What ideas have you had for reducing Electricity consumption

[Oldman]

I was wee concerned that our 15+ year old fridge freezer might not be running efficiently and was looking for a reason to replace it! So I bought a smart plug to monitor energy consumption and this was the outcome:

week 1= 19.4 kWh
week 2=16.5 kWh after having used my air compressor to blow out the dust at the back. This is something I now do annually after it suddenly gave up the ghost 5 years ago and a few days b4 Xmas!!! Somehow this seemed to get it going again and so far so good..........
week 3=14.8 kWh
week 4=12 kWh after having turned the freezer down to -18c
week 5= 11kWh

I wouldn't expect it to fall any further and I reckon it dropped to 11kWh because I was home alone all week.

I have satisfied my curiosity and it just goes to show how much energy was being wasted. My smart plug will now be used for the purpose for which I bought it which is to turn the heater on in my office outside early in the mornings.

I have a pass through checker and recently monitored the wattage used over 48hrs on out 2 fridge freezers and a garage chest freezer.
Of the 2 fridges (frost free) one used around 950watts/24hr with the manufacturer saying 284KW/yr
The other one used 750watts/24hr with the manufacturer saying 311KW/yr
The chest freezer was 550watts/24hr with 221KW/yr
All of mine are less than 8yrs old and your figures if correct you may want to consider replacing it with the rising cost of electricity.
Link to the type of checker I used. Energenie ENER007 Energy Saving Power Meter Socket

 

[houtslager]

When my next door neighbour make the early cup of tea in the morning he puts the remaining hot water in a flask for thr mid-morning coffee. Also,you could use the remaining water for washing up.

Being doing similar for yonks, ever since I was in the Army. Any time we boiled up any excess water was put in a flask, or norgies and when doing lots of water into s/s inserts of the hayboxes we used.

 

[rs6mra]

I have a pass through checker and recently monitored the wattage used over 48hrs on out 2 fridge freezers and a garage chest freezer.
Of the 2 fridges (frost free) one used around 950watts/24hr with the manufacturer saying 284KW/yr
The other one used 750watts/24hr with the manufacturer saying 311KW/yr
The chest freezer was 550watts/24hr with 221KW/yr
All of mine are less than 8yrs old and your figures if correct you may want to consider replacing it with the rising cost of electricity.
Link to the type of checker I used. Energenie ENER007 Energy Saving Power Meter Socket

I might look into it at some point but I'm kool with the outcome for now as a fridge freezer is according to the stats expected to use up between 1-2 kWh per day
I decided to monitor mine weekly and the weekly stats included when we were entertaining so both the fridge and freezer were being opened and closed countlessly. Our day to day lives differ quite a bit in our household so I had to look at it on a weekly basis.

 

[Sideways]

Got a new glass body kettle with fill markings printed on the side. These are far easier to use than the old one. I can now measure the water well enough that there's only 1/8" spare in the bottom of the kettle after warming and then filling the teapot

 

[Spectric]

Our next kettle will have a thermostat because you don't need boiling water, 90 to 98° C is better for black tea and this would save energy because the current kettle gets to 100° C but then continues to boil for 5 seconds until turning off. At 90 I would save a minute per boil so after 60 boils you save an hour.

 

[Fergie 307]

I bought an adjustable 7 day timer switch £30 ish had my lecy fit it to the feed of to the combi boiler turn boiler off each evening at 8 and on at 7 next morning object no hunting through the night. Might have to change the off to later when the winter comes.

Not sure if that is such a good idea. Some don't like being turned off by cutting the mains, certainly not on a regular basis, can damage the PCB. I'd be willing to bet the manual tells you to turn the boiler off at its own switch, before turning off at source. If you damage the PCB that's typically 2-300 quid, just for the board. Most also do a start up sequence when you turn the power back on, which involves a quite lengthy burn. So you might actually use more gas doing this. If it hasn't got a built in programmer, then most manufacturers do one specifically for their units, which is any easy retro fit. Then you can have it come on and off whenever you like.

 

[Spectric]

You would not do this to a system boiler because they have a pump overun timer so when the demand stops the pump continues to run to prevent kettling and dissipate the heat in the heat exchanger by moving the water round via the recirc line / bypass. If you just killed the power and there had been a demand then the heat exchanger is full of hot water with nowhere to go and this is not good for the modern lightweight boilers, no problem apart from noise with the big old cast iron jobs.

The point about

can damage the PCB

When you power up the boiler the software initialises and places the boiler into standby mode ready for operation, it has performed pre checks and gathered required data so it is just waiting for the demand signal. With a switch turning of the supplythen it goes through this process more often for no reason.

 

[Fergie 307]

The kettling is a good point. Not sure why the boiler should be hunting overnight, or what exactly the OP means by that. It will run periodically if necessary to maintain whatever temperature is set on the room thermostat. If you don't want it to do that then just turn the stat down, and turn it up again in the morning. If you fit the manufacturers programmer then you can use that to control when the boiler is active, and it will be designed to work in harmony with the boiler.

 

[Spectric]

Here is another thought, we are probably forced to turn on our heating earlier than otherwise needed because when you think about the radiators, they are just large areas of cold metal that must remove heat from a room so in effect actually reducing the temperature below what it would otherwise be. So what the system should do as a minimum is when the heating is off but the room temperature falls below 15° C would be to maintain the water temperature at the same temperature to prevent heat transfer. To prove the point I have been running the heating at 15° C during the day and the house feels warmer than with no heating yet it stated 15° C.

 

[Jacob]

Here is another thought, we are probably forced to turn on our heating earlier than otherwise needed because when you think about the radiators, they are just large areas of cold metal that must remove heat from a room so in effect actually reducing the temperature below what it would otherwise be. So what the system should do as a minimum is when the heating is off but the room temperature falls below 15° C would be to maintain the water temperature at the same temperature to prevent heat transfer. To prove the point I have been running the heating at 15° C during the day and the house feels warmer than with no heating yet it stated 15° C.

er - surely the radiator can only cool to room temp and no lower?
When you switch it on cold water will flow though at first, but it's circulating and any heat picked up will come around again.

 

[Terry - Somerset]

Strangely I find myself agreeing with Jacob on this one. If the radiators are at room temperature and no water is circulating, there can be no transfer of energy outside the room.

What the radiator full of water does do is increase the thermal mass of the room and make the air temperature somewhat less responsive to changes in external temperature inputs - eg: sunlight on windows, frosty evenings etc.

 

[Spectric]

If the radiators are at room temperature and no water is circulating, there can be no transfer of energy outside the room.

My initial thoughts, but with water having the greater density then there is no energy leaving the room but the mass of water in a radiator can absorb a lot of heat from the air and so in achieving equilibrium the room loses more temperature. On the other hand if there was no radiator in the room then the air would warm up more from external influences such as the sun as there is not heat soak in the form of a radiator so by having just a warm radiator removes this as a heat loss.

 

[Jacob]

My initial thoughts, but with water having the greater density then there is no energy leaving the room but the mass of water in a radiator can absorb a lot of heat from the air

Not unless it is colder than the air in the room.

 

[johna.clements]

Here is another thought, we are probably forced to turn on our heating earlier than otherwise needed because when you think about the radiators, they are just large areas of cold metal that must remove heat from a room so in effect actually reducing the temperature below what it would otherwise be. So what the system should do as a minimum is when the heating is off but the room temperature falls below 15° C would be to maintain the water temperature at the same temperature to prevent heat transfer. To prove the point I have been running the heating at 15° C during the day and the house feels warmer than with no heating yet it stated 15° C.

The radiators are not cold they are just at around room temperature. Unless water is circulating from a colder place they will track room temperature in the same way as a solid internal partition.

The radiators feel cold because metal transfers heat quickly, what you want in a radiator. When you touch the metal at 15C more heat is transferred from your body than an oak table at 15C. So the radiator feels cold but it is no colder.

 

[Spectric]

I think the water without having been heated is colder than the room which is trying to warm up due to external heat, so the air will warm up faster with less energy but the cold radiator is holding it back if that makes sense.

 

[johna.clements]

My initial thoughts, but with water having the greater density then there is no energy leaving the room but the mass of water in a radiator can absorb a lot of heat from the air and so in achieving equilibrium the room loses more temperature. On the other hand if there was no radiator in the room then the air would warm up more from external influences such as the sun as there is not heat soak in the form of a radiator so by having just a warm radiator removes this as a heat loss.

The radiators will have thermal mass so will heat up slower than the air when it is warm and hold onto the heat for when you need it when it cools down. But I doubt it will have much significance when compared to the walls floor etc all added together.

There have been buildings designed with masonry walls that get heated by the sun during the day then give off the heat during the night. Your radiators are likely to work like this but in a very low positive way.

 

[Spectric]

So the radiator feels cold but it is no colder

But using a thermocouple to measure the radiator temperature shows it to be 14.5° C at 7 Am. The room reached 15.5 ° at 9.45 as it is in the sun but with the radiator still at 14.5° . Maybe given enough time then you will reach equilibrium but you do need a lot more energy to raise water by 1° than air.

 

[johna.clements]

But using a thermocouple to measure the radiator temperature shows it to be 14.5° C at 7 Am. The room reached 15.5 ° at 9.45 as it is in the sun but with the radiator still at 14.5° . Maybe given enough time then you will reach equilibrium but you do need a lot more energy to raise water by 1° than air.

What about the temperature of the brick wall behind the radiator. That will heat up slower than the air as well. And both will cool down slower so releasing heat in the evening.

 

[TominDales]

Here is another thought, we are probably forced to turn on our heating earlier than otherwise needed because when you think about the radiators, they are just large areas of cold metal that must remove heat from a room so in effect actually reducing the temperature below what it would otherwise be. So what the system should do as a minimum is when the heating is off but the room temperature falls below 15° C would be to maintain the water temperature at the same temperature to prevent heat transfer. To prove the point I have been running the heating at 15° C during the day and the house feels warmer than with no heating yet it stated 15° C.

Hi all, lots of comment arising on this topic. The physics isn't entirely intuitive, things can feel hotter or cooler but that is due to their ability to conduct heat from our hands, so a radiator feels colder than the soft furnishing do despite being at the same termperature.. However you still have to warm the radiator 9and house) up prior to feeling warm in the morning.

Its not just the radiator that has thermal mass, but all the contents of the house, especially the walls. Most people put the heating on 30 minutes before they get up in the morning. This is to allow all the thermal masses to warm up to get a roughly uniform temp 18c or 20c depending on the level of conform/affordable comfort they want. Its not just the radiator that has cooled overnight, but everything. Similarly at night the heating can go off early as the house will take time to cool down. If the house is very well insulated the the heat wont escape during the night and the heating can come on shortly before rise. This is essential if running a low temperature heating system such as a heat-pump. Many modern heating systems have an outside sensors to help automate the pre-warming time, but its not really necessary in the UK as the outside temperature rarely falls below zero. As Jacob rightly said it makes no difference what the radiator is made off it will be the same temp as the room after sitting in equilibrium for 8 hrs. Yes it will feel cold to touch but that is because the metal conducts heat away from our hands, which are at 34c and we notice the difference.

 

[TominDales]

Why would anyone insulate the rafters? The roof space should be ventilated so it would be pointless.

If using for work or storage you may want some heat up their. Needs ariing but not a huge draft. However best to insulate the loft space ie the floor if not in use for the reasons Phil says