Gas on constantly or on and off...?

inaminute23

davecon1 wrote: »

This discussion seems endless but I've been trying to work out the most cost and fuel efficient to heat my house.

We're in a 4 bedroom end of terrace house with no cavity wall insulation and rubbish double glazing (very thin). The thermostat is set to 18 C and all the rooms have programmable thermostatic valves which are set low.

So far the heating is set to come on at 7.10am-8.30am and from 7.10pm-10.30pm. During the cold spell I've been checking my gas meter (cubic feet) and typically use 3 units over a 24 hour period and since Nov 21st we have used around £55 gas according to the smart meter site.

Now here is the interesting bit. Recently I have been working from home and have had to resort to having the heating on all day (thermostat still on 18 C). As I'm downstairs most of the time the rads upstairs are off (no sense in heating an empty room) BUT my gas consumption has been exactly the same for 12+ hours as it was for 5 hours. The outside temperature has been more of less the same each day (around 1C during the day and -1C at night).

Without being called a simpleton etc can someone please explain how this can be possible? I do understand that leaving your heating on all day should in theory massively push up your bills (vs leaving it on timed while you are out) BUT my recent tests seem to show that this is not the case as I was expecting my usage to almost double!

Any advice or comments?

Oh dear Cardew Are you going to tell this person he is"talking rubbish" or are you going finally concede that in these circumstances it is no dearer to leave it on stat 24/7? I expect you will spout s*ite by saying " well the laws of physics say it has to be on a timer, blah, blah, blah

The only explanation i can give is that when ther boiler is off over night the temp drops that much, so when it does come on it is working it's balls off to get back upto 18 deg.

HappyMJ

It depend on the outside temperature. On a cool day I'll use 10kwh and on the really freezing days last week I've used 35kwh. Today is looking like a 15kwh day. Yesterday was a 22kwh day. That's heating on and set to 18 (I don't like it too warm-work from home) from 10am till midnight. The base usage with no heating is 3kwh all day so it's the outside temperature making the difference.

closed

Opening trv's up is not moneysaving advice, they are designed to save money, and maintain comfort. It doesn't take long to work out what is a comfortable temperature setting, without knowing the figure in Celsius (which is probably in the instructions if you really need to know)

However many people say it is cheaper to heat 24/7, it will never change the simple fact that the more you heat it, the more goes out of the windows, door, walls and roof, if you are out or asleep, that it wasted money. Identical comfort levels can be achieved with correct use of the timer, thermostats and TRV's, at a reduced cost.

Find a scientific report that claims it is cheaper to heat 24/7, and then people might take the idea seriously.

inaminute23

Right! I've turned my heating off (current temp in my lounge 20deg), set it to come on 6-7am. My stat is set at 19. So i'm going to predict that it in the morning it will burn gas for the whole hour and the temp in my living room will get to 17, and not 19. I will let you know tommorow, and no doubt revert back to sticking it back on 24/7 with the stat set at 19.

inaminute23

closed wrote: »

Opening trv's up is not moneysaving advice.

Installing a stat is though. Why do some people on here only pick out quotes to suit them?

inaminute23

Cardew wrote: »

You are really referring to condensing boilers here, and this myth has been around long before those were invented.

The same as the oft quoted example of a kettle. If it is cheaper to have it at a constant temperature, why don't we leave the kettle simmering all day; rather than let it go cold and have to heat it up.

Laws of physics - you can't simmer a standard household kettle all day with out topping it up. Also these are mainly electric, and we are talking gas. However if you insulated your kettle it would boil quicker.

closed

A stat measure temp in one room, a trv measures in every room. I have both.

If it doesn't get to your desired temp in the morning, it needs to be on longer, but it doesn't need to be on all night. If you are going out, does 2 degrees matter?

JasX

inaminute23 wrote: »

Right! I've turned my heating off (current temp in my lounge 20deg), set it to come on 6-7am. My stat is set at 19. So i'm going to predict that it in the morning it will burn gas for the whole hour and the temp in my living room will get to 17, and not 19. I will let you know tommorow, and no doubt revert back to sticking it back on 24/7 with the stat set at 19.

cool, lets make this a fair test:

check outside temperature (needs to be roughly the same for both 24 hr periods, we can repeat as necessary)

Note your meter reading at the start, setpoint will be set at 19deg throughout, no hotter, no colder

Test 1 - leave your heating on all day

Test 2 - time your heating with all other variables equal to only come on for a few hours in the morning and a few hours in the evening according to comfort (but for the SAME set temperature.

Noting meter readings at the start and end of every 24hr period and if anything else changed -then we'll see what is cheaper.

inaminute23

JasX wrote: »

cool, lets make this a fair test:

check outside temperature (needs to be roughly the same for both 24 hr periods, we can repeat as necessary)

Note your meter reading at the start, setpoint will be set at 19deg throughout, no hotter, no colder

Test 1 - leave your heating on all day

Test 2 - time your heating with all other variables equal to only come on for a few hours in the morning and a few hours in the evening according to comfort (but for the SAME set temperature.

Noting meter readings at the start and end of every 24hr period and if anything else changed -then we'll see what is cheaper.

Ok no problem!

meter reading at present is 9291.9

outside temp is minus 6 (same as last night)

stat set at 19 deg

current temp 20 deg - not changed since 7pm (heating been on stat all day)

2 days ago at 7pm my gas reading was 9285.1 with the temp outside very similar. So 6.8 units over 2 days = 3.4 per day on similar temp outside

If i go on timer it will be 6-7am, and then 6.30 - 9.30pm

the other day the gas burnt for 30 minutes to raise the temp by just 1 degree (was experimenting), and used 0.8 of a unit approx 30kwh. That scared me!

inaminute23

closed wrote: »

A stat measure temp in one room, a trv measures in every room. I have both.

If it doesn't get to your desired temp in the morning, it needs to be on longer, but it doesn't need to be on all night. If you are going out, does 2 degrees matter?

There's my point if you put it on longer you use more gas. It is defo cheaper to heat my house to my desired temp 19 deg 24/7. Yes 2 deg. does matter.

The problem isn't in the morning as upstairs in the bedrooms is nice & toasty. I do not enter the living room in the morning, but at night i do untill about 11pm