High gas bills - possible meter issue?

molerat

Heating a natural fridge is not going to come cheap.



That said, my max use this winter has been 10 cu m for a 1980s 3 bed detached in N Scotland with an antique boiler, 11 house rads keeping the rooms at 18 - 20 24/7, heating the conservatory to 9 (which is quite a lot of the time Nov - Feb) and as much hot water as I can use.

thorganby

duggsy69 wrote: »

Haha, apologies guys and girls, manic few days and also wanting to fully test everything and give you the full information. Hopefully, some clever person amongst you can do some maths and work out if our readings are right. He we go:


Boiler is a Vaillant ThermoCompact, rated at 26.7kW and tested to be running at 27.1kW
Tank is MegaFlo Efficiency Heatrae Sadia - 125 L
Gas meter is a mechanical meter, measured in cubic metres - Khrom Schroder BK-G4


We have tested the hot water ONLY for three days, running for 2.5 hours per day and being used for 2 showers (which typically empty the tank) and a bit of washing up, as well as gas hob cooking (oven is electric). We used an average of 1.75 cubic metres/day.


We then tested heating and hot water, with hot water running as above and heating running for 4.5 hours and serving 7 radiators with local thermostatic controllers (some set to full, others not) and we used 5.2 cubic metres. We have NO thermostat in the flat, only local radiator stats.



First question, are the above figures reasonable with the information given?


Second question, for January and February, our usage was averaging 10 cubic metres per day and during that time we had barely any heating because the system just wasn't working, we will have had it on for longer hours, perhaps 6 hours per day. If the radiators were struggling to reach temperature during that time, would the system just keep firing as it tried to get them hot?


To repeat the initial query, our bill from Jan 1st to date is around £800 for gas and electric for a one bed apartment. In our previous, larger, two bed apartment it was £400 for the year, and in another one bed apartment it worked out about £550 for the year. You can probably undertand why we're so amazed that we've hit £800 just five months in.


Thanks for your thoughts and advice, really is hugely appreciated.

You asked "are the above figures reasonable with the information given?"


Yes they are but you live in an old Georgian property with a crap heating system!

You obviously don't accept what you have been told, so if you are so sure that the meter is faulty then put your money where your mouth is and do as Houbara suggests, get the meter tested.

However you have effectively already done that with your hot water only testing over three days.

If the heating was not working properly during Jan - Feb the 10 cu M usage is irrelevant because the boiler would have been working hard trying to heat the rads, however you have used the gas so you obviously have to pay for it.

If you can't afford the bills for this property, you can always move.

dunstonh

Yes, no thermostat seems pretty mad, but that's the way it is.

It doesnt have to be. Many legacy systems can have a modern thermostat added. It probably wouldnt be that expensive either.
Without it, you are effectively running the boiler on constant during the timed period.

Talldave

Ok, so I dug out my spreadsheet from a 2 bed flat. Water heating when it had an Ideal boiler with tank used 1 cu m a day. That was for 80l or 120l, sorry don't know which size was fitted. I suspect the 2.5 cu m is probably realistic based on the larger tank and the fact that you said it's ludicrously hot (you're wasting gas to get it too hot).

So the first step is to reduce the setting on the tank thermostat. Also, if the valve(s) controlling the heater/hot water flow is/are faulty, some of the heat intended for the hot water tank could be pointlessly flowing around the heating circuit. When the hot water is being heated, you could check that none of the heating pipes near the valve(s) get hot - the hot water from the boiler should only be going around the loop to the tank.

I think a faulty meter is unlikely, the system is just crap. I suggest getting the hot water checked first (lower temp and confirm no flow around heating/radiators) before working out what to do about the heating. This is the best time of year to get the heating fixed, so come Sept/Oct it's working better.

Interested to know what the controller is for heating/hot water.

nigelbb

dunstonh wrote: »

It doesnt have to be. Many legacy systems can have a modern thermostat added. It probably wouldnt be that expensive either.
Without it, you are effectively running the boiler on constant during the timed period.

Apparently all the radiators have TRVs so another thermostat would be redundant.

thorganby

nigelbb wrote: »

The OP hasn't bothered to return with any information so all the other suggestions about meter checks etc are pretty redundant.

Yet you have returned with a totally incorrect post which shows why you definitely should not have bothered!

Why post about something that you obviously do not understand.

nigelbb wrote: »

Apparently all the radiators have TRVs so another thermostat would be redundant.

Talldave

nigelbb wrote: »

Apparently all the radiators have TRVs so another thermostat would be redundant.

So where would the "call for heat" come from? You need a room thermostat somewhere to tell the boiler to come on in the first place. The TRVs simply let you set some radiators to shut off at a lower temperature. I'm not a heating expert but I think you need one radiator without a TRV to prevent a lockout where all radiators are set low and the boiler's running to try to achieve the room thermostat temp.

The room thermostat is in series with the timer that determines whether it's the time of day you asked for the heating to be on or not. Of course you can combine those two functions into a programmable thermostat but if there's already a two channel timer for heating and hot water you then have to set the heating permanently on at the timer and use the timer on the programmable thermostat.

As another poster has already stated, without a room thermostat the boiler will be permanently on for the entire time the timer has the heating set to on. That's insane.

In the OP's case, the room thermostat probably needs to be in the coldest room and the TRVs on all other radiators will shut them off once those areas are warm, leaving all the heat flowing to the cold room. If it's still a struggle to heat that room (assuming the radiator is scalding hot and there's not a flow problem), it may be worth increasing the size of the radiator in that room.

A wireless thermostat gives greatest flexibility but don't leave it in a room with the TRV set low otherwise you'll just be running the boiler permanently trying to achieve a temperature in that room that the TRV won't allow!

dunstonh

So where would the "call for heat" come from? You need a room thermostat somewhere to tell the boiler to come on in the first place. The TRVs simply let you set some radiators to shut off at a lower temperature. I'm not a heating expert but I think you need one radiator without a TRV to prevent a lockout where all radiators are set low and the boiler's running to try to achieve the room thermostat temp.

That is it.

We have TRVs on every single radiator. Not by choice or design but a legacy of previous owners and changing systems over the years.

We recently put TRVs on all the radiators without them as they were secondary rooms. So, this put us in the same position as the OP of having TRVs in every room. The room with the thermostat has the TRVs turned up to max. This means the TRVs are not being used in that room. However, the room thermostat controls it. Our room thermostat is in the kitchen. Normally not an ideal place for it but our property layout and the size of the room makes it the best location (Kitchen is 33x17ft with most used exit door and two of the lounges have woodburners in, as does the hallway and one has underfloor heating on a different system - just to avoid anyone saying that having it in the kitchen is a bad idea - Yes, hallway is often best but not in our scenario)

If you don't have a room thermostat and are at a stage when all the TRVs were turning the radiators “off”, but the timer and the boiler thermostat tell the boiler that heat is still required, the boiler will keep firing-up but not delivering any further heat to the radiators. The system will just be burning gas for no reason.

You dont need to remove any TRVs if you get a room thermostat (wireless is best). just turn up the TRVs in that room to max.

grumpycrab

duggsy69 wrote: »

using 10 units [gas] a day average in Jan/Feb and now, with only hot water on for an hour a twice a day, are using 2.5 per day

Just going back a step (sorry if already covered) that's no more than £400 by my calculation. (835 units = 9240 kWh). So that's £400 of electricity in 5 months too?

Uxb1

I've had TRV's on all radiators since day 1
that's about 30 years.
There is no room thermostat
The boiler comes on an off depending on its own internal thermostat - provided of course the timer is on.
If all the TVR's went off (which actually will never happen) then the pump would pump water round the bypass loop which would open the bypass valve and the boiler would see return water at the same temperature as the outgoing water and switch off.
Indeed the boiler cycles on and off regularly when in use as the return water temperature varies depending on how much heat is lost round the system pipes and radiators - if heat is not required then the pump continues to pump the water round the system with no extra heat from the boiler applied.