Damn that cold spell

[SteamyTea]

When it became obvious, 15 months ago, that we were all in for a significant hike in energy prices, I decided to set a target of using less energy.  I generally used about 4 MWh/year.  This is down from 11 MWh/year when I first moved into the house over 17 years ago.

The initial target was 3.5 MWh/year for this year.  Putin invading Ukraine caused a lot of uncertainty, and much bigger price hikes, at one stage EDF were sending out silly 'estimates', but they have since stabilised, and in my case, actually reduced from last quarters peak.

So I set myself a new target back in May of 3 MWh/year.

So how did I get on.

I missed the new target, but was under the old one.

This was mainly down to the cold weather that started in the third week of November and carried though to the third week of December, it was at least 5° below average, and sometimes 10°C lower.  The weather is never very cold here, just feels it goes below 9°C. Daily mean of 9°C is around the temperature I turn my heating on.

 

So this last year, I have used a total of 3237 kWh, with 474 kWh during the day and 2765 kWh during the night.

That was as read by my old CurrentCost Opti-Envi meter.

The actual meter showed that I had used a total of 3224 kWh, with 503 kWh during the day and 2721 kWh at night.

Pretty good agreement considering that the EDF window initially had an odd hour between 23:00 and 00:00 hours and then 01:00 to 07:00 sometimes, and then 00:00 to 00:800 at other times, which I cannot be bothered to adjust for.

 

I made three changes to the house this year.

• First change, I fixed the leaky back door.  I was expecting to have to buy a new one, but found that the warping was being caused by a dislodged threshold.  Took 2 minutes with a screwdriver to put it right.  Lesson here is to investigate rather than assume.

I still fancy a new door, a barn type would be nice, but just cannot justify the price, so may try and make one.

• Second change, at the end of May, was putting a timer of the top immersion heater on the E7 cylinder and pulling the fuse on the bottom element.  This saved around 1 kWh/day, (can see the step change in the chart).  It has made the quantity of DHW marginal, and I have been caught out a couple of times, but I can live with that, though others may not.  15 minutes of override sorts the problem for a shower, so not exactly dreadful. I intend to play about with the timings, maybe 1 day of lower heating element and then two days of higher heating element to reduce the chance of running out of DHW, but it will be a marginal saving for little benefit. Timer was under £20.

My water usage has stayed about the same at 140 lt/day, though I really need to lower this, but I like a bath and dislike a shower.

• Third change was to make some secondary glazing for all but 1 window (should really be 2 windows, but decided to live dangerously).  I did this with cheap planed timber, very cheap polystyrene sheet (cast acrylic would be better, but I like to experiment first) and some W profile draught excluding foam tape.  Cosy about a tenner a window.  So about £120 for that  This has made a difference to both the U-Value and the draughtiness.  Though not the prettiest of retrofits, but as I expect the polystyrene sheet to start to 'frost', I can make it much better next time.  As a side benefit, the house is a lot quieter as well.

 

In all, I have probably spend £200 on 'energy saving improvements' and have saved approximately 0.8 MWh/year, with my profile of 85% at the cheaper 15p, that is £100 saving (and the savings only started from end of May), so come next May, I should be quids in.  The house seems warmer as well, but that maybe because the back door is not leaking, and I sit at my desk opposite that door.  Mean house temperature has been 20.6° with a mean temperature difference of 8.8°C.

 

As some of you know, I am keen to reduce parasitic loads, and have very few.  Fridge (kind of essential, but still think 0.3 kWh/day is excessive), laptop (that is now mains only), 3 RPiZeroWs (could get away with 1), a cheap Weather Station (that I hardly look at as the outside sensor has stopped working) and a tiny 'pocket' router (which I can get rid of as it is only the energy monitor on it) and the CC energy monitor (could get rid of that as I made a similar one, but I like the display).

I have, this last week, made a secure TOR webserver (one of the RPIZeros) that at the moment is just logging and publishing outside temperature.  If I get bored, and trust the reliability, I shall shift all the data logging to this and just let it 'do its thing' but giving me remote data viewing.

 

On the downside of my energy usage, I have driven an extra 27,000 miles this year, on top of my usual 22,000 miles/year, but even there I have modified my driving style for economy and increased them MPG by 20% (other benefits are the car is still going at 220k miles, driving is generally less stressful, had a £270 speeding fine once and got banned many years ago, but only a £30 fine that time, now I stop everyone speeding), but it has cost an extra £4000 in fuel, and used an 2,300 litres, so about 23 MWh of energy.

 

Now the important chart.

 

 

 

Edited January 1, 2023 by SteamyTea

[ProDave]

Your last paragraph sums it up.  You spend more on motoring fuel than house fuel.

 

I am at about 8K miles per year, and that is expected to go down this year as I am retiring. Though it remains to be seen if I do more leisure driving instead of previous work driving.

 

Retiring is probably the best thing we could all do to help the environment. 

[JohnMo]

It's amazing the difference in outside temperature, between south and north of the UK.

 

But we'll done you on the saving.  I really need to get some monitoring done on our house, that could be my new year resolution.

[SteamyTea]

3 minutes ago, ProDave said:

Retiring is probably the best thing we could all do to help the environment. 

I semi-retired over 23 years ago, though I did have an interest in energy before then.

When I was working, I drove about 50k miles a year, one year, it was 70k.  And I had larger petrol cars and the truck.

One thing about reducing my working hours, and changing to evening working, is that my house is empty when most people have heating, lighting and entertainment on.  Coming home to a chilly house is soon sorted with a shower and bed.

Having said that, when I had a lodger, and once I had trained her up, we (it was a team effort) got usage down to between 4.5 and 5 MWh/year.  So long haired girls can reduce usage as well.

 

I am still not sure if my target of 3 MWh/year is good or bad.  I think, for a small, single person, household, it is reasonable, especially if I look at the ToU against CO₂ emissions.

 

[ProDave]

3 minutes ago, SteamyTea said:

I am still not sure if my target of 3 MWh/year is good or bad.  I think, for a small, single person, household, it is reasonable, especially if I look at the ToU against CO₂ emissions.

It shows how much the House uses, vs the Person.

 

We are using about 7MWh per year for 4 of us.  But if the other 3 moved out, usage would NOT drop to under 2MWh

[SteamyTea]

3 minutes ago, JohnMo said:

It's amazing the difference in outside temperature, between south and north of the UK.

Yes, but I am the exception.  Kernow is basically an island in the Atlantic, so is surrounded by warm seas, why I started to incorporate sea surface temperature, that, and I can tell the cold water swimming bores that it is not as cold as they claim.

My weather rose shows that my house is pretty stable, regardless of weather, the overriding influence is OAT.

 

7 minutes ago, JohnMo said:

I really need to get some monitoring done on our house, that could be my new year resolution.

Just get it done, being able to quickly check, and do indepth analysis is so helpful.

I have made it a hobby, and learnt quite a bit along the way.

I can now do basic Python programming, very advance statistics (though I did learn a lot at University an have a natural aptitude for it), how to make an energy monitor 

 

And best of all, can be smug about it.

[SteamyTea]

2 minutes ago, ProDave said:

We are using about 7MWh per year for 4 of us.  But if the other 3 moved out, usage would NOT drop to under 2MWh

Yes, that is why I am not sure if it is good or not.

May go and read my neighbours meters later, then see what they are in 12 months.

[MikeSharp01]

4 minutes ago, ProDave said:

But if the other 3 moved out

You should be so lucky.

[ProDave]

I don't have my own weather station, I just look at the data from this one, about a mile away, same valley.   https://www.wunderground.com/dashboard/pws/IALNES1

[ProDave]

24 minutes ago, MikeSharp01 said:

You should be so lucky.

I hope it won't be too long before 2 move out, but I want SWMBO to stay.

[MikeSharp01]

2 hours ago, ProDave said:

but I want SWMBO to stay.

Sounds like a good plan. 

[Marvin]

3 hours ago, SteamyTea said:

 

 

 

 

I @SteamyTea

 

It obvious to me from the graph that you are running at bottom power whilst still living! Do you have a hand bell at the front door?

 

The thermal efficiency of your property and or the inside temperature seem to be the only things where there is room for manoeuvre.

 

Like the windows ideas! We lose about 30% of the heat out of our windows. Had thought of insulated secondary demountable covers, but would have to convince SWMBO! I would try and mould the panels to the profile of the window opening by fixing a coat of plastic to the window and reveals cutting a bit of insulation the the right hight and width and then foaming one side of it a squishing onto the plastic. God help me if I make a mess of the carpet....

[SteamyTea]

15 minutes ago, Marvin said:

the thermal efficiency of your property and or the inside temperature seem to be the only things where there is room for manoeuvre.

I still have a bit of work to do on air leakiness, but as I currently do not have MVHR, I have to live with a bit of leakage.  Maybe dMVHR is the answer, but would need 4 of them, so maybe not, or two of them and a bit of ducting.  May try and add another 100 mm of loft insulation, but because it is a very small house (50m² TFA) loft space is useful.  There is some air leakage between the loft and the main stud wall that needs looking at, but that means pulling up the boarding, so a spring job.

I would like to have a warmer house, I grew up in the tropics, but I can live with 20°C ish.  23°C is my ideal.

Someone on here was going to buy an internal wall mounted ASHP that has the inlet and extract though the wall.  Keep meaning to find the thread again and see if they got one, and how it is working.  One of those in the living room would heat the whole house I think.

My mean power, for everything, is 360W, so 7W/m².year, which I think is really small.  3 kW_p of PV on my SW facing roof, and a couple of kWh of battery storage would make a very big dent in my usage, especially if I diverted the rest to the DHW.  6 kW_p would probably mean I could go off grid, but would have to steal my neighbour's roofs.  As I am 200m above sea level, and one of the highest building around, I would only be happy with roof integrated, not because of the structure, more to do with noise. 

The main problem is when usage is low, any news purchase does not make much sense once the basics are covered.

A more economical car would be my best current saving, but I currently need something that can do 300+ miles at zero notice, so that can wait.