February 2009

ecolectrictoasterNot electricity-free, but apparently 34% less electricity than other toasters – not a bad start!

Made by Morphy Richards, it seems to be available almost everywhere for around £34-35. You can get one from the Good Energy shop, which would seem to be an ethical way to buy.

solarthermal-300x225This sounds a bit too strange to be true, but it does appear to be above board. I’ve emailed them to check and we’ll see what the response is. 

Anyway, what am I talking about? Good Energy – suppliers of 100% renewable electricity – are just starting to roll-out a Renewable Heat Incentive. On this programme they will pay you 4.5p per kWh you produce. Don’t worry, you do not need to work out a clever way to trasport the hot water back to Good Energy – you can keep using the hot water, your bank account just gets an additional warm glow too.

Steadily firming up the shopping list for our new house – here’s the latest list, with links. 


Dining Room

  • Expandable table


  • Instant-heat to stand in front of (Gas?)


  • Wood-fired stove
  • Central Pendant light in diffusing shade – 12v CFL?
  • Two Standard/Reading Lamps – 12v CFL?


  • Kitchen Scraps Compost: Black Soldier Fly Composter / Worm Farm 
  • Firewood store, and at least 12m³ of wood
  • Greenhouse with Aquaponics system

Heating & Hot Water

Power & Light


Having been looking at increasing our resilience and reducing our impact by using rainwater internally from a large Rainwater Tank, one thing to note is that it can also save us money. Firstly we need to get a meter fitted, so that we’ll only pay our standing charge plus actual water usage. If we’re not using any external water then, according to United Utilities’ Rate Sheet we could be paying as little as £43 a year – saving about £100 a year. Secondly we can apply for a reduction in our Sewerage charges as the water will no longer be entering the sewer. It’s not a huge reduction  – about £34 a year on the fixed charge, plus about £100 a year on consumption charges, but better than nothing! 

So in total we’ll probably save just over £200 a year – not enought o make it a no-brainer investment decision, but certainly a nice bonus for something we were already wanting to do.

esse100seThis is something we need to work out – our new house will be in a smoke control area. To check whether you’re in a smoke control area look up your local authority here. If you are then the only wood or multi-fuel burning stoves you can fit are listed on the exempt appliances list. It also explains what types of fuel you’re allowed to burn in them.

There is a good collection of the usual suspects – Clearview models, the Dunsley Yorkshire range, several Rayburns and Morsos. And some I haven’t looked at before – Dovre, Hwam, some Stovax models, and Westfire. Stoves Online have a great list of their clean-burning stoves, with links to piccies and details

In a surprise, Esse do not have any models on the list, but a quick check of their site shows that they have just launched (9th Feb) a new model that is OK in smoke-free zones. It’s the compact 100SE model – as shown in the photo!

grafcarat6500lAs promised in my previous post about drinking water, here are my thoughts on our rainwater storage.  In our current home town of Brisbane, Australia, the dams that supply our drinking water recently bottomed out at around 14% capacity. The severe water restrictions that we’ve had for years have meant that even in our inner-city suburb about half the houses have rainwater tanks, as without them you are effectively not allowed to water your garden. These aren’t your British-style 200 litre water-butt either. Hardly any would be less than 3000 litres, most would be 5000 litres, and quite a few have 10,000 litres. We’ve currently got two 3000 litre tanks, plumbed into to an underground weeper hose that runs through all the garden beds, controlled by a programmable timer that runs the two watering circuits on alternate days. This has ensured that we have kept our lush tropical garden alive through a seven year drought.

What it doesn’t do is supply any water to the inside of the house. For a while we did use it for our washing machine (a separate tap that we connected the cold water hose to) but as this required a manual changeover it only happened rarely.

To peak-oil-proof our water supply I want our UK system to be fully plumbed in to the house and able to supply our basic, emergency  requirements, and ideally all our requirements. I’m going to try to do this relatively scientifically – based on the Tank Size Calculator from RainWater Harvesting. Manchester provides a very different scenario to our Brisbane rainfall – there’s 400mm less a year for a start, and it is more evenly spread thoughout the year, minimising the need for a huge tank to cope with peaks and troughs.

With our roof area (about 100m2) and Manchester’s annual rainfall (806mm) we can expect to collect around 64,500 litres/year (at 80% efficiency). That sounds like a huge amount, but when you consider that our current water consumption is around 250 litres a day, we currently use 91,250 litres/year! So to be self sufficient in water with our current roof size we’ll need to reduce our in-home water consumption by around 30% – that looks like the subject of another post!

So what size tank do we need to make sure that we collect as much water as we can, without wasting any? I concocted my own monthly water use chart, based on meeting a target of 170 litres/day (then found out that there’s a very good one in the RanWater Harvesting spreadsheet!).  From looking at this (below) I’ll have a shortfall of 3000 litres in the first year – so in this table I’ve pre-filled the tanks with 3000 litres to ensure that they don’t drop below zero. In reality this “top up” would happen in stages during the year depending on our actual daily consumption to give us the chance to be extra-economical as the levels drop. 

  Rainfall /mm Water Collected /litres Available Litres
Water Used
(170 l/day)
Storage at Start   & End of      Month
Jan 71.5    5,720 184.5     5,270 450  3,000     3,450
Feb 51.8    4,144 148.0     4,760 -616  3,450     2,834
Mar 64    5,120 165.2     5,270 -150  2,834     2,684
Apr 49.1    3,928 130.9     5,100 -1172  2,684     1,512
May 53.8    4,304 138.8     5,270 -966  1,512       546
Jun 66.8    5,344 178.1     5,100 244     546       790
Jul 59.5    4,760 153.5     5,270 -510     790       280
Aug 70.9    5,672 183.0     5,270 402     280       682
Sep 69.9    5,592 147.2     5,100 492     682     1,174
Oct 86    6,880 221.9     5,270    1,610  1,174     2,784
Nov 81.9    6,552 211.4     5,100    1,452  2,784     4,236
Dec 81.4    6,512 210.1     5,270    1,242  4,236     5,478
Year 806.6  64,528 176.8   62,050   2,478    

In this our water storage peaks at around 5,500 litres, so unless we manage to keep at or below our tight 170l/day target for several years there is limited benefit to installing a tank any larger than 6,000 litres

Tank Suppliers


In my PassivHaus Renovation post I said that:

Any non-solar water heating to be Gas Condensing boiler or CHP – wood fired stoves are not permitted (this conflicts with my peak-oil resilience planning)

In return I got a comment posted by Andy Simmonds at the AECB stating:

The AECB standards do not proscribe wood stoves, nor does the german version of the PassivHaus standard.

I’ve been back to the AECB standards and here are the sections of the Proscriptive Standard that deal with heating & cooking:

Space heating (Silver Standard):

Normally radiators or underfloor pipes. Fed from SEDBUK A-rated mains gas condensing boiler, CHP or, outside the gas supply area, SEDBUK A-rated LPG or oil condensing boiler, earth-source heat pump (seasonal COP ≥3.0) or cleanburning biomass boiler; i.e, one using liquid or gaseous fuels. Wood pellet boilers are permitted outside the gas supply area but are not encouraged due to the exhaust emissions. Blocks of flats or maisonettes to have a central boiler and/or CHP plant or heat mains connection; i.e. heat distribution within the block rather than individual boilers or electric heating.

Space heating (Gold Standard):

Normally hot water coil(s) in ventilation ductwork. Circulating pump consumption ≤0.1 W per m2 floor area or pro rata; e.g., Grundfos Alpha Pro or equiv. Heat sources as for Silver.

Cooking (Gold Standard):

Hobs gas, LPG, electric induction or clean-burning biomass – liquids or gases only. Ovens gas, LPG or electric A-rated. Electric min. A+ or A++

I don’t see anything in there which suggests a wood-burner would be permitted? I’ll have a chat to Andy and see if he can clarify things for me!

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