Underfloor system - Electricity Bill

[tsutton]

Hi all,

I am hoping you can help me with something that I am battling with…

We have an extension with underfloor heating system, controlled by a Heatmiser Neo – neoHub with 2 x neoStat V2 Programmable Thermostat. (one for wet room and one for living area)

This has worked well for about a year until very recently when my father in law died, so we adjusted the heating to be lower than usual (he needed the heat a bit higher doe to his conditions) as the room wasn't in use very much.

But ever since then, we have noticed that our electricity bill is much higher since we made the changes.

During the time he lived there, the average temp was set to about 23C with about 19c to 20c overnight (depending on weather) before kicking back to 23c by 6am.

We changed it to 19c during the daytime with 16c overnight. That’s where the electricity bill has gone up since then.

My question is… why? I would have thought that by setting it to lower temperature, we would be saving electricity. But it’s the other way round?

Is it because it takes longer to heat up if the overnight temp is set to 16c? Or do we have a faulty system somewhere?

Thanks all.

 

[stem]

I would have thought that by setting it to lower temperature, we would be saving electricity.

Assuming that your UFH is powered by electricity and not wet, that would be correct reasoning. Put less energy into something then and you would expect the cost should be correspondingly less. A similar scenario would be: I used to drive 100 miles a week in my car, now I only drive 80 miles a week but my fuel cost has gone up.

When you say that the "bill has gone up" I assume that you are referring to the price. Ideally you should be comparing the actual kWh used and not the cost. Is it possible that you are actually using less kWh, but the unit cost has risen because a fixed price tariff has ended?

Also, are you considering the same periods of time when making your comparisons? heating a room to 23 degrees when it's 13 degrees outside, would use far less energy that when it was 3 degrees outside.

Electricity usage will not just be for the UFH. Has anything else changed. For example due to all of the wet weather have you been using a clothes dryer more frequently than before? Have you changed a gas cooker or oven for an electric one? Purchased an electric vehicle? Have you started growing cannabis in the loft?

A friend of mine once complained about his electricity bill increasing dramatically and said nothing had changed, yet on investigation his wife had started using an electric kiln in the garage to fire home made pottery on a regular basis, when previously it had been just an occasional hobby.

 

[tsutton]

Thanks for the reply, stem. Yes, the UFH is electricity and not liquid.

Our electricity tariff does not end until May 2020, which means we're still on the fixed terms, so it's not that. I will review the kWh and compare with the month before, see if anything has changed.

Our ways of using the washing machine, tumble dryer and dishwasher has not increased, however is less than last year. We have not added anything new to the house. Our cooker is still electric as before, no new electric vehicle and 100% very sure we're not growing cannabis in the loft.

We have done the power off of some high usage equipment and watching the electricity meter disc spinning slowing down. The only time the disc spinning that went faster than usual was when we switched on the UFH and that's where I am basing my findings on that.

So, based on your reply, it is sounding like when I set the overnight temp too low, it would have to use up more energy to achieve the target temperature, and even longer if the weather is colder outside?

Maybe I should adjust it back to how it were before my father in law died so it can stay at reasonable temperature without dropping down too far down? This way, it would use less energy to reach the target if my thinking are correct...

 

[JohnD]

Do you have night storage heaters and cheap off-peak electricity?

Owners of electric UFH often turn it off and burn bundles of five-pound-notes instead.

 

[tsutton]

No to both of your questions.

 

[big-all]

just a though
do you also have gas central heating that could be directly or indirectly adding to the heating off the room if so has that level off heating been turned down ??

 

[tsutton]

The door is always shut most of the time, so each heatings are not affected with each other. The extension do not have any radiators at all, so our gas boiler in the main house do not cover extension.

 

[big-all]

was it mostly open before ??
at about 30% the cost off electric leaked heat from the house would reduce the electric bill

 

[tsutton]

No, it has always remained shut.

 

[big-all]

take a kwh reading turn the heating off for a couple off days and see what happens?

 

[tsutton]

Yes, that's my next plan of action - thank you.