Meter Reading

ZacharyJohn

@thorganby If I’ve understood you correctly then the programmer dictates not when the heating will be ON or OFF, but when the heating will be on its COMFORT or SETBACK temperature.

So, if I set Zone 1 to ON (the terminology used in the manual) between 8.00 and 21.00 and set the temperature in the bedroom on its thermostat to 25:
- at 10.00 the temperature should be 25 (COMFORT temp)
- at 21.30 the temperature should be 20 (SETBACK temp, 25 less 5)
- if I were to keep Zone 1 at ON constantly, the temperature should never drop below 25
- if I were to keep Zone 1 at OFF constantly, the temperature should never drop below 20

Are all these statements correct? At the moment all Zones are set to OFF and the heating only clicks on when I turn the thermostat to about 33 - is this implying the room temperature is 28? 

Reed_Richards

One thing I find a bit weird is that you need wiring between every room thermostat and the controller to make the COMFORT/SETBACK options work (according to what I read about this and it has to be true).  But in your house it looks a bit as if they have skimped on wiring by not giving your underfloor heating dedicated circuits.

I'm not clear if you own or rent your flat but it's looking increasingly as if you need a professional to check your underfloor heating to see if it is working properly.  It does not seem to be.    

matelodave

TBH what you've actually got compared with what we think you've got (or should have) might be two completely different things so, as R-R suggest above, it might be a good idea to get the electrical company who did the work to come in and check it over and tell you the best way to operate it.

It's not going to be cheap to run so ideally you need to understand how to operate it effectively before next winter's heating season starts.

It would also be a good idea to get a time switch on the hot water heater to get a bit more control (there's no advantage in keeping the tank up to temperature all day if you are out or all night if you are asleep). You could probably get away with heating the water tank for just a couple of hours a day if you are fairly careful with your hot water use and dont waste it.

Lastly make sure you get yourself on a decent tariff - if you are going to be using lots of leccy, make sure it's as cheap as you can get it. Get into the habit of reading the meter every single monthe, sending in the readings and checking your bills and statements every month so you can keep track (make sure you check even if you've got a smart meter - theres no guarantee that they are using the meter readings)

Reed_Richards

matelodave said:

it might be a good idea to get the electrical company who did the work to come in and check it over and tell you the best way to operate it.

Except that it looks that they may have bodged the job.  Perhaps an independent expert would be a better choice?  

matelodave

It's also worth a mention that underfloor heating systems can be very slow to heat up and react to temperature adjustments especially those that are buried in the floor slab. They act like storage heaters and so take a long time to heat the slab and then to cool down afterwards so you need to allow plenty of time to see how the temerature is affected after adjusting the thermostat (possibly 4 hours or more) Carpets and furniture covering the floor will also slow down their reaction time.

They do have the advantage that you can ususlly get away with lower thermostat settings beause the heat is evenly spread over the whole floor area and is less strified than that from radiators/ - try it out at 19-20 for a few days to see how you get on and because it's slow reacting you might find that it needs to come on (or turn up) an hour or two earlier and off (or set back) an hour or two earlier than with a radiator system.

Always start with a low temperature and then just adjust it by say 1 degree a day until you feel comfortable - don't get hung up about absolute temperature settings (they are seldon everso accurate). The lower the temp the less it'll cost to run.

thorganby

ZacharyJohn said:

@thorganby If I’ve understood you correctly then the programmer dictates not when the heating will be ON or OFF, but when the heating will be on its COMFORT or SETBACK temperature.

So, if I set Zone 1 to ON (the terminology used in the manual) between 8.00 and 21.00 and set the temperature in the bedroom on its thermostat to 25:
- at 10.00 the temperature should be 25 (COMFORT temp)
- at 21.30 the temperature should be 20 (SETBACK temp, 25 less 5)
- if I were to keep Zone 1 at ON constantly, the temperature should never drop below 25
- if I were to keep Zone 1 at OFF constantly, the temperature should never drop below 20

Are all these statements correct? At the moment all Zones are set to OFF and the heating only clicks on when I turn the thermostat to about 33 - is this implying the room temperature is 28? 

Difficult to say with any certainty from here. The first thing that you need to establish is when the programmer zone is ON, does ON mean COMFORT or SETBACK? as it could be wired either way. The programmer has a BOOST function, so logically you would expect this to BOOST the active heating time for that zone.

You do not have many variables, so it should be easy to establish if ON equates to COMFORT or SETBACK temperatures by simply testing one room on that zone. When you know exactly what the programmer does, you can try different times and temperatures to heat the various rooms how you require them but remember using single rate electric heating is the most expensive bar none but you do need to give it sufficient time to raise the temperature from the SETBACK temperature. Your stats are specifically for underfloor heating and the SETBACK temperature has been optimised for this. The red LED indicates when heating is ON.

I don't believe that you have a botched job or you need to engage a professional or independent expert to tell you how to use your heating when you can easily experiment yourself.

Depending on your hot water requirements, you could switch OFF one of the immersion heaters, i.e. the top one and fit a timeswitch on the other one. This would significantly reduce your consumption and cost.

  

ZacharyJohn

Thanks for the replies all.

I rent the flat so it's not a long term issue but I certainly need to get a firm grasp on this before winter. I've gotten in contact with the landlord for info on the electrics (underfloor heating and immersion heater) so hopefully more light will be shed on the situation.

I've only had the water heater on a couple of hours a day since the beginning of the week and that seems practical enough with a bit of tweaking in terms of when it actually goes on/off. Interestingly, since I've been keeping close track of the kWh, it seems the water heater is the significant source of energy consumption. I need to investigate further but I had the top immersion heater on between 8.00 and 10.30 today, and the kWh increased by 1. I had the bottom immersion heater on between 10.30 and 1.00 and the kWh increased by 5(!).

I didn't isolate the heaters completely so a few variables may be throwing these values off but the energy from the bottom heater still seems remarkably high (and I would have thought it'd be the top one that would use the most energy of the two).

@thorganby I think you're right about the COMFORT/SETBACK situation. When the programmer is ON the heating switched on when the thermostat was around 26, when the programmer was OFF the heating switched on when the thermostat was around 31.

I'll do some more digging on both underfloor and water heating fronts and post my findings...

Very appreciative of everyone's help so far.

Gerry1

ZacharyJohn said:

I didn't isolate the heaters completely so a few variables may be throwing these values off but the energy from the bottom heater still seems remarkably high (and I would have thought it'd be the top one that would use the most energy of the two).

The upper heater will give you only half a tank of hot water whereas the lower one will provide a full tank.  The upper one may also be set to a lower temperature and/or be of lower wattage.  It's only intended to give an emergency top up at expensive rates if you are on an E7 tariff and run out of hot water during the day.

Reed_Richards

ZacharyJohn said:

I've only had the water heater on a couple of hours a day since the beginning of the week and that seems practical enough with a bit of tweaking in terms of when it actually goes on/off. Interestingly, since I've been keeping close track of the kWh, it seems the water heater is the significant source of energy consumption. I need to investigate further but I had the top immersion heater on between 8.00 and 10.30 today, and the kWh increased by 1. I had the bottom immersion heater on between 10.30 and 1.00 and the kWh increased by 5(!).

Typically an immersion heater consumes 3 kW of power and so has a 16A fuse.  That is 3 kWh per hour when it is actually heating the water but it cuts-out when the set temperature is reached.  Under the cover you will find a little dial that sets the maximum temperature before the immersion heater cuts out.  @Gerry1 is correct but given that you are NOT on an E7 tariff then It may be slightly cheaper for you to just use the upper heater if that gives you sufficient hot water.  

matelodave

Looking at your tank, it's capacity is probably around 150 litres. It's got two immersion heaters, one at the bottom and one about 2/3rds up so the bottom heater will heat 150 litres and the top around 50 litres.

It takes roughly 3kwh to heat the top 50 litres from cold and 9 kwh to heat the whole tank. Assuming that the immersion heaters have 3kw elements thats approximately one hour and three hours respectively. Converted to money at 15p/kwh = 45p for 50 litres and £1.35 for a whole tank.

So it's worthwhile trying to be a bit frugal with you use of hot water, dont let it run down the sink when washing stuff (including you) - put the plug in or use a bowl. Use cold water where possible and dont spend ages in the shower or have deep baths (and not to many of them either. Fitting an Eco shower head or flow restrictor to the shower will also reduce your hot water consumption. Every time you run off half a gallon of cold water to get the hot tap hot you'll leave half a gallon of valuable hot water sitting in the pipework to get cold so try and reduce the number of short draw-offs just to rinse stuff.

Another interesting fact, is that a well insulated hotwater tank like yours filled with hot water will lose around 1.5-2kw of heat a day (abour 25p worth at 15p/kwh) even if you dont use any hot water.

However if you only heat the top thrird, say twice a day and use most of it up between heating cycles rather than keeping the whole tank hot all the time you have the opportunity to save around 20p/day or abou £75 a year. It doesn't sound a lot but it could be worth it. You wouldn't do it with an E7 set up but it could be worthwhile for you.