Some Frequently Asked Questions...
What would be the expected CO2 emission reductions in a Touchwood house relative to a standard house?
The idea is to meet the Passivhaus standard, which aims to reach a 90% reduction in heating demand through minimising heat loss through the building structure. We then aim to supply the remaining 10% either through solar gain, a small heater in the HRV system, or a log stove. Log stoves produce 96% less CO2 than gas, and wood pellets 93%. This massive saving is due to wood having no net change in global CO2 concentrations since the CO2 released was only absorbed by the tree recently. The small perecentage emitted is due to the processing / transportation of the fuel.
It follows from this, that we achieve a 90% saving on demand and then a 93% saving on supply, so a 99% reduction on CO2 emissions overall. Note this is for heating.
For hot water provisions we recommend a large solar panel for the summer, followed by a low carbon option for winter - such as pellets, log boilers or similar - if the location allows. The solar would provide around 55% of demand, with pellets / logs providing the remaining 45%. CO2 wise this would provide a reduction of around 96%, with the added benefit of your fuel bills stimulated a local wood fuel market - rather than your money leaving the country to fund an oil company.
How much money would I save?
Your heating demand should be reduced by 90%, with some clients reporting no need at all for heating - the heat provided by solar gain, appliance and body heat being enough to maintain a comfortable temperature.
Your hot water should be 55% from solar so nearly free (bar small electric circulation pump & controls), with remainder by pellets / logs with a comparable cost to conventional fuels (with the cost of logs/pellets dropping as supply increases, and oil increasing), so a 55% saving.
What are the advantages of using timber frame for my new home?
The house can be very energy efficient and save money on running costs. The structure is completely sustainable and is a carbon sink mechanism. The timber frame comes in one lorry, complete with triple glazed windows and doors, so no complications trying to source quality products that go together. It is quick to erect, usually it will take only a couple of weeks, depending on the size of the building and how many people are working on its erection. Our timber frames have 300mm thick walls (far better than building regulations requirements) which makes for a super insulated structure with low running costs.
Will the house be fire resistant?
Our timber frames are filled with Warmcel 500 made from fire proofed recycled newspaper which is completely fire resistant. Timber is engineered to allow for a 'charring factor'.
Is timber strong enough to build a house from, and will it last long?
People have been using timber frames for building houses and ships in England since mediaeval times and many of them are still around.
What are the benefits to the environment if we use timber frame?
Timber is a renewable resource constantly growing soaking up carbon dioxide. The number of trees is increasing because more are planted than are cut down. The energy used to convert the tree to a timber house is very low especially when compared to bricks
What design restrictions are there with timber?
Timber frame houses can come in any shape or form the only restriction is your imagination
How much would the frame be for a two bedroom house?
As a ball park figure, £42k would be a basic price but it would depend very much on your design.
How much will it cost to heat my Passivhaus home?
A well constructed Passivhaus home will have excellent airtightness (<1.0), insulation, and minimal cold bridging. As such the heating demand will be < 15kWh/m2/yr (that's per m2 floor area). This minimal heat requirement can then mainly be met through solar gain and heat produced by appliances, cooking and body heat. To put this in perspective, one of our recently completed homes (early Jan. 09) has still had no need for the heating system to be installed. This is because so little heat is lost through the building fabric due to the air-tight construction and super insulation. Once constructed to this level solar gain through the south facing glass and heat provided by appliances and the occupants is sufficient to maintain a comfortable internal temperature.
How much power would a wind turbine produce?
A turbine in a good location in Southern England would have a capacity factor of around 10%, meaning a 5kW turbine would produce 5kW 10% of the time. So a 5kWp turbine would produce around 5 x 24 x 365 x 0.10 = 4400kWh / year. These figures are conservative and the south east has a low average wind speed compared to other areas of the UK, so in a good location you should produce significantly more. Roof mounted turbines can be ruled out since anything large enough to produce a meaningful amount of power would not be fixable to an existing structure without major structural work.