Finding the chase and cutting to it

It wasn’t a terrifically warm or sunny Easter, but the week after it was. Time to erect the sail shade I had bought last year.

You waited eight months before putting it up?

When you put it like that, it sounds like a missed opportunity. However, there were reasons, not limited to the fact I couldn’t see how one person could do this on their own. All the shows I’d seen where a sail shade was featured had a team of people doing the task. Was it even possible that two people could install one safely?

1. Sails need anchor points and until the French doors were put it, we didn’t have a good one on the house.
2. Winter is not the time to be erecting a sail – no matter how waterproof it is, leaves, snow, heavy rainfall, and high wind do not make for good weather to be raising a sail.
3. We would not have been able to enjoy the sail, all the while, it is exposed to harsh conditions which would wear it out.

I have been patient and two weekends ago, we started to plan to location and install.

You make it sound like a military installation!

A little bit. Sails need to be secure: being waterproof is not enough to guarantee that once it is up, it won’t collect water, putting enormous strain on the fixings and to what-ever the fixings are attached.

Counter-intuitively, tautness is your friend and that allows water to run off and wind to skip over the fabric. That means the fixings need to be firm and attached to something strong.

Here comes our balcony, which needs to with-stand 1.5kN/m², so a very heavy individual can fall on to it and not break their neck falling to the ground because the rail has failed. The barrier is assured to do that. The sail can exert around 550N in a 60km/h wind. That’s one fixing point.

Of course, the nice shiny barrier is not something we want rubbed by a rope or metal fixing. An Augo Heavy Duty soft loop is our friend here, built to secure goods on ship and on HGVs, they form a strong fixing point for the carabiners that came with the sail.

Next fixing point is one of our fence’s steel reinforced concrete posts. The Augo straps came in handy here, being just long enough to be fixed round the post with a carabiner and a turnbuckle to secure the sail, and give us the chance to tighten everything up once in situ.

Finally, our courtyard has a double layered 1.8m wall on one side, allowing an anchor point to be fixed to the top of it.

The sail came with turnbuckles, rope, and carabiners. With the Augo straps, we were all set to go. Last night, we did the deed.

Only to find that while we did raise the sail, it was a little baggy. Remember how I said tautness was our friend.

Yes, but I really don’t see why some sag in the middle is such a bad thing!

A 5m equilateral triangle (which is what our sail is) has an area of 10.83m². (This is from Pythagorus: a 2m equilateral triangle has a √3m height. A 5cm triangle is two and a half times as big, so it’s height is 5√3/2 – a triangle’s area is a half base time height, so that 5/2 * 5√3/2 = 25*√3/4).

Any chance it has to “billow” makes that a huge area, up to 4,970N for a windspeed of 25m/s, it’s why sails were so effective in powering ships.

The same chance to billow, provides a reservoir for rainwater. A cm of water on the sail is equivalent to 500kg!

The sail being as taut as possible harms no-one.

But with the nylon rope that came with the kit, we just couldn’t get it the materials to work for us. Having seen steel rope used for other sails, I bought a 4m, 4mm 7×19 grade section of rope from our local chandlers. A pair of thimbles and four wire grips, and I set about attaching the steel rope to two turnbuckles.

As we already had the rope up from yesterday’s efforts, I put in the cable.

As I started tightening it, I realised I hadn’t removed the old rope. At which point, I had a problem to solve as I hadn’t done something which would have made the task a hundred times easier. Simply putting the turnbuckle hook outside of the rope would have allowed me to easily remove it. Instead I wasted twenty minutes sorting that out, but it was a much easier job to do on my own that initially putting up the sail.

Because the steel rope is rigid, the turnbuckles give a set tension. It pays, from that point of view, to tighten the rope either first thing in the morning or just before sunset. That allows slack to be built in for when the sun it at its apex. I am now waiting for that moment to come.

Of course, to get it really drum tight, a lever can help me achieve that. From my engineering days, I am going to use a chisel blank I made in 1995 to help me get those ropes as stiff as a tuned guitar.

We’re finishing that tightening this evening, so we can enjoy the sun and shade for the rest of the summer.

You called this article “Dark powers”: not sure this is what I was expecting…

As a child, I was taught you can shade something to keep it cool or try to cool it after it gets hot.

Shading something is always easier.

Having put everything in place and down on paper, I think it could be done by one person next time.

Words to the wise: the majority of this paper is our usual exploration on how you can see the impact your efforts make in your home.

I do include the actual mathematics at the bottom to explain where some of this has come from – you do not need to read this unless you want to!

The past few weeks we’ve been examining sustainable heating. I’d like to take that to the point where we start to look at how we can put a value on the steps we’re taking by using what is at there at our finger-tips.

U-values tell us how effectively our infrastructure (windows and walls and insulation) helps us retain the heat our systems put into our rooms. Each component has its own u-value and we can add them together to get a total.

But this is not a simple sum on paper, because much of the material of our houses are built with are hidden from us: we tend to buy completely built houses without the choice of materials being given to us. EPC’s give us an estimate, but unless you have been lucky enough to witness the builds, that is all it is.

Working out our u-value.

Let’s see if we can’t “reverse engineer” our total/effective u-value, by observing what is happening in real life. We are going to do this for our louge by looking at the change hanging curtains up will make.

This is the day before the curtains went up:

We can see the drop in temperature over night, from 22.2°C to 18.5°C by noon! Tying that to our heat camera shows that even with it’s impressive u-value our patio door is a source of heat loss – to the turn of 7.5 m² * 1.2 W/m²K ≈ 9 W/K.

Words to the wise, a Kelvin is exactly the same size as a Celcuis – but the scale is off-set. This allows absolute 0 K to be -273.15°C, but 1K = 1°C. So, the 2.6°C we lose is worth about 24W of power.

Now, our tado thermostats and radiator valves log all the temperature changes over the past few years. But since we have had our new window, we have not had the curtains – so while I can look at the data from the last week of November and see that 2-4°C is lost almost all days. We can also see our solar gain in action or the heat pump or the log burner.

The question is, will our curtains help to cut that loss? I will use a couple of days to verify the saving.

What was the results then? How much difference does it make to put your curtains up?

The day before, means the next day is the 17th January 2026. Let’s look at our tado app and read off what happened.

We close our curtains at nightfall, actually, I get the lights to come on 10 minutes before sunset which acts as a prompt to get up and draw the curtains. They are then opened about 7:45am the next morning.

We can see that overnight, the temperature drop is about the same but is much shallower until the curtains are opened, about 1°C. Now, we don’t have that much sun coming through the south window on the 17th January 2026, proven by the fact we only generated 1.9kWh from our solar panels that day!

In fact, the tado is passing that information on to use! See the clouds in the various time zones? We can see that we don’t have very much in terms of solar gain. But the biggest difference between the two days is the starting temperature when the heating kicks in.

• Saturday 17^th Jan, when the heating came on the temperature was 18.5°C.
• Sunday 18^th Jan, when the heating came on the temperature was 18.8°C.

0.3°C doesn’t sounds like much of a difference between the two shows, but it shows a big improvement in our u-values for the room, because of the save in terms of energy drop, or how much of the heat was conducted out of the room over the 12 hours in question, this is precisely what the effective u-value measures.

Curtains are not a simple addition, they need choosing, hanging, drawing, but it helps us calculate our u-value. We’re going to scrap some historical data first from https://www.timeanddate.com/weather/uk/ for our town and the 17th January. Between midnight and midday, the average temperature 6.9°C, given the room is 52m², we can see an obvious temperature drop of 4°C. So, we can assume our u-value for the entire room was 0.134 W/m²K.

Now, let’s look at the difference the curtains made: the estimated u-value was 0.121 W/m²K, we had only a 1.1°C drop but the outside temperature was an average of 6.5°C, so there’s actually more being done on that day.

The u-value is how much heat is transfered through an element of a building, or the heat conductivity and the lower the number the better. For both of these nights, the temperature outside was similar but the drop was dramatically different. In fact, on the day we had a smaller drop, the weather was cooler.

One addition has made a big difference to this room, thermally lined curtains. Nothing else is different.

I can quote you the fact the walls have a u-value of the walls is made up of the following layers:

Layer	Material	Typical Thickness	R-value
External Leaf	Standard Red Facing Brick	102.5 mm	0.17
Cavity/Insulation	Rockwool (Mineral Wool)	50 mm – 100 mm	2.7
Internal Leaf	White aircrete blocks	100 mm	1.1
Internal Finish	Plaster/Plasterboard (assumed)	13 mm	0.33

Total R-value = sum of the r-values for each layer = 4.3.

Wait a moment! What is an R-value?

We’re getting to that. An R-value is the “thickness” of a material. A thick winter coat is much warmer than a summer one for exactly that reason: it has a higher r-value because it is thicker and more insulating. We can also think of it as the opposite, or inverse, of the u-value, to such an extent that the:

• u-value = $1 ÷ (r-value)$ => $1 ÷ 4.3$ ≈ 0.23 W/m²K.

That’s all the walls in the lounge, as with If it’s all about the green part 1, we can then work out what that means in terms of electrical energy retained.

Now, we have our patio door, u-value = 1.2 W/m²K, and our triple glazed doors and windows, they are 1 W/m²K each, and we know our observed u-value comes to a total of 0.121 W/m²K for the entire room.

So, is that curtains for heat loss?

Doh! But they do seem to make a bit of a difference, don’t they?

Now, we’ve got some accidental things we seem to have done right. The curtains reach the floor and there isn’t much of a gap at the top. We could probably achieve more if they did reach the ceiling – there is less of a path allowing heat to escape.

They are thick, and therefore heavy, curtains, fully lined with an extra thermal layer. They are gathered, all helping to make them thicker and less conductive. They overlap themselves by 50mm and they go past the window edge, again less of a path for the heat to escape around.

Five years ago, I replaced many of our venetian blinds with roller blinds, and found similar impacts. We finished the last one of these in our bedroom, when we swapped out our smaller window for a set of French Doors. One thing I wasn’t expecting is the difference the balustrade made the French doors in terms of protection from the elements!

Out of interest, where did you come up with the u-value?

Ah. U=Q÷(A×t×ΔT).

Where
Q = heat loss in terms of joules .
A = area of the room = 110m².
t = time in seconds or 12 hours in this case, 43,200.
ΔT = difference in temperatures or our temperature loss.

For the 17th January,

Q = Energy Lost=Thermal Mass×Temp Drop

Q = 2,196,850J/K×4.0°C= 8,787,400 Joules

ΔT = Starting temperature inside minus outside average temperature = 13.7°C.

So U = 8,787,400 / (110*43,200*13.7) = 0.134 W/m²K.

For the 18th January, Q = 8,128,345 and
ΔT = 14.15°C

so, U= 8,128,345 / (110*43,200*14.5) = 0.121 W/m²K.

I haven’t really said where the Q (thermal mass) value is, I’ve just quoted it. This is made up of the surface materials in the room, our flooring, plaster, heating circuit… these all store heat and are entirely unique to your home. You can ask an AI like Gemini to help you work out what your values are likely to be or ask a heating engineer!

When we got our solar cells, we were never looking to be off-grid. The move was to support us and our new electric car.

I had an interest in heat pumps, especially ground source, but in 2014, we saw solar as helping us ease the load.

Of course, the world has changed dramatically since then: war in Europe and West Asia has put pressure on fuel availability and that has impacted the price. As has our priority of our solar generation. Buying batteries in 2024 has meant we could have a back up for the house and limit the impact of getting an air sourced heat pump.

The 8th April was the first day in 2026 when we have been effectively off grid, we used a whole 500W (half a unit) from the grid.

How have we achieved this?

It’s been lovely and warm. That has taken pressure of the heat pump, allowing us to reduce our heating consumption.

Tuesday, 7th April, was really sunny, which meant that on Wednesday, we had 35% left in the battery when the solar generation took over supplying the house.

We did not compromise our lives on Wednesday, but shifted loads, like moving the hygiene cycle for the direct hot water system to the solar peak of the day. We also ran the washing machine and the tumble dryer later in the day.

I am writing this on Thursday, and at 13:43 on the 9th April, we are still running purely off the battery and the solar generation, though we should remember that the power stored in the battery was from our roof.

In fact, I am now cycling the dishwasher. But still running without taking power from the grid.

Of course, you were not the only ones doing well off solar!

No, we weren’t. The UK hit a new record for “max solar generation” beating last year’s 8th July record. There are a couple of things making that possible, but let us have a look at those figures.

Year	Date of Max Generation	Max Peak Generated	Total Capacity Available
2026	07 April	14.41 GW	~24.0 GW
2025	08 July	14.05 GW	~21.8 GW
2024	19 July	11.20 GW	19.3 GW
2023	20 April	10.97 GW	16.5 GW
2022	22 April	10.30 GW	14.5 GW
2021	28 May	9.30 GW	13.9 GW
2020	20 April	9.68 GW	13.5 GW
2019	14 May	9.55 GW	13.3 GW
2018	14 May	9.38 GW	13.1 GW
2017	08 April	9.15 GW	12.6 GW
2016	04 May	8.20 GW	11.4 GW

2026 has felt cloudy and overcast, but this is not the first year the max generation record has fallen in April. Why should that be? Photovoltaic cells (solar panels) work best in three scenarios: the right amount of light, the right temperature, the right angle of incidence or the angle the light hits the panel.

Cooler temperatures in April allow the cells to work at peak, while the angle of incidence is steep enough to allow fixed panels to capture most of the light. April has an average of 12 hours of generating time in the UK.

Of course, not being on the equator means our winter generating time is lousy, but in the summer, we can get up to 16.5 hours of useful time. If your photovoltaics are geared up to enjoy it.

In both solar farms, and the typical house, we tend to put solar panels facing in one direction. That does indeed make the most of the southern aspect. But it means the cells are not geared up for our seasons.

I feel this is a missed opportunity, especially as we move to using electricity for more than lighting and cooking. Even if the power is not 100% as good throughout the day, the longer period is worth a great deal in providing power independence.

The TechoSolara app is one of the few applications that can allow you to explore what making use of different aspects can mean to your solar generation opportunities during the longer days of summer.

Why not see how you can make the most of your home’s potential to generate power throughout the year?

Was it all worth it? The hardest thing about a purchase like windows for your house is that feeling you don’t know if it was worth it. It feels intangilble.

Even thermal imaging is a hard thing to assess because bricks have a high thermal mass, or in terms of house insulation efficiency a low R-value, the rate at which they conduct heat. It means they can act as a thermal store, masking what the windows are actually doing. Making use of my jet lag, I propose to do a cold study. It has just turned 5am on the 28th February, shall we see how well the new windows are actually doing?

Inside, the temperatures are seen below – every room bar the garage has at least one thermostat in it, reporting how warm the inside of the rooms are.

Shall we see what is happening outside?

As we were back from the west coast of Canada recently, I took advantage of being heavily jet lagged and went outside at 5am on a cold February morning.

I do not want to encourage you, but what were the results?

You should be able to see the images I captured. Basically, at this time of night, the heat gained by the bricks over the day, even in winter, has been lost, so we can see just how well the windows are doing.

Some things to note: we didn’t do anything with the garage doors. We also have the trickle vents open on the windows.

But basically, the windows are not losing anything like as much heat as they were. The trickle vents are losing heat – that’s their job, to take hot, moist air out of the house.

Our dormer windows have some tricky bits. Over the summer (when it’s more comfortable in the loft), I will look at where the gaps round the cheeks of the dormers are.

The triple glazed windows are outperforming the double glazed ones considerably, but even there, the loses are minimal, less than 5°C aside from the trickle vents! The triple glazed ones are losing less.

I often talk about the benefits of curtains for creating layers of insulation. Looking at the Juliet balcony, we are seeing that layering effect in action! We have the curtains, the double glazed french door, and the balcony – that’s four layers.

In April, I talk about how these layers all work together to provide a room’s energy performance. You can see the numbers working to keep you snug and warm and why it makes such a difference.

You still have some loses through the windows?

Yes, we do. It’s really difficult to get a zero loss house and have a building you can live in. You need windows, you need doors.

The aim is not to eliminate the loss but to minimise it.

The window loses being minimal has exposed where we have loses in our dormers – we have four dormers on the south side of the house and three on the north.

Dormers are notorious being difficult to insulate. During the summer, I will be looking for gaps and bridges in the insulation up in the loft. I think we have a bridge point in a girder in our wall in the lounge (Picture number 10).

The dormers will be fiddly, but should be DIY task. The lounge girder might be something we do last.

The roof looks solid at this time of night. Very little heat is escaping through the roof. If we can match the dormers to the specification of the roof, we should be in a good place.

So, still some work to do, but it looks like it was all worthwhile.

There are about 30 million dwellings (residential buildings) in the UK.

As of early 2025, over 1.4 to 1.6 million of these have solar generative capability. Only 44,000 are making use of solar thermal panels. With the rising price of energy and fuel, is that likely to change?

Owned versus rented.

One of the biggest obstacles are that people are less likely to invest in solar technologies if they don’t own the building they are living in. Around 10.5 million homes are in this situation. At which point it becomes the property owner’s responsibility and as all rented homes need to be a certificate C by the 1st October 2030, and solar panels are an easy way to do this.

Challenging some assumptions about solar.

So let’s look at what is holding the other 17,900,000 buildings from doing this.

I have lease hold.

People are worried that their leasehold might not permit them to install things like photovoltaics or solar thermal heating panels. So, ask whether that assumption is right. What’s the worst that can happen? You already don’t have solar, and they might say yes.

It’s too expense.

If you haven’t looked at solar in a while, the prices might surprise you. 4kW systems come in for between £5,000 and £8,000, including installation. Scaffolding for taller buildings does make it more expensive.

It’s not worth it without a battery.

We had solar for 10 years without a battery, and it was definitely worth it. We have a south facing roof, which is perfect if someone is in the house all day, but it means we don’t have meaningful generation until 8am in the summer and 9:30-10am in the winter. We also don’t have much, even in the summer, during the early evening, when we could actually use it.

Which brings us on to the most common misconception.

It’s only worth it if you have a south facing roof.

It’s true that the peak of the sun’s path falls to the south (in the UK, obviously the north in Australia, Argentina, etc) all year round.

But in the winter, the sun rises in the southeast, and in the summer, it rises in the northeast. So, south facing panels lose many hours of potential generation in these early hours. The sun sets in northwest in the winter, and southwest in the summer, again meaning those due south facing panels are missing hours of peak time. This results in the familiar dome shaped pattern of generation.

If your panels were on the east and west, those shoulder levels would fill out with a big dip in the middle. Here’s the comparison, drawn by Gemini.

The total would be a little less, 18.2 kWh compared to 22.4 kWh. But that’s a fair amount of power.

With 3-4 people living in a home, the total typically used in a day is approx 11.4 kWh and most of that is consumed in the following way:

Time	Appliances using electricity	Amount of power used
00:00 – 07:00	Sleeping.	2.1 kWh
7:00 – 9:00	Showers (electric showers are massive power draws), kettles, toasters, and hair dryers.	1.5 kWh with peaks of 3kW for boiling a kettle.
9:00 – 16:30	Fridge-freezers cycling on/off, routers, standby devices, and background heating.	2.5 kWh (typically 0.3-0.5 kWh per hour).
16:30 – 20:00	Cooking dinner (oven, hob, air fryer, toaster, kettle), lighting, TVs, and laundry.	3 kWh, which peak loads of 3-5kWh to warm oven or boil water.
20:00 – 23:59	Entertainment time and sleep.	2.4 kWh.

So, having a south facing roof isn’t great during the working week.

Given that the typical cost of electricity is £0.2769 that day has cost us £3.18. So a year’s usage is £1,159.10 just for the working week, we then have 104 weekend days where that rises slightly, so our 11.5kWh heavy power user is the spending 14kWh during the week (more home cooking, TV watching, etc). So 14*104*£0.2769 = £403.17, giving an annual bill of £1,562.27 plus the standing charge.

If those east-west panels can ease that by 18.2kWh on a good spring day, doesn’t that cost in, especially as you wouldn’t have the outlay of batteries?

So, we should look into it?

Yes, it really is worth considering. But do think about what you need. As a heat pump owner, our south array of panels are not ideal without changing how our heating works or buying batteries, and I would say that the former is more cost effective.

We are examining having east and west panels to cover the morning and evening load. The battery would then be there as back up for a cloudy day.

You could use an app to do a self-assessment: I happen to know of one being launched on 6th April that will allow you to work out if your roof geometry if viable! Or get an installer out, who can do a full shadow analysis and recommend what you should do.

Of course, if you have a garage or garden, solar panels on your roof is not your only option. I know three people who did not want to put panels on their roof, so had a ground mounted array. A sturdy pergola could support an ideally facing array that could be clear of shadows…

Please note that on the first of April, the capped electricity prices in the UK will drop to £0.2467 per kWh. It is widely expected that will be short term relief as Ofgen is likely to put the cap back to £0.27 or possibly higher, depending on the current restrictions on the transit of oil.

NB the graphs shown are real but idealised days with little cloud cover and no shadows falling on the photovoltaic panels in late March 2026. It is true to say east and west panels do not give the same maximum potential, but in many cases they may provide a more useful pattern of generated power.

11.5kWh of week day usage is a high consumption rate in the UK. By comparison, highly efficient households use much less. To work out your average, make use of your smart meter or take a measurement on the 1st of next month (ideally at midnight), and a measurement of the last day of the month (ideally at 23:59), and divide the total for the month by the number of days. In most working households, where the home owners who commute to work, the weekends typically use 1.3 times as much electricity as the average weekday.

Mothering Sunday was not originally about celebrating Mother’s Day – it’s an old age tradition where people returned to their “mother church” – the main parish church or cathedral where they were baptized or raised. This act of returning home is the original meaning of “going a-mothering”.

It is celebrated on the fourth Sunday in Lent, the lead up to Easter and the equinox (equal day and night, only not really in northern latitudes like the UK). Easter is set as the first Sunday after the first full moon (the “Paschal Full Moon”) occurring on or after the spring equinox (March 21). So, Lent and Mothering Sunday change date every year.

For my usual category of Driving off The Grid, equinox and equilux (properly 12 hours of each in the UK), we care about this because the equinox is the begining of Spring and better chances of peak solar generation.

This year was no exception, as the pie chart from NESO shows: one of the first days in a long while where our zero carbon generating sources featured solar power.

The past week, our electricity has come more and more from our own photovoltaic panels, and any excess we have generated is put into the batteries first.

Obviously, this is important at the moment as energy prices are likely to be volitile for a while.

Living in a rural part of the country, our local news has featured the rise in heating oil costs, and a number of people have had their oil drained by theives.

We were on the gas network; when we got the heat pump, we had our gas meter removed and the pipe sealed but not removed.

But the heat pump and solar cells will cushion us over the summer while chaos is happening elsewhere in the world. Not as much as we would be if the UK was not still using gas to generate 30-40% of its electricity. The move to renewables has never been more important to give the UK generating independence.

The graph I grabbed at 2pm on the 15th March 2026 is all the more important for the fact it does not feature any gas generated power.

How has the UK made the move?

The decision was made to place a green levy on energy prices to support the financing of zero carbon technologies and sources. But it has allowed gas prices to be significantly cheaper than using heat pumps for central heating.

Typically, the levy is 13% on a unit. Our unit price is currently £0.2695 ex. VAT, so the green levy means a unit costs £0.2384 and the levy is a whole £0.0310.

“According to the Insulation Assurance Authority, [the levy] has resulted in a reduction of over 26.2 million tonnes of carbon emissions and a reduction of fuel bills by a total of £6.2 billion.” [ https://www.theecoexperts.co.uk/news/green-levy ].

While the levy doesn’t account for much, because gas is so much cheaper than electricity, the efficiency of a heat pump does not look like it costs in for many people.

If we moved the levy away from electricity and put it largely on gas, that comparison would be much more compelling. There’s a good arguement to do that.

It would also make solar cells more attractive. During winter, generation can be hit or miss, highly dependent on cloud cover. But we typically generate 3.6MWh a year, 2023 is a typical year:

In March, with the heat pump, we start to break even in terms of getting enough solar power to dent our bill. By May, despite significant shading from trees, we are effectively off-grid and the money we pay every month is providing savings for the winter months. That and the SEG (Solar Export Guarantee) essentially pays for our winter heating.

I recently found an energy quote from 2008 where every unit was £0.089 – a whopping third of the price of a unit today and prices are rising.

The government could respond by raising the grants for moving to heat pumps for heating. But moving the levy to just gas would help encourage people who are needing to fix or replace the boiler to see real benefit in moving to heat pumps. Ironically, in rural areas, where mains gas is rarer, the uptake of heat pumps has been much higher than in towns, as being without electricity is much rarer in the UK than being without mains gas.

If you live in the UK, you energy company is probably making a big fuss about “Power Moves”. Part of demand flexibility schemes are operated by National Energy System Operator (NESO) as a means of ensuring the UK makes the most of the renewable energy it produces.

Power move, first launched by Ovo in 2024, looks at ensuring you use as little energy as humanly possible during peak times. Because renewable energy is only available when it is being generated, this should encourage people to make use of power when it is available, as much as possible.

As gas prices are rising at quite a rate at the moment (though nothing like as fast as they did in 2022 when Russia invade Ukraine for the first time), as seen in https://www.cliffordtalbot.co.uk/energy-prices/. Please see the image below which is a snapshot I took when I first wrote this article.

This graph is interesting because where gas prices rise, so too does electricity (and oil). While the UK has made great strides in becoming energy independent, we still generate 30-35% of our energy from natural gas and most of that is imported. Things like the action in Iran which exports a great deal of oil and gas, or transists other countries exports, make a big difference, at least in the short term.

The reason power move is so important is that it allows you energy providers to sell you renewable sourced electricity during the rest of the time and when peak demand is happening, they only have to fall back on gas sourced energy for the few who cannot avoid using power – like councils lighting streets and traffic signals, hospitals feeding patients and lighting wards, etc.

Power move rewards customers using power during non-peak times by charging a lower rate, and if they can avoid using power between 4-7pm Monday to Friday during the winter, or 5-7pm Monday to Friday during the summer, they get “prizes or credits”.

I know some using off-peak times to charge batteries which they then use during peak times and when their solar cannot power their houses. It’s not necessarily reducing their carbon footprints but it is allowing them to reduce costs with their providers.

Around 100,000 people are making use of Ovo’s Power Move to great effect and allowing the UK to reduce its reliance on imported gas.

Are you doing this?

The short answer is no. Being type 1 diabetic, moving meal times can be extremely difficult and that is our big use of power between 4 and 7pm.

I do heat soak the house during lunchtime, which reduces our pull on the grid dramatically. This is actually a good example of this in play:

You can see, on a relatively cloudy day, our solar generation was on 2.7kWh for the whole day, we used very little between 4pm and 7pm. Indeed, by heating the house at solar noon for two or three hours means we have a comfortable house, without having to draw anything from the grid.

Teamed with the uptick in our solar generation figures as we enter March, and it all looks much more feasible.

We’re looking at how we could encourage the battery to store energy during off-peak times, and use its stowed energy during the peak. This is standard functionality from many battery providers, allowing you to be off grid when it comes to cooking tea. If you didn’t have that functionality, you may need to do something manually.

Pairing this with ensuring things like using washing machine is done outside of the peak times, ideally during the weekend (we try, where possible to do our washing and dishwashing cycles when we are generating power, even in winter), and we typically only draw a few kWh during the cooking cycle. Which only lasts 20 or so minutes.

The kettle is one to watch. Switching on the kettle uses 3kWh for about 3 minutes for a couple of cups of tea. Making a flask of tea at mid-day might be the way to combat that or take the advice my mum was recently given in helping her sleep patterns and don’t drink sources of caffeine after noon!

And ventilation fans. Making sure these can be kept to a minimum can all help lower your usage during this critical times.

You’re considering it then?

Yes. We really are. It’s about making sure it works for us. The credits and prizes are less tangible than lower costs when it’s off-peak (who remembers economy 7). But it would mean energy sovereignty.

It’s my week to shop and cook. So, I am trying something new today, cooking my lovely left-over pie in the combination microwave.

The average UK home spends 3-4% of its energy usage on cooking. It spends 80% on heating. Which doesn’t make cooking sound as if it’s causing much of an issue.

But, our evening meals contribute to the peak draw on a week day evening.

Given, our heating was 3,966.20 out of 9,594 kWh usage last year, or 41% of our energy bill. Our car was 2,000 out of 9,594 kWh, so 20%.

As we’re keen cooks, let’s say cooking took 5% of our bill, that’s 479.7 kWh.

So, without switching to sandwiches of an evening, how can we do better?

Well, it’s one of the reasons the microwave is being deployed for the left-over pie. Instead of using the hob for 15 minutes, I cooked the filling in the microwave for 6 minutes at 1kWh. That gives us a usage of 100 W compared to 600 W for the induction hob.

Normally, crisping the pie crust takes 28 minutes at 2kWh, or 933 W. Doing this in the microwave will take 15 minutes, even if it uses the 2 kWh, that’s 466 W.

It’s not much towards the 479.7 kWh, but hopefully it is a step in the right direction. And much quicker to boot.

OK, I give in, what do the numbers all look like, please?

Task	Induction hob or fan oven energy usage (kWh)	Time taken (minutes)	Microwave or Combination microwave enery usage (kWh)	Time taken (minutes)	Power saving as %
Vessel heating for filling	~0.15	1	~0.01	0	93%
Filling precook	~0.50	20	~0.10	6	80%
Finishing off pie	~0.90	30	~0.25	12	72%
Total	1.55	31	0.36	18	77%

The microwave uses 23% of the power. It takes just over half as much time (well 18/31 = 58%).

So what did it taste like?

Pretty much the same as normal, it’s something we look forward to having each week, almost as much as cooking the roast on the Sunday before hand.

The food was just cooked in a fraction of the time and energy. In fact, I was so impressed, I am using the same methodology for the pudding we often do with the pie, a tart tart. Using the remainder of the pastry means we get to use the residual heat from the oven, so the pud is really economic.

These are not new concepts. When ovens were powered by wood and coal, the Sunday lunch was often followed by cake or bread, soaking up the residual heat. It also made short work of food that went off in the cold store, like eggs, milk, and butter.

Of course, most working people do not have the time or energy to do that. But when everyone cooked their bread at home, a roast joint popped in the oven afterwards on a Sunday was basically free cooking. As was the scones or cake for a high tea…

Makes sense, so how did that experiment go?

The initial timings were a little off. Because the combination oven was pre-warmed, it didn’t need anything like the 12 minutes I cooked the pair of tarts for, but next time I will do better.

Taste-wise, it’s the same, energy-wise, it’s much quicker: so why don’t more people do this?

It’s a good question. 90% of UK and USA homes have a microwave.

There is a move towards combination microwave ovens, especially in smaller homes as they provide so much functionality in a smaller package. But cooking in a microwave is still seen as a bit niche.

For me, this is such as missed opportunity. Using 25% to 60% less energy for a cooking task means our 479.7 kWh pa on cooking goes down to a conservative 239.85 kWh. At £0.27888 per unit, that’s £66 pa. Or runing a tumble dryer for 80 hours.

Then there’s the washing up. The pudding comes for free as it uses the lid for the meat pie dish.

But usually, I would use a big pan to pre-cook the vegetables. This is no longer needed. I would have used oil to cook the veg in too, again another saving, and if I use the right knives, everything would fold into the dishwasher.

This is another reason I am making the effort. I am trying to start my own business, and until it is established, things are busy without bringing in any cash.

I need all the help I can get, and such differences do add up pretty quickly.

How are you making the move to using the microwave more?

Actually, Google’s Gemini is acting as my sous chef. Given an existing recipe, it’s quite good at making the conversion.

I give Gemini the link to my wiki recipes and ask it what the steps would be if I cooked it in the microwave. It was a little involved for this one as the recipe had the multistage cooking – going from the hob to the oven. First draft just gave me swapping the fan oven for the combination microwave: but a little coaxing meant I had everything being done in one pot and one device!

As per Zapping my way to the top, there are a few easy moves to make.

I do have some ground rules for sanity checking what Gemini says, but so far, it all seems to be positive steps forward. Good tasty food cooked quickly and cheaply: why not make that effort?

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I’m no saint. Yes, I have been the one to make the suggestions of looking into the electric car and the heat pump, but, like everyone else, there are big areas I, personally, should do better.

We are alpine skiers, and living in the UK, that means foreign travel to some mountains. Last year, we did the trip to France by train (if you are looking for an eco-friendly trip, this is the way to travel). In fact we did a great deal more eco-travelling than normal to off-set our trip to Canada this year.

I know, I know, two rights and a wrong do not make things good. But I should be able to do much less by car over the next twelve months too, and hopefully make more use of my push bike…

Your point?

Sorry. I was going to talk about the big difference in doing such trips when you have an optimised heat pump.

Before the heat pump, when the house was truly deserted, we would put on frost protection and run the house at a really low level. But, having got the windows done, and the curtains, it really isn’t the right thing to do for the heat pump. Plus my son and his girlfriend house sat for the weekends, so the house wasn’t really empty over the period…

What difference did that make?

Let’s have a look. We were away from 10^th February to the 25^th February 2026. The doors and windows were all closed, as were the curtains, and we can see that the usage wasn’t that different. The days when no-one was around, the usage was pretty low, but then those were much warmer days too. More importantly, they were sunnier too!

I did make a difference to the Vicare app, and turn down the settings for the flow round the heating circuits. Fewer doors (both internally and externally) means the temperature didn’t change as much, so we didn’t need as much heat flowing round the system, especially when teamed with room thermostats. I also stopped the post-tea warm up when there is less demand on the grid.

That sounds like jargon, what do I mean in practice? Well, in our living/entertaining areas, I have set the heat to come on again at 19:00 or 19:30 to take us through the part of the day when we’re more likely to be less active, talking rather than walking, so to speak.

The 17^th February in the lounge (I so want to say with the candlestick, but I will refrain), is a great example of this.

The yellow area is when we heat the room for a few hours in the afternoon, just post our solar peak elevation. We can see from the graph, that heating effect actually continues for much longer than the heating time itself. During this time, I am leveraging our solar panels, as this is when we’re most likely to be generating on a cold winters day in February.

Let’s look at the same graph after I had put the timers back to heat during the evening and returned the flow temperature back up a couple of degrees.

What’s interesting is while the heat is primed to come on, it doesn’t actually reach a temperature where the room is aggressively heated as it is still carrying the heat from earlier in the day. That evening heating is to keep the temperature stable rather than heating a cold room.

Let’s have a look at those heat settings for Thursday.

The solar soak is happening between 12:45 and 15:00 every day. To quote Google:

We are not making the “power move”, to ensure our usage is as low as possible during these times, but we feel every little bit we can do all helps.

I have set the lounge, offices, bedrooms and en suites to make use of these kinds of patterns. It’s not zero, but it’s not taking more than we need.

On a day where there wasn’t that much sun, we can see the corresponding peaks in our pull on the grid.

On a day when we are generating electricity, it’s really noticeable, even in February… Wednesday the 25^th February, while I was putting everything back to “normal” for our return, our house was drawing very little from the grid. We were managing to charge our batteries to take us through the evening.

These changes you’ve made are working then?

They do seem to be. Heating the house during the times we have energy from the roof, not drawing too much from the grid during peak demand are worth the effort.

Compared to usage up to the 26th February 2025, we have used 170.7kWh less electricity, about £45.25 (and last year the electricity was more expensive).

We haven’t changed anything else, and February 2026 has been cooler than February 2025, and darker. I can prove that because we’ve generated significantly less electricity than last year!

Oh, so that isn’t just you using less from the grid, you’ve actually used less per se!

We’re making it count. Both years have been using the heat pump, but getting the insulation right with the windows allows us to make simple changes to our behaviour without making us uncomfortable. Far from it, we are warm and the house is definitely working for us. Over the course of a day, the lounge is heated twice a day, as many people set up their homes, it’s just making the most of what we’re actually generating and using.

On the 26th February 2026, we were using very little power between 16:00 and 19:00. So much for electric heating making greater demands on the grid and we didn’t need to be cold to achieve this.