February 25th 2007, Our House, Derby
We spent a bit of time digging around on the internet and other places trying to find out how we could make improvements to our central heating.
Most the information is basically variations of the same thing i.e. improve insulation, get a more efficient boiler etc. Some changes we have made now, other we will make in the future.
Immediate Changes
These are all small things that didn’t take too long to sort out but we think will help straight away.
Boiler
The boiler has its own thermostat but it has no effect on the temperature of the heating or hot water. Instead it determines how fast the boiler heats up, think of it like a car accelerator. Ours is set to Max so the house heats up as quickly as possible.
Radiators
Preventing Heat Loss
All radiators transfer heat into the wall they are attached to. This isn’t a problem on interior walls as the heat remains in the house, but on outside walls the heat goes through and then out and is lost forever.
We got special silver radiator foil to go behind the 2 radiators that are on an outside wall to reflect this heat back into the house.
Problem is the foil looks crap, so we have painted it to blend in with the wall its on.
If anyone knows if this reduces there reflective effectiveness can you please let me know.
Bled Them
If air gets inside the heating system it stops the radiators from working properly. The trapped air prevents the hot water filling the radiator making it cold to the touch at the top.
We bled the radiators to make sure all the air was out of the system.
Hot Water Tank
Our tank has a bare metal plate, where the immersion heater would go, that isn't covered by the factory fitted foam insulation. Heat just seems to pour out from it, certainly enough to keep the airing cupboard warm.
To prevent this we fitted an extra 80mm thick jacket on top of the factory insulation, to make sure every last drop of heat stays in the tank. It must be working as the cupboard is no where near as warm as before.
Timer
No
changes were planned to the timer itself, however we will be a bit smarter when
it comes to our days off and holidays.
Normally we would leave the timer and just let it come on at the same time as if we were working, but as we tend to get up much later when we aren't that's clearly wasting energy. Now we will change the on time to something more appropriate when we are off.
The time the heating goes off in the evening has also been brought forward. It now goes off 45 minutes before we would normally go to bed. Our house does seem fairly well insulated as it stays comfortable for quite a while once the heating is off.
Also the original timer went bang leaving us with no hot water or heating. Its now been replaced by a new British Gas UP2 timer, with 3 On/Off periods per day rather than the 2 the Potterton had.
Room Thermostat
Digging around it seems that mechanical thermostats are widely considered inaccurate and for every 1°C over the target temp, you use up to 10% more energy. When the heating is off they are slow to respond and the temperature can fall between 3-5°C before the heating comes back on.
Digital thermostats are far more accurate, usually to a fraction of a °C. Rooms will therefore rarely exceed the target temperature so energy usage is minimised. Greater accuracy also means the heating comes back on as soon as the temperature falls maintaining a much more stable temperature.
Our original Potterton thermostat has been replaced by a
Sunvic TLX 7501 digital
room thermostat.
It wasn’t hard to change, 3 wires just like a plug, and is set to 21°C.
It does seem to work as the house now maintains a much more even temperature than before.
Thermostatic Radiator Valves (TRV)
Cleaned Them
We cleaned all TRVs by vacuuming them. We think this helps improve the accuracy of the temp sensor as its not full of dust and other crap.
Set Them
Having done the above we spent a bit of time finding out what temperatures the settings on each TRV gave us for that particular room. You cant just set them all to 3 and expect each room to be the same temp cos it all depends on the size of the room and the radiator.
We did this by adjusting the TRVs in each room till we got the temp we wanted, it took a bit of time to get in right though!
We set the Temps to the following.
|
Room |
Temp |
TRV Setting |
|
Hall |
21°C |
N.A. (Determined by Room Thermostat) |
|
Front Room |
21°C |
Radiator on exterior wall 3.25
Radiator on interior wall 2.75 |
|
Dining Room |
21°C |
1.25 |
|
Downstairs loo |
18°C |
1.75 |
|
Kitchen |
21°C |
N.A. (Determined by combination of heat from cooking and boiler) |
|
Bathroom |
21°C |
3.75 |
|
Our Bedroom |
20°C |
2.25 |
|
Leah's Bedroom |
20°C |
4 |
|
Spare Bedroom |
18°C |
2.25 |
|
Conservatory |
20°C |
1.5 (Determined by thermostat on Convector Heater) |
We also made the decision that once the radiators were set we wouldn’t change them just cos we felt “a bit cold”
Instead, knowing that the heating is set to how we want it, if we did feel a bit cold (and sometimes you just do) we would take that as the cue to move around a bit more or put some more clothes on.
Hot Water Thermostat
Should be set to the maximum temperature you actually need rather than having it too high then having to add cold water to use it.
In our house the dishwasher needs the hottest water, at 55°C. However the dishwasher doesn’t use the hot water supply, instead heating cold water internally.
The next hottest water requirement is the washing machine. We now do all our washing at 40°C, its only vary rarely we use a 60°C wash.
So we decided to set the hot water thermometer to 50°C (To allow for some inaccuracy) using the logic that surely its better to let the washer heat the water to 60°C on the rare occasions its required, rather than maintaining an entire tank full at 60°C.
Other Bits
Several pipes in the airing cupboard that fed the central heating system were not lagged. They are now.
We also picked up a great little tip for cooking pasta and saving gas at the same time. You boil the pasta for 2 minutes, then turn off the heat and cover the saucepan. Leave it for the full time indicated on the packet, just giving it an occasional stir. At the end of this you will have perfect pasta and saved energy.
And yes before anyone points it out, we know the cooker isn't part of the central heating system but it does use gas so we are going to put it here!!
How can we tell if these changes work?
Our immediate impression is that the temperatures throughout the house seem much more constant, and therefore comfortable, despite the fact that the Room Thermostat and all the TRVs are set much lower than they were before.
The boiler doesn't seem to be on as much, and no one even noticed that Kev had reduced the Hot Water Thermostat setting.
However all we can really do is compare the amount of gas we used last year to the amount of gas we used since these changes have been made. Not perfect we know as some of that will depend on how cold or hot its been outside.
Total usage for year prior to changes was 12000kwh, enough to generate 2280kgs of CO2. We will monitor the same periods this year to see what happens.
What else we plan to do?
-
Look at ways to off set the CO2 produced by our cars.
-
Look at ways to reduce our gas consumption.
-
Look at ways to reduce our electricity consumption.
-
Look at ways to reduce our water consumption.
-
Work out what our Carbon Footprint is after we have done the above.
-
Find out how to recycle more and monitor just how much we do.