If they are, do they, for inexplicable reasons, find 23C comfortable when the heating has been set on and off, and yet find 20C comfortable when it has been constantly on?

Are any of the guests likely to spontaneously run around the hotel setting every thermostat up several degrees if the previous night the thermostat turned the heating off while they slept?

Do any of your guests ever go to the pub, so they can get a definitive answer from a plumber they may meet there?

Empirical evidence from research at the Open University indicates houses with heating off warm up much quicker than when heating is turned on. Perhaps there needs more research to see if this happens in hotels?.

Are there telivisions in the rooms? If left on standby, they could use up to 1W, thus heating the hotel for free

I suggest you run a test. If you want the answer to be that it's cheaper to be on permanently, then set the thermostat to 5C for that test. The next day, hopefully in colder weather) turn the thermosat up to 30c for the intermittent test. Use an Owl for accurate results. If you miss a critical reading, simply make one up.

Do not let the fabric of the house cool, but turn the heating off at night. If the heating is turned off for 6 hours manually, the fabric cools, but if it is turned off by setting the thermostat very low for 6 hours, the fabric doesn't cool.

Heat losses from hotels depend on how comfortable the guests feel. If they feel uncomfortable, the heat loss can rise significantly, therefore to minimise heat loss, keep the hotel at 23C.

Do you have wood burning stove in the rooms? If you do, then you can light them, and ignore the heat they give out when deciding whether it's better to keep the boiler on 24/7.

I hope that summary from MSE helps you in this very complex decision.

wantanswers

grahamc2003 wrote: »

Are there telivisions in the rooms? If left on standby, they could use up to 1W, thus heating the hotel for free

That's a goodun Graham, how do you work that one out?

wantanswers

I've got a bag of freezing peas strapped to my back at the moment, will i need to compensate for loss of temperature?

grahamc2003

wantanswers wrote: »

I've got a bag of freezing peas strapped to my back at the moment, will i need to compensate for loss of temperature?

I'm not really sure of your question. But anyhow, I think I'd advise jumping into an extremely hot bath, and making a seasonal yet funky turkey and pea soup.

FatherAbraham

Try timing it so you put your washing out on a clothes horse during the hours your heating comes on. Normally, that way you wouldn't use any more energy.

This is rotten advice, once one takes into account the cost of dealing with the extra humidity produced in the living areas of the house. Indeed, the more airtight your house (which modern houses are designed to be, in order to achieve high energy efficiency), the worse the condensation problems will be.

Even worse, it's only about a month ago that news media warned about the health risks (mostly respiratory) of drying wet clothing in living areas: http://www.bbc.co.uk/news/uk-scotland-20176376

Finally, as has already been noted above, by WestonDave, the drying process will sap energy out of the air as the liquid evaporates, meaning that the heating system has to work harder to warm the air up again.

Three good reasons not to do as suggested.

I'm surprised not to see "try to dry outdoors as much as possible -- even if the temperature is freezing, some moisture can still be wind-blown out of hanging clothes".

Another would be "wear fewer cotton clothes, since the natural fibre, which absorbs moisture, is immensely expensive to dry". Artificial fibres, modern polyester, and micro-fibre-based clothes dry in a quarter of the time, whilst performing well in adverse conditions.