Author: sustainablesilchester

1st Silchester Guides Presentation

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Stop Climate Change

1st Silchester Guides gave a presentation to the Greening Silchester Public Meeting on how they felt about Climate Change.  This is what they had to say:

We will be talking about making Silchester greener, mainly climate change. If the globe continues to become warmer, the icecaps in Antarctica will melt and the native species will become homeless and die out. For example, penguins and polar bears. 

To avoid this, we should all do our part by continuing or starting to turn off the lights, use less petrol fuelled cars. If we do this we should begin to see positive changes in the world. 

Thank you for listening.

Tackling climate change is important to me because I am a part of the next generation and I wanna be a part of the world that isn’t full of global warming and dirty air. I think we should tackle to eliminate change so we don’t destroy the earth for the future.

I think to help tackle climate change we should: plant more trees, so there is more oxygen, go litter picking regularly, recycle more like paper and plastic, wrap up so you can turn the heating down. Spend less time on electronic devices. All of this and more will help save our planet and ourselves.

Lots of children and teenagers also like riding their bikes around, but if we don’t stop climate change, they can’t go out and actually enjoy being out with their friends.

I think it’s important to end climate change because loads of people around here have dogs and need nice spaces to walk their dogs and it gives them a chance- to let them off the lead.

So, try to recycle everything you can to keep Silchester as good as new.

I think it is important to green Silchester because we’re the new generation of people and it will affect us more than you. If we don’t stop this now, people who won’t be born for another 10,000 years will live in a horrible world.

Every year the sea rises 3.4 mm per year – Sea level NASA

If we did not recycle, then land fill will get bigger and that causes less space to live. Did you know that a singular plastic bottle take more than 450 years to decompose.

Climate change affects everyone, not just plants and animals. Multiple jobs rely on nature such as ecologists, geographers, conservationists and farmers. This will lead to a supply in demand in those jobs and will affect the economy. Climate change also affects trading and globalisation. Industries for exotic suppliers will become more common, leading to less trading industries.

I think you should buy electric cars because, less fumes will be released into the environment.  I also believe that littering will have to stop soon because it causes climate change and that will melt icebergs, which will lead to extreme flooding.  Our amazing planet will be covered with not so amazing blue.

I want climate change to stop, so I can live forever and animals can be happy.

 

I want to stop climate change as I want to live longer and save the animals. We need to save the animals, as they help us to live as they produce food for us.

You should turn off the lights to save electricity. Stop deforestation – stop cutting down trees.  Get an electric car it is better for the environment.

Turn heating down (at least 1), pick up litter – do a national pick-up litter day!  Recycling means more local recycled things turns into useful stuff.

Got to get the place more green, all over the world I’ve seen lots of people have been destroying it – you don’t even know you are doing it at all.  The Right thing to do with our world is not to litter even though some of you do. Even if you think it ok, its not at all so please do not litter.

Everybody should be nice to our wildlife, because all humans’ beings would not live at all without trees, because they produce 02/air and the trees take in all the carbon dioxide.

Not everyone is nice to our plantations, but you could help plants and living things, you can help like saving electric, so you can save your money to buy more plants and thing to help make Silchester more green!

 

Bat Walk 2023

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Bat Walk 2023

We were delighted to welcome Kelly Jones to lead a Bat Walk in August. Over 50 people joined us to meet our lcoal bats and find out more.

There are several different types of bat in Silchester, the smaller ones are the tiny Common Pipistrelles and Soprano Pipistrelles, which call at a frequency of 45 – 55 kHz, and the (slightly) larger bats, such as the Brown Long Eared Bat, which call at a frequency of around 20 kHz.

Kelly started by introducing us to a pipistrelle bat that she was caring for after rescue. It was a real treat to see one up so close.

She explained that if you do see a ‘grounded bat’ it is important not to touch it!  Call the Bat Conservation Trust, and they will send an expert, such as Kelly, to help.

Then, armed with bat detectors, we all set out onto the Common.  It wasn’t long before the first bat swooped low overhead, which Kelly identified as a Common Pipistrelle from the calling frequency of 45 kHz.  It was rapidly followed by several more bats, both Common Pipistrelles, and a larger bat that could have been a Brown Long Eared Bat.  We were all kept entertained listening to the clicks from the bat detectors, as the bats flew overhead, while Kelly told us all about the different types of bat, and answered loads of questions.

Kelly was a brilliant walk leader, and we all learnt a lot and had a great evening.  Donations made on the night were split between The Bat Conservation Trust, and Sustainable Silchester.

 

Living with a Heat Pump

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Last year I wrote about the experience of Retrofitting a Heat Pump in my home in Dukes Ride.  As you have no doubt noticed, it has been cold this winter, and a lot of people have been asking how our heat pump handled the cold weather.  The short answer is “just fine”, but for those that want more detail here is a bit more technical information.

Firstly, a bit about how our heating is controlled

We run our house at about 20oC.  It is maintained at this temperature by setting the climate curve on our heat pump.  The heat pump controller measures the temperature outside and heats the water circulating in our radiators to exactly the right temperature to ensure that the house stays at the same temperature all day, every day.  When it’s -3oC outside, the water is heated to 45oC, when it’s 15oC outside the water is only heated to 25oC.  It took a bit of trial and error to get the climate curve right for us, but now the house stays at the right temperature all the time.  We could keep the house warmer, or cooler, by adjusting the climate curve up or down.

What happens when it gets cold outside?

When the external air is colder, the heat pump is less efficient.  It still heats everything to the required temperature, but it takes a bit more power to do it, and because it’s cold we need to heat the water to a higher temperature – a double whammy!  There is a very good correlation between the temperature outside and the power that our heat pump uses over a 24 hour period:

The eagle-eyed among you will spot that the day that the temperature dropped to -8oC, the energy usage is a little below the trend line.  That’s because (as set) our heat pump climate curve only went down to -3oC, and so at -8oC we were a little under-heated.  Had the low temperatures persisted, I could easily have adjusted that. 

How much did it cost?

If I assume an electricity price of 34.04p/kWh and a gas price of 10.33p/kWh, how did we do?

I have compared our monthly electricity usage in heating our house this year with our monthly gas usage over the last year that we had gas (2020-2021). 

To breakeven, we have to use around one-third of the electricity than we would have used gas.  Most of the time we do, and over the whole year we will be about £400 better off than had we been on gas.  However, as it gets colder the heat pump is less efficient, so it does cost more in the winter and less in the spring and autumn.  This has been a cold winter, and we have spent £60 more heating our house over the last three months than we would have spent on gas.  However, as soon as the weather warms up, the heat pump gets more efficient and we expect to more than recover this overspend over the next couple of months.

So Why Have a Heat Pump?

A saving of £400 a year doesn’t pay for the additional cost of installing a heat pump, so why do it?

For the future of our children!  Our heating and hot water now uses about one quarter of the energy that we previously used.  That’s a massive 2.5 tons CO2 that we are saving each and every year, and this figure is increasing as the electricity grid decarbonises.  In a world where we need to reduce our carbon footprint from around 10 tons CO2 per person per year to nothing as quickly as possible, that makes a difference.

Have Yourself a Sustainable Little Christmas

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Christmas can generate plenty of extra household waste and Basingstoke and Deane Borough Council is urging residents to recycle more during the festive season.
 
To recycle more at home, choose drinks in plastic bottles rather that cartons and put them in your green bin after they are finished.  Any extra recycling that won’t fit in the recycling bin can be put in clear sacks next to it for collection. In dry weather residents can leave large, flattened cardboard boxes (max 1m x 1m) next to their green bin but make sure polystyrene and plastic packaging is removed first.
 
There are lots of other items that can be recycled during the festive season and throughout the year including paper, newspapers and magazines, food tins, drinks cans and aerosols.
 
If sending cards or wrapping presents, residents are advised to choose recyclable Christmas wrapping paper and cards. Wrapping paper often has glitter on it and is generally poor quality paper so cannot be recycled and needs to go into the grey waste bin but brown paper, with ribbon and cellotape removed, can be recycled. Choosing Christmas cards which do not contain glitter, ribbons or bows means they can be recycled too. If you are unsure about what can and can’t be recycled visit www.basingstoke.gov.uk/recycle or call the council on 01256 844844.
 
As in previous years, garden waste customers will be able to put their real Christmas trees out for collection with their garden waste from Monday 9 January. Christmas trees over 6ft need to be cut in half and decorations must be removed. Real Christmas trees can also be recycled at one of 21 drop-off points across the borough between Monday 2 January and Sunday 29 January 2023. For more information visit www.basingstoke.gov.uk/christmas-tree.
 
Glass recycling is very popular at Christmas, your glass box or glass bin should be placed next to your green recycling bin by 7am on your recycling collection day. All bottles and jars should be rinsed out and any corks or tops removed. Don’t overfill the glass box or bin as it will not be emptied and please do not put bottles or jars out for collection in any other container.
 
Residents can pick up a free green glass box from the council offices in London Road, Basingstoke if they have lots of bottles and jars to recycle this festive season. Visit Deanes reception between 8.30am and 4.30pm from Monday to Friday, alternatively call 01256 844844 to request delivery. A red 140 litre glass bin can also be purchased for £40 as an alternative to a box by calling 01256 844844. Visit www.basingstoke.gov.uk/glassrecycling  for more information.

Collection days will change over the Christmas break and the revised dates are shown below. Unless adverse weather affects bin rounds, collections should return to normal from Monday 2 January 2023. The crews will take extra rubbish sacks on the first collection after Christmas only and as usual they will pick up extra recycling too.

Normal collection date                                          Festive collection date
Monday 26 December                                            Tuesday 27 December
Tuesday 27 December                                            Wednesday 28 December
Wednesday 28 December                                      Thursday 29 December
Thursday 29 December                                           Friday 30 December
Friday 30 December                                                Saturday 31 December

Cabinet Member for Environment and Climate Action Cllr Hayley Eachus said: “Extra rubbish will be inevitable over the festive period but a lot of that can be recycled including glass bottles and jars, plastic bottles, cardboard boxes, aerosols, tins and cans. We can all make changes to contribute to a more sustainable start to 2023 and recycling more and wasting less is among them.”

There is more information on festive bin collections on the council’s website at www.basingstoke.gov.uk/festive-bin-collections 

Everything you ever needed to know about the Energy Price Cap, but were afraid to ask

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Everything you ever needed to know about the Energy Price Cap, but were afraid to ask

By Sustainable Silchester’s Energy Expert

This week Ofgem, the energy regulator, announced the headline figure for the energy price cap would rise by around 80% to £3,549 per year. Given the amount of ill informed comment in the press and social media, I thought it was worth writing a short blog about what the energy price cap actually is and what it means for you as a domestic consumer (nothing written here is aimed at business use).

A Brief History of the Price Cap

The price cap was introduced in January 2019 with the purpose of ensuring that bill payers who, for whatever reason don’t seek out a cheap price for their gas and electricity, wouldn’t be too badly disadvantaged by unscrupulous energy companies. In other words, it seeks to reduce the cost of loyalty. The cap sets maximum prices for the standard variable rate that bill payers or moved to if they do not opt for an alternative deal. The expectation was that most competitive energy rates would be set well below the standard variable rate. The price cap was never designed to protect us from the impact of soaring energy prices. Indeed, there is some evidence that the question of what happens if energy prices rise above the price cap was not fully considered when developing this policy.

Roll on three years and we have seen the unintended consequences of this policy.  Over 60 suppliers have gone bust leaving less than 40 remaining. The standard variable rate is now the cheapest energy price most people can access. And the price of energy is becoming unaffordable for the much of the population. The price cap will not solve the cost of energy crisis, but it is still worth understanding what it means in practice.

So a price cap of £3,549 means I won’t pay more than this for my energy?

Photo by James Feaver on Unsplash

I’m afraid not. The £3,549 figure is based on an average house (3 bedrooms, semi-detached) and an average family (2 adults 2 children) using gas central heating. We pay for our electricity and gas in units of kilowatt hours (or kWh).  A kilowatt hour is a measure of energy, broadly equivalent to boiling a kettle for 20 minutes, leaving an LED light bulb on for a week or one tenth of a litre of petrol. Ofgem’s average home uses 2,900kWh of electricity and 12,000kWh of gas each year and this is used to calculate the headline figure. If you use more than this average amount you could end up paying substantially more than £3,549. If you use less energy you will pay less. Furthermore, it assumes you pay by direct debit, if you chose to pay by cash or cheque it could be up to £215 higher while a pre-payment meter may cost an additional £59.

If I’m not paying £3,549 what am I going to pay?

Alongside the headline figure, Ofgem also publishes actual energy rates for each area of the country.  These are divided into a standing charge (price per day) to pay for the costs of being connected to the gas or electricity grid and a price per unit of energy used.  For Silchester in the Southern electricity region our rates are:

  Gas Electricity
Energy Price 14.88p / kWh 52.07p / kWh
Standing Charge 28.49p / day 44.41p / day

So if you can find how many units of gas and electricity you used last year from your previous bills you can calculate your expected costs for this year. For a standard variable rate, gas and electricity customer paying by direct debit this would be around £266 + 0.15 x  [your annual gas usage in kWh] + 0.52 x [your annual electricity usage in kWh].

Does the price cap mean my energy bill is going to go up?

Not necessarily – many people are not on the standard variable rate, having chosen instead to fix their tariff for a period of months or years at an agreed rate. These rates are fixed for the duration of the contract and unaffected by the price cap.  Some energy companies are still offering fixed tariffs but they all tend to be significantly higher than the standard variable rate.  Still if you expect rates to go up further (as most commentators do) this might be a sensible option to protect yourself from future rises. 

I pay the same amount each month – how is this going to change?

Most energy companies now bill a fixed amount every month based on a projection of what you are likely to pay over the course of a year.  This means in the summer you pay more than the energy you actually use and in winter you pay less. Over the course of 12 months it should even out.

Energy companies have been criticised for significantly over estimating these monthly payments leading to people building up a substantial surplus – or (to put it another way) lending money free of charge to the energy companies. A change to the price cap provides an opportunity for energy companies to increase the amount they collect and you should be careful this increase is reasonable.   Divide the amount you expect to pay over the next year (see above) by 12, and if this is not close to what your energy company is proposing as a monthly rate you can challenge them and ask for it to be reduced. If you have any difficulty with this, then Citizens Advice Tadley can help.

Are we all doomed?

Few of us can easily afford energy bills of the level indicated by the price cap. Whilst the government is likely to provide more short term help over the winter, the fact remains global energy prices have risen massively and any reduction in bills is going to have to be paid for somehow, somewhen and by someone.

However, there is a lot that we can do to reduce our own energy bills.  Sustainable Silchester has plenty of advice on the topic, see Home Energy. 

An electrical device drawing only 1W left on all the time now costs £4.50 per year.  As fridges get older, the refrigerant leaks out, and they have to work harder to keep cool.  An old fridge might be costing you £450 extra every year, an you wouldn’t know that there is anything wrong with it. 

If you have a working smartmeter, now is the time to go round the house and check what is being left on, and how much energy it uses.  If you don’t have a smartmeter, Sustainable Silchester has a clip on meter that Silchester residents can borrow for a week to investigate.  Aim to get your baseload as low as possible – the average is about 150W, but below 100W should be achievable.

Glow Worm Hunt 2022

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Glow Worm Hunt 2022

On Friday evening Stephen, from Sustainable Silchester, led a glow worm hunt on the Common

At 9:30pm on a Friday evening in July,   35 local people met outside the Calleva Arms for a walk on the Common to hunt for glow worms.  Stephen started by giving a short talk about glow worms.  After 3-4 years as larvae, glow worms have a brief mating season for a couple of weeks in July, before dying.  The female glow worms glow green in the night (like a small green LED) to indicate that they are ready to mate, and the much smaller male glow worms fly around to spot them.   Each female has her own, quite large, patch so we were unlikely to see more than one green light at a time.

We set out at dusk, and it wasn’t long before three of the children spotted the first glow worm in a small gorse bush.  As it go darker, we spotted more and more glow worms, and cries of “I’ve found one” rang round the Common as Erin rushed around trying to record locations for the record.  In total we found 20 glow worms, although I have to say the children were much better at spotting them than I was.

Time flew by (like a male glow worm?), and I was surprised to find that it was past 11pm when we turned for home.

Why does Sustainable Silchester run an annual glow worm hunt?

Glow worms are not rare in the UK and they are not an endangered species. As a result, they are never a priority in biodiversity or conservation action plans (for example, the current Hampshire Biodiversity Action makes no mention of glow worms). Silchester Common is a Site of Scientific Interest but it is not registered as such because of the presence of glow worms.

However, although glow worms are distributed throughout the UK they require a specific kind of habitat and that habitat is not present everywhere. We are lucky that we have some prime habitat for glow worms here in Silchester. That makes their presence in Silchester something unusual for Hampshire and something to celebrate. Although glow worms are not categorized as red list or endangered in the UK their presence has been declining steadily over recent years (for example, see the Gardiner Report, 2011: –  Glowing, glowing, gone? The Plight of the Glow-worm).

There is no real data on exactly why this is happening but some of the principal causes which have been cited include habitat loss, global warming and increasing light pollution. More scientific study is needed to understand each of these effects in more detail. A further complicating factor in relation to glow worms is that they need very different habitats in their different life stages. In the larval stage (which lasts around 3 years and makes up 95% of their lifecycle) the larvae build up food reserves, feeding exclusively on snails and slugs. This requires a habitat which supports lots of gastropods such as in the taller, closed vegetation provided by the gorse and heather on the Common. In the adult stage (when the female glows) the habitat needs change. The female needs open areas of grassland in which to display clearly. This is provided by the grass margins and the rides on the Common.

So, it turns out that the Common, with its mixture of habitats is perfect for the glow worm. Who knows what will happen, however, if global warming continues to happen and the Common dries up so that it does not support a good population of snails or slugs anymore. Or what might happen if more street lighting and/or domestic lighting encroaches onto the darkness provided by the Common (there are lots of studies to show that the more light pollution increases the less successful males are at finding females).

So, for all these reasons, Sustainable Silchester takes the view that it is important to keep monitoring the presence of glow worms and have a readily available database of sightings built up over time so that this data can be used when making future decisions about the management of the Common and any development which encroaches upon it.

Thank you to all those people who have come along and helped with this project. We intend to continue in future years as the glow worm walk not only produces helpful data but it is great fun – people who have not seen a glow worm before are often genuinely delighted to see one for the first time.

 

Getting Started with Refillables

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Sustainable Silchester met Vikki from Ecosentials to find out how to get started with Refillables.

Refillables means topping up existing bottles and jars, rather than buying yet another plastic bottles.  Vikki is clearly passionate about the subject. “Not only do you use less plastic, but I choose environmentally friendly products that are kinder to the environment , better for  sensitive skin, babies and children.” 

So how does it work?

When you finish with a bottle, wash it out, remove the label, if you can and then drop it round to Vikki.   Vikki will refill the bottle and drop it back to you within a couple of days.  Vikki is based in Tadley, but also visits Silchester Market each month.  Any bottles dropped off at the market will be back with you by Tuesday. 

Some bottles are quite difficult to get the lid off, particularly duck shaped toilet cleaners, but Vikki was confident that she could get the lid off most bottles.

What are the most popular products?

Vikki didn’t have to think about that one!  The most popular products are definitely washing up liquid, laundry detergent and fabric softener, and toilet cleaner.  

A number of people have reverted to using bicarbonate of soda and vinegar to clean because there are no harmful chemical, and so she sells a lot of vinegar – often 3-5 litres at a time.  She also has a wide range of hand soap, shampoo and conditioner in different scents. 

Some customers just buy one type of product, and are happy with that, others buy from the full range.  Vikki doesn’t mind what people choose – every purchase is another bottle saved from landfill or incineration and that’s what keeps her motivated.

Sounds simple, why doesn’t everyone try it?

Well, a lot of people do!  Vikki has customers all round the area including Bramley, Sherborne St John, Baughurst as well as Tadley and Silchester, and many customers have been with her since the start.

The biggest barrier seems to be getting into the habit of hanging on to your empty bottle and dropping it round to Vikki, rather than putting it straight in the bin and adding another to the weekly shop.  However, once people get into the habit of refilling, they seem to stick with it, so Vikki knows that she is doing something right.

Ladies Clothes Swap and Social Evening

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Ladies Clothes SWAP and SOCIAL EVENING

Tuesday 24th May 2022

Silchester Village Hall 7:30 – 9:30pm

SELECTED RETAILERS

We will be joined on the evening by a few selected retailers to help accessorise those new clothes.  We are delighted to welcome:

Nivatali UK Handmade skincare

Susie P Accessories

Chapel Cards

Tropic Beauty products

Arbour Hollow Handmade beaded jewellery

Stylish Accessories

 How Does it work?

Enjoy an evening out & get a free wardrobe refresh!

1. Sort out any clean, good-quality clothes, shoes or accessories that you don’t wear.

2. Drop them off before the day at one of our drop off points and receive a voucher for each item accepted.  Items should be clean, ironed and if possible on a hanger

3.  Come along on the night, and enjoy a drink and a cake whilst you browse the items and our commercial stalls.

4. Exchange your vouchers for any other item that takes your fancy.

5. Additional vouchers will be available to purchase on the night.

drop off points

Contact Us

 

Sustainable Brownies

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Last week Sustainable Silchester were invited to visit the Silchester Brownies to launch our Sustainable Brownie badge.

We found out about things that produce carbon dioxide, and that driving a car just 1km would fill a large box with carbon dioxide.  We discussed how plants and trees absorb carbon dioxide.  When production and absorption of carbon dioxide get out of balance, then the amount of carbon dioxide in the atmosphere goes up, and this causes unstable weather like droughts and floods.   Then we put on a little play to show how our decisions can make a difference.

The Brownies will be working towards their Sustainable Brownie badge over the next half term, looking at what decisions they can make about what they eat, buy or how they travel can make a difference, and how they can help the local environment.

Finally the Brownies made some beuatiful posters to put on our recycling bins outside the Village Hall where we collect batteries, ink cartridges and clean aluminium foil for recycling.  Here are a selection of our favourites.  We will pick three to go on the bins.

Many thanks to the Brownies for inviting us, and we look forward to hearing about all the things that you have done as you work towards being a Sustainable Brownie.

Retrofitting a Heat Pump

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In November 2021, we decided to take the plunge, remove our gas boiler and have an air source heat pump fitted.  The main driver was to reduce our personal carbon dioxide emissions: our heating and hot water generated around 3.26 tons CO2 per year, and we thought that with a heat pump we could get that down to around 0.9 tons, and that this would reduce as the grid decarbonises.  However, I will admit that we were also curious as to how it would work.

A heat pump is essentially a fridge working backwards, extracting heat from the air and delivering it to our home.  If you burn gas in a boiler you get less useful heat energy out than the energy you put in.  The great thing about a heat pump is that, because it extracts energy from the outside air, you get more, useful heat to your home than the electricity you use to run the pump.  At least twice as much!  This ratio of heat energy out vs electrical energy in is known as the coefficient of performance or COP.  When it’s cold the heat pump has to work harder to extract heat from the air and therefore has a lower COP. As it warms up the COP also improves.  This graph shows how the manufacturer’s stated COP of our heat pump varies with the outside temperature:

Installation

The first stage to getting a heat pump fitted was to calculate the heat loss from our home.  Our supplier, Xpert Energy, created a model of our house, and calculated the heat loss through walls and roofs by room, both to give a total heat required to size the heat pump, and to that they could also check the size of radiator required for each room. 

We also had an air tightness test to check how airtight our home is.  This involved putting a large fan in our front door, raising the air pressure in the house slightly, and looking at how quickly this went down.  This was optional, but in our case worth doing, as our house is pretty airtight for its age, and having this evidence enabled us to buy a smaller heat pump.

Overall, the calculation said that at -3 oC, our house would need 6kW to maintain an internal temperature of 21 oC.

A heat pump is much more efficient when it is heating the water to a lower temperature, so the best strategy is to have larger radiators running at a lower temperature, or underfloor heating.  I had been afraid that every wall would need to be covered in radiators, but in the event about half our radiators were big enough already although we did decide to change most of them anyway.  The new radiators were all actually smaller and a little deeper than our existing radiators, so that was one fear allayed.

The installation took about 2 weeks.  It was more disruptive than it needed to be because of our decision to change all the radiators, and there is quite a lot of gubbins (technical term!) pictured below that we had to find space for.  On the positive side, we’ve gained a cupboard where the boiler used to be.  

We also had to have a new larger hot water tank. As the heat pump heats the water to a lower temperature than a boiler you need more water from your hot tap and less from your cold to fill a bath.  Fortunately, the larger hot water tank still fitted in our airing cupboard (just!).

I had been very nervous about how noisy the heat pump would be as Silchester is so quiet, but I think it makes less noise than the exhaust from a gas boiler.  So that was my biggest fear allayed.

We have a separate electricity meter for the heat pump, so we can see daily how much energy we used.   There is a very close correlation between external temperature and energy usage.  This is the data for November:

The benefit of this close correlation is that it is very easy to try different heating strategies, and quickly see the effect on energy usage.

For interest, I also looked at the correlation between our gas usage and external temperature.  This was our gas usage for November 2021:

 

Heating Strategy

We now have a thermostatic radiator valve (TRV) on every radiator, separate upstairs and downstairs heating circuits with thermostats, and the heat pump regulates the temperature at which it circulates water depending on external temperature.

We had been told that the most efficient way to heat our home was to leave the heating on at a steady temperature all the time.  This seems counter-intuitive.  Since the house loses less heat when it is at a lower temperature, surely it is more efficient to only heat it when you need the heating?

After experimenting for the last 3 months, I can report that they were right!

Initially, we tried to control the heating like we did with a gas boiler, setting the temperature to warmer in the mornings and evenings and cooler overnight and during the day.  However, we struggled to get the house warm at the right times.

After a while, we stopped changing the thermostats and reduced the temperature at which the water circulates round the radiators by a couple of degrees so that the thermostats rarely do anything.  The house got warmer, it felt more pleasant because the radiators were always on and the energy usage didn’t go up.  I’m told that in Sweden they don’t bother to fit thermostats to houses at all – the heating is simply controlled by sizing the radiators correctly and adjusting the water flow temperature and I can now see why.

I think that the reason is that reducing the temperature at which the water goes round the radiators by 2oC cut our energy usage by about 10%, which compensated for the slightly higher average temperature in our home.

Cost

One of our criteria for fitting a heat pump is that we didn’t want our energy bills to go up as a result, so how have we done so far?  January is traditionally the month in which our heating bills are highest.

In January 2021, we used 2741.9 kWh of gas, generating about 600 kg CO2

In January 2022, which had a very similar average temperature, our heat pump used 962 kWh of electricity, generating about 170 kg of CO2.

Utility prices are in turmoil, but at our current prices the energy used by the heat pump was 10% more expensive over the month than gas would have been (not counting the savings on the gas standing charge).   Since the heat pump is expected to be less expensive than gas as the weather warms up (I think the breakeven point is about 6oC), so far it’s looking about where we expected it to be.

Overall

Heat pump in situ

It’s taken a couple of months to get used to it, but we are very happy with our heat pump.

The temperature of the house is much more stable, and generally warmer than we used to have it when we had a gas boiler.  We cut our carbon emissions in January by about 400kg, and although not the most beautiful piece of kit, our heat pump is quiet and delivering the expected performance.