How energy-efficient are Charlbury homes?

Tue 4 Apr 2023, 14:40

In case you are wondering what smart heating is, it means every room can have it's own separate timer and thermostat.  So for example you can have your bedroom heated to 22 degrees between 9pm and 11pm, and your kitchen heated to 18 degrees between 7am and 8am.  

Tue 4 Apr 2023, 11:30

I didn't have time to visit the houses. I am only referring to the case studies of recommended work that were posted at the bowls club. BTW of course we have a smart thermostat. We have reduced our energy consumption to about half and are now at 80 w / m2 and year, which I think is not bad for a house that is close to 200 years old. This year should see further improvements as I am double glazing the front elevation. 

Tue 4 Apr 2023, 11:28

The costs of total refurbishment are high.  The point of a whole house plan is that it sets out all the steps, and in the order in which they should be done so that one step doesn't inadvertently make another difficult to do.  So no-one has to spend all the money at once - the plan can be paced.

Tue 4 Apr 2023, 09:18 (last edited on Tue 4 Apr 2023, 09:18)

Hans: I visited 3 of the open homes on Saturday, including Claire Wildings', and found all of them really useful in terms of thinking about energy savings -- even though none of them are much like the house where I live. Sometimes it was useful simply to rule out certain options that I had thought might be open to me; other times it threw up ideas that I just hadn't thought of at all. All the homeowners were extremely generous in sharing detailed information and technical advice.

None of the 3 home owners quite fitted with the Cosy Homes model of making changes which does seem very ambitious and also expensive. Thanks so much for the help of all those who opened their homes on Saturday, and also to the Town Council who organised the event.

Mon 3 Apr 2023, 22:08

Hannen, have you looked at smart heating? We use hive, which has cut our gas bill for very little upfront cost. If you already have thermostatic valves on your radiators you can swap them to a hive version for about £40 per radiator. 

Mon 3 Apr 2023, 19:09

I think this is a great initiative. I looked at some of the case studies displayed where it seemed that one needed to spend some £ 100,000 to reduce the cost of gas from £ 1,900 to £ 1,200 per year, I wonder if there is a middle way? 

Mon 3 Apr 2023, 17:12

We also found it really helpful - thank you to the people who opened up their houses and were prepared to share lots of useful information.

Mon 3 Apr 2023, 13:41

What a great day - a chance for me to meet new people from Charlbury and to have interesting conversations about the challenges and opportunities of reducing energy use in the home.  The Home Comforts project will be publishing a report with whole house plans for ten typical homes in Charlbury by Saturday 10th June (first day of Big Green Week) when the Memorial Hall will have an exhibition of the results, and probably presentations in the morning and afternoon to talk about the results - and next steps.

Sat 1 Apr 2023, 17:43

Thanks to everyone involved in facilitating this excellent, informative event this afternoon.

Really complex technical info was demystified which was really helpful! 

Fri 31 Mar 2023, 19:13

Our house is also part of open homes tomorrow, pop in to hear about how we've reduced our gas bill by 40 percent and our electricity by 60 per cent. And take a look at our solar and smart heating.

Fri 31 Mar 2023, 17:13 (last edited on Fri 31 Mar 2023, 17:26)

Just to say - ours is the house that Liz mentions in this thread. And yes its100m2 and uses about 4,000kWh/year. When we arrived the roof was leaking and needed to be replaced. We took the opportunity to super insulate it for only a little bit extra. We put up solar PV and hot water panels whilst the scaffolding was in place.

Then the boiler packed up! So we replaced it with a heat pump.

When we renewed the interior, we asked the builder to put in extra insulation at the same time. We've done some other things as well, including the heat-reflecting triple-glazing.

We certainly aren't perfect and we didn't have an unlimited budget. However we've cut our energy bills by about 2/3 whilst creating a house that is warm in winter and cool in summer. 

Its one of the homes open tomorrow.

Fri 31 Mar 2023, 10:12

Thanks Miles

Thu 30 Mar 2023, 22:08

Just to check Liz - the open homes is Saturday, not tomorrow (Friday) right?

Looking forward to it.

Thu 30 Mar 2023, 18:33 (last edited on Fri 31 Mar 2023, 10:12)

So Open Homes on Saturday 12-17.00 - start at the Bowls Club for a map - has homes with an air source heat pump and a ground source heat pump.  So you can ask the homeowners what their experience has been.

Also solar PV and solar thermal, wall, floor and roof insulation, a battery, and electric car, heat-reflecting glass ......  all sorts of useful things to learn about being comfortable at lower energy cost.

And there's sight of the drawings for a home that has planning consent for a series of measures - including raising the roof.

Thu 30 Mar 2023, 17:32

Halfway through that sliced bread on air source heat pumps there is an "expert" trying to claim that the cost of heat pumps are about the same as a gas boiler. a) because the heat pumps "last longer" than gas boilers. That we don't know at the moment because the heatpumps have not been around for all that long. False. b) "gas is now more expensive so the running cost comparison favours the heat pump". He doesn't know that electricity prices are directly linked to the gas prices through the pay-as-clear/merit order. False. 

Thu 30 Mar 2023, 11:38

There's a 25-minute episode of Sliced Bread on this topic

Thu 30 Mar 2023, 09:02

Air-to-water heat pumps use low grade thermal energy collected outside. The warm air is used to warm up water, which is pumped around the house in radiators or underfloor heating. It is easy to see how well this works. Grab a hair dryer and blow the warm air on the kettle and time the duration it takes to raise the water temp by say 20 degrees... 

Thu 30 Mar 2023, 08:55

Heat pumps are much more efficient at 300-450% than any other heating system on the market, at least when tested according to industry norms +7 outside / + 20 inside. But the running costs are about the same as gas is about 1/3 of the cost of electricity. Net zero means of course moving from fossil fuels to green electricity. It would however be a very brave politician who would make 90% of the population poorer (who use gas). What would help though is to reform the electricity market and remove the pay-as-clear/merit order market clearing where the most expensive method sets the price for all. That seemed to be the path for UK in June of last year, but that has now disappeared. We who watch the electricity wholesale market thought EU would decouple, but did not. The thinking is probably very influenced by Biden's Inflation Reduction Act.

Wed 29 Mar 2023, 15:15

Plus this new report by @StrathCEP

Explores the potential economic gains from heat pump deployment, considering the current market situation where the retail price of electricity is high relative to gas. http://bit.ly/3M0rrIB

The CoP (Coefficient of Performance) is really important if heat pumps are to be effective.  You're looking for at least three times the heat output from the electricity inputs.  (Happy to be corrected by a more technical expert!)

Wed 29 Mar 2023, 12:31

In response to Alex Michaels - just buying a heat pump which gives a higher temperature must of necessity use a lot more electricity at high cost.  I don't know if it will work, but here's a link to a Twitter thread which responds to various myths about heat pumps:

	Dr Jan Rosenow ⁦@janrosenow⁩ Myth 21: "Heat pumps are new and untested technology." False. The first heat pump as we know it today was built by Peter von Rittinger in 1856. Heat pumps were put in peoples' homes already many decades ago. twitter.com/CAHiggins/stat…   29/03/2023, 10:08

Tue 28 Mar 2023, 20:20 (last edited on Tue 28 Mar 2023, 20:35)

Nothing New is Needed - as Liz points out. I can point to Housing Coops in the 70s who did Zero Energy housing without the benefits of heat pumps, one of which I stayed in regularly when working on stuff with the Open University in the 80s. 

I again paste…

Long post - click to read full text

Mon 27 Mar 2023, 21:15

The Salford house referred to in the New Scientist article was first built in the 1980s and demonstrated many simple techniques for improving the energy performance of new homes. Mass developers still pretending that they still need research to make better homes. They don’t. They probably do need to train their workers to deliver to the necessary quality. Which takes care and paying attention to detail. 

Fri 24 Mar 2023, 23:30

You don't need to fit bigger radiators, etc. necessarily with a heat pump. Choose a heat pump which has a high output temperature (~65C) close to that obtained from a conventional gas boiler and a similar power rating, e.g. Vaillant Flexotherm (19kW) or RED HOT (16kW).

Fri 24 Mar 2023, 19:53

34 squid = cheapskate (sic) investment ! No chance of an infra-red analysis of hotspots surely.

I paste in below an entire copy of an article off the New Scientist magazine. I'm a subscriber so this might not be available generally to outsiders, hence entire pasting in. Its worth the…

Long post - click to read full text

Fri 24 Mar 2023, 14:09

Liz knows this but EPCs are not a very reliable indicator. As the assessor looks at typical u values for the different parts of the building, walls, floor, doors, windows etc and the level of insulation. They are not paid much, I just got a quote for £ 34! They are not able to do a proper thermal survey for that money. 

Fri 24 Mar 2023, 14:08 (last edited on Fri 24 Mar 2023, 14:09)

Hmm,  that database has every certificate ever issued for a property, so a D rated property that has changed hands 4 times since 2008 with no improvements will show up as 4 individual certificates. (see the FAQ related to accessing the database)

Fri 24 Mar 2023, 13:57 (last edited on Fri 24 Mar 2023, 14:02)

The other issues are that energy certificates are generally only generated when a property is up for sale, so any property that hasn't changed hands in the last 15 years (since 2007) will not have a certificate, and any property that has had significant work done since purchase will not have an up to date certificate. Most home owners will not pay out for a new certificate until they come to put the property on the market even if they have significantly improved the efficiency of the property.

Fri 24 Mar 2023, 13:04

The figures I give are based on Energy Performance Certificates registered with the government.  Sadly we know that many of these certificates are of low quality but that is all we have at the moment.

The town council is working with not-for-profit Cosy Homes (based in Charlbury), to improve the quality of the data for Charlbury homes and we hope to be able to share the results in June during Great Big Green Week.

Fri 24 Mar 2023, 13:03

Ian, as a scientist you could have great fun playing with the data, which is publicly available here: https://epc.opendatacommunities.org/ (wasn't hard to find) 

OX7 3 has 1996 certificates, of which 1 A, 159 B, 464 C, 764 D, 417 E, 153 F and 38 G. 

Fri 24 Mar 2023, 12:25

I will definitely attend on the 1st April, many thanks for organising Liz.

Fri 24 Mar 2023, 10:39

Liz,  As a scientist I dont like grand statements like ''The vast majority have D, E & F ratings' without evidence or a reference to the data, please can you back up this statement?

Fri 24 Mar 2023, 10:20 (last edited on Fri 24 Mar 2023, 10:34)

Sounds very interesting – but you haven't told us when/where! But I've tracked it down: https://www.charlbury.info/events/8513

(PS re Suzanne's Radio 2 link – the relevant bit is between 33 and 43 minutes into the show.)

Fri 24 Mar 2023, 09:26

Naming no names (to whet your appetites!), one of the Open Homes is 100m2, has a heat pump, and uses 4,000kWh/year.  It can be done and done effectively.  Come along and learn.

Fri 24 Mar 2023, 08:44

https://www.bbc.co.uk/programmes/m001jlnk

BBC Radio 2  8th March - Jeremy Vine .  Debating the effectiveness of heat pumps.

( I’ve sent link hopefully works, but if searching main title Dog attacks and Eurovision scams) 

14days left to listen I believe.  Certainly worth trying to catch up on. 

Fri 24 Mar 2023, 08:15

Heat pumps can work in houses that are very well insulated, but unfortunately they are rare in the UK. Builders don't seem to have the skills for this, and neither do the people who write building regs, nor building inspectors. Houses build before central heating i.e. 1980s or so were built deliberately draughty so that fireplaces could get oxygen and carbon monoxide not left lingering. Likewise towngas was very poisonous and needed to be ventilated out. It is difficult to retrofit house built to that standard, but not impossible. https://www.homebuilding.co.uk/news/bosch-tells-homeowners-heat-pumps-dont-work-in-old-homes

Fri 24 Mar 2023, 07:56

... also, 'cheaper solution' and 'Heat Pump' don't often go together, unfortunately.

Fri 24 Mar 2023, 07:55

Yes, unfortunately a 'bigger pump' is not the answer. Malcolm is right, you need to fix the insulation first and retro-fit the whole heating system.

Fri 24 Mar 2023, 07:23

If only heat pumps were that simple, though: as well as the insulation Malcolm refers to, generally people will need much bigger radiators; and of course you need a water tank – anyone in a small house with a combi boiler won't have one and may not have room (let alone the cost of the plumbing). It's complicated.

Fri 24 Mar 2023, 07:12

The often obstructive attitude of the planners to some of the most basic energy efficiency measures in our town needs to be overcome to achieve this.

Fri 24 Mar 2023, 03:04

You are missing the point...

Thu 23 Mar 2023, 23:08

Install a higher output rated heat pump - one intended for a larger home - to overcome the losses in your wall construction. A much cheaper solution and less aggro than external insulation.

Thu 23 Mar 2023, 22:30

Finally a good posting re energy efficiency. 

Our fake-limestone concrete block house in The Green, for example, freezes in winter due to the appalling thermal qualities of concrete (Thank Heavens we can afford the heating, what with me being chronically ill, I'd die shortly in a cold house) and we need to persuade the Planning Authorities to allow us to externally insulate everything in, for e.g The Green, in and then paint them in pretty colours... The fake limestone blocks fool no-body that they're Cotswold stone.

We're, with our 18 year old gas boiler about to give up the ghost after a number of shoestring bodge-on repairs, are not likely to be able to adequately heat this place with the heat pump we desire WITHOUT extra *external* insulation. We already have internal insulation downstairs.

At some point - and I except here, explicitly, the historic Stone-built core of the Town being sprayed with foam and painted pretty colours - we're going to have to grasp the proverbial and other *effective* measures and do something.

What are the Planners going to do about this?

Thu 23 Mar 2023, 21:43

The vast majority have D, E & F ratings. So much improvement to be made...