We always welcome feedback from visitors, but rarely get as full a review as this…
I am in the Oil Industry and a pilot neither, I admit, the greenest of occupations. My Wife and I faced a major renovation and it seemed sensible to come to listen and learn.
What did I learn?
-A Hockerton house is not a ‘magic’ house.
-Don’t stick a B&Q windmill on top of your house
-It is highly unlikely many of us could achieve what Hockerton has, but, we can all do something.
-the first step is to insulate, don’t waste energy.
-use ‘airlocks’
What do I know?
-conventional energy cost are going to rise.
-If I had the last barrel of crude oil in the world , I would not just burn it.
-If we don’t do something about carbon, its going to get hot and whilst it probably won’t affect conceited (very lucky) little me it is going to hurt those most in need. Millions of them.
-There are positive things we can do and very simple behaviours we can adopt that help; just that little bit.
So what did we do?
-Insulate! Get the house up to modern standards and prevent the energy haemorrhage.
-Build ‘airlocks’ and adopt the rule of Arctic living; we don’t open one airlock door until we have closed the other.
-Underfloor heat. Small delta T over a very large area is very efficient. Reduce to a minimum heating in areas not in use. [Here delta T is the temperature difference across two surfaces, how does it work]
-Build a conservatory to capture the heat from the sun. Isolate it in Winter or when there is no sun.
-Install GSHP: We yet to have long term use stats but advertised efficiency of 1:4 seems common sense. (Although at HHP our experience has not been so good, find out here.
-install a modern woodburner and have it ‘shared’ between two rooms by a little clever design. How can something so simple be so efficient?
-configure the kitchen to make the most of recycling so that it overcomes lazy human nature
-install a quooker; ie boil exactly what you use. No waste. (again…not sure of the stats over the long term but we will see)
-compost, harvest rainwater , grow our own and keep chickens. In terms of cost time and effort , no it is not effective but, it is a pleasure, tastes great (eggs and food, not the compost) and helps just that little bit.
-develop a ‘stingey’ attitude and aim to use and re-use everything. After a short while it becomes a habit.
In conclusion:
A visit to Hockerton is inspirational and motivational. We are doing a little bit as a result.
The tenants of one house have now been back in their home for 2 weeks, and we’ve taken a look at their energy use over that period.
Their total energy consumption is averaging at 11.93kWh/day. At that rate, their annual consumption will be 4,356kWh. However, the heaters are on at the moment – averaging 2.27kWh/day (pretty low!) – so we’re hoping the annual use will be lower than this, as these will not be on all year. It will also probably require more heating this winter as the house has been a building site for 6 months, and not able to build up a store of solar energy from the summer.
So how does this compare to their previous energy use? Well, looking at 18 months of bills prior to the retrofit, they were averaging 3,241kWh/yr of electricity and 18,972kWh/yr of gas.
So down from an annual energy consumption of 22,213kWh to 4,356kWh – not a bad start; long may it continue …
We have now completed the retrofit of the houses, and hopefully you’ll agree they’re looking great.
Front of the completed properties
The rear of the completed properties
The existing tenants of number 30, Mr & Mrs Morton, have already moved back in and are enjoying their new home. Newark and Sherwood Homes are advertising for tenants for number 28, which was previously void.
The houses will now be monitored for 2 years to see how they really perform. The monitoring includes:
- Temperature and relative humidity in 3 rooms of the house (sitting room, bedroom 1 & bedroom 2)
- External temperature
- CO2 level in the sitting room
- Total water and electricity consumption
- Electricity consumption on 8 individual sub-circuits
All this data is being monitored automatically and transmitted to a central database at 5 minute intervals, and we can view it real-time via a website.
We are also hoping to do additional monitoring on the properties, and are in discussion with a couple of universities about the possibiliity of collaborating on this.
Meters, meters and more meters!
We hope you’ve enjoyed our blog so far, and watch this space for more news of post occupancy evaluation …
The generally recommeded level of loft insulation, and that provided in most new build houses today, is 250-300mm. The houses already had about 250mm of insulation in the loft, but we have topped that up to between 600-700mm. In addition, we have then sealed the loft hatch so that occupants cannot then compact the insulation by storing lots of belongings on top of it; if loft insulation is compacted, a lot of the benefit of the insulation is lost – it restricts heat transfer because of the air pockets within the fibres.
Significant levels of insulation in the loft
Although there is no access to the loft, the houses now additional storage areas in the sun space and porch.
Insulated thermal store
The hot water in the houses is provided by a super-insulated thermal store heated with an electric immersion heater. A thermal store is like a traditional hot water cylinder, but the key difference is that the hot water in the cylinder is not the hot water used, instead it simply acts as a heat storage mechanism, hence the term thermal store. The hot water delivered to taps and showers, is actually cold water directly from the mains supply, which is then passed through a large copper coil (heat exchanger) within the thermal store, and in doing so extracts energy from the hot water in the store to heat it. As the water in the cylinder is not being used directly, it does not need to be heated to 60 degrees to kill legionella bacteria; instead it can be kept at aorund 45 degrees, significantly reducing energy consumption. The hot water delivered is around 40 degrees, more than adequate for washing and showering.
Super insulated thermal store - it is in there, honest!
