Case Studies
Warwickshire House
Remit
The clients live in a beautiful 18th / 19th century house with many extensions. The property is in a village location and conservation area. The remit was to investigate the potential for a wind turbine as the client's electricity bill was over £140 per month.
WW carried out a full energy audit and found that high electricity bill was due to 3 main factors; a granny-type annex that was all electric, underfloor electric heating to the conservatory and a dehumidifier to dry out a cellar.
In addition we found that the central heating was driven by an old propane boiler and that the heating bill was in excess of £3,000 p.a.
In other respects the client's were very energy conscious having installed low energy lighting, increased insulation and replaced fridge, washing machine etc. with high efficiency appliances.
Solution
- Increase the insulation still further.
- Install a solar hot water panel and thermal store in the granny-annex.
- Replace the gas boiler with a wood pellet boiler.
- Switch off the dehumidifier as it was having no effect.
Capital Cost
- £6,500 to replace the gas boiler with a pellet boiler
- £4,500 to install solar hot water panel and thermal store
NET BENEFIT
- Electricity bill reduced by around 30%
- Heating bill down from £3,000 to £700 per year.
- Overall saving of £2,800 per year
- Carbon emissions reduced by over 60%
Berkshire New Build
Remit
Building a new home in a country location. although near a major conurbation the site is not overlooked by neighbours and is relatively remote with only electricity available from the mains. The remit was to design a wind turbine system as the clients had already opted for pellet boiler heating.
The survey of the property showed that a wind turbine was not viable. The property is located in a natural hollow, taking it out of the prevailing wind. It is also surrounded on 3 sides by trees meaning that the wind that reaches the property is turbulent. Any wind turbine installed would produce unacceptably low output.
The survey also showed that the property would lend itself to solar hot water panels and a geothermal heat pump. These options were investigated further and a cost comparison to wood pellet provided.
Solution
In this case a combined heat pump and solar hot water system, operating through a buffer tank would be around 20% less in terms of capital cost than a wood pellet boiler. Annual running cost would also reduce from around £600 p.a. for wood pellets to under £200 p.a.
We also recommended that the designed floor and roof insulation be increased to improve the performance.
Monmouthshire Barn Conversion
Remit
The clients are converting a barn in a rural setting, which is still at the design stage. The clients had considered renewable energy and been quoted in excess of £8,000 for solar hot water panels. They wanted to check if this was the best thing to do and if there were any other possibilities.
The site survey revealed that a solar panel was entirely feasible as the property had a large, south-facing roof. It also revealed a large pond a few metres from the property. There was insufficient land for a heat pump ground array but this pond offered an excellent alternative.
The conversion had been designed to Part L Building Regulations standard but we recommended that floor insulation be increased to 100 mm to reduce heat loss.
Solution
Install a solar panel, from a different supplier. Capital cost £4,000 Install a heat pump with a slinky array in the pond. Capital cost £6,000 Install a thermal store, connecting both of these machines. Capital Cost £1,250.
Annual running cost for heating and hot water less than £300.