This is a summary of how zero carbon house avoids using fossil fuels and saves energy. (For more detail, see the design section of this site and the technical menu.) The use of fossil fuels is avoided through:
- super insulation of the walls, roof, doors and windows
- airtight construction (warm air leaks out through ordinary walls)
- heat-exchanging ventilation (fresh air coming into the house in winter is pre-warmed with waste heat recovered from the stale air going out)
- natural ventilation in summer (opening windows and rooflights to ventilate)
- making the most of daylight (to minimise the use of electric light)
- using the warmth of the sun to warm the house (most of the windows receive direct sunlight)
- storing the sun’s heat in the heavy construction of the walls and floor
- using solar thermal panels on the roof to heat water which is stored in a specially insulated hot water cylinder
- using photovoltaic panels on the roof to generate electricity. What is not used in zero carbon house is exported to the national grid and used by the school over the road. When it’s dark, electricity is imported. In effect, the National Grid is used as a battery – zero carbon house puts into it about 150 per cent of what is taken out
- using the most efficient electrical appliances available
- growing firewood in the garden to burn in a wood burning stove in the house. Wood is a renewable fuel, not a fossil fuel. The house only needs supplementary heat during the coldest six weeks of the year. As the trees grow back, they re-absorb the CO2 that is released from the flue, making the wood effectively carbon neutral as a fuel source.
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Hi Nigel Lloyd
That sounds really impressive and I love the name ACOCKS GREENER!
If you have a website or link I’d be very pleased to put it on Twitter?
In response to your query, these are my first thoughts:
1. You will have greatly reduced your home’s heating load/heat loss.
2. As you already have PV & a battery, much of the electricity you’re using will be renewable – and as the grid decarbonises, which it’s doing at an increasingly rate now, better than had been expected, any electricity you need to import will be progressively greener.
4. I guess with your solar PV you may have no roof space left for solar hot water panels? – but if you do, they are sometimes overlooked as “Cinderella” of renewables… Although they wouldn’t provide all the heat you need for space heating & hot water the whole year around, they would certainly reduce your requirement.
4. So building on 1&2, with or without 3 above, I suggest you might consider a ground source heat pump or an air source heat pump in place of your fossil-fuel gas boiler for your remaining heating/hot water load? There is still a government incentive scheme for these…
Best wishes
You might be interested in our home. We have a 1958 end-terrace council house in Acocks Green which we have ‘improved’:
– added 10cm rock wool external wall insulation in addition to existing cavity wall insulation.
– installed MVHR
– converted loft into heavily insulated bedroom + ensuite bathroom with wall of N-facing window
– replaced floor slab (had to because red ash had been used as hardcore and floor had popped) and installed underfloor insulation and wet heating
– placed PV panels on S-facing pitched roof and ‘flat’ roof and installed battery.
Now we would like to eliminate gas for hot water (washing, radiators in upstairs rooms). Any ideas?
We are also forming ‘Acocks Greener’ to mobilise the community to respond to (and prevent) climate change, leading the change for Birmingham.
I cannot find the address to see if it is viable to come to visit?
Please may I ask type of woodburner is used?
Please may I ask what kind of woodburner is used??
Yes, it is an excellent product, see http://www.ecoflap.co.uk/
Our letterbox is triple-sealed. It consists of an outer brass flap (not airtight, but hard-wearing and matching our reclaimed brass door hanles), then the Ecoflap inside (very good airtightness). Letters go into an internal compartment with a further air-sealed internal door.
I see on the Ecoflap site that you used their letterplate for draught exclusion, but it is not mentioned here. Did you find it useful?
Its a heat store of 1000 litres, ie about 5x a normal domestic cylinder. Our solar panels on the roof will fill the tank with hot water. The large size of the store is so that even in winter on frosty/sunny days we hope to get a reasonable input, which will tide us over if we then get a number of cloudy days. Its been put together by GreenShop Solar http://www.greenshopsolar.co.uk/
The ventilation system is mechanical ventilation heat recovery as used in German Passivhaus design and is made by Itho http://www.itho.co.uk/Products/HRU_ECO_4/Default.aspx?id=19
System designed by The Green Building Store http://www.greenbuildingstore.co.uk/ but we have added a special heater battery so the solar store can add heat into the mvhr if required
Are you using the heated water directly or are you using the heat store principle?
What ventilation system are you using?