Our ultimate eco home will hopefully contain the highest standard of eco features; what is achievable on our small site (and has been added as a planning condition by the council) is to meet Code for Sustainable Homes Level 4.
Whilst on the face of it this may not sound too difficult (most of the building fabric and specification of materials will meet the required levels) and by 2016 we are all required to then meet Code 6!
The challenge appears to be the other areas where we must also pick up points. These include ‘lifetime homes’ and ‘secured by design’ as two key examples.
What we hadn’t anticipated was the cost involved in achieving this score – the incremental cost to our build is still being finalised but should not be substantial. What was a surprise are the professional fees for a certified person to prepare reports, validate our progress etc. We are sitting on an initial invoice of over £3000! After meeting with him we realise the extent of the work involved and all the various compliance required to meet this requirement.
We are actually glad we don’t need to do it all ourselves really – he will spoon feed us along the way with what we need to prepare for, (to ensure we don’t miss something that should have been done earlier and it could then be too late!) to comply with what we must complete and when we need to do it.
Our expected score is a total of 69 points which gives us Code 4 (total points required is 68) so we only just scrape in!
When we first discussed the approach in reaching Code 4 with our consultant, based on the house design at that time, his response was:
‘You are still a long way off from achieving Code 4.
To achieve sufficient credits you would need to also have:
* Site Waste Management Plan with more than 85% of construction waste diverted from landfill.
* Achieve the Security credits (consultation with police, follow their recommendations etc.)
* Have an ecological survey conducted and implement ecological enhancements
And even then that only just gets Code 4 – very little room for manoeuvre.’
The main challenge with our single storey structure is the difficulty in heating the space due to the internal volume of the building compared with external wall ratio.
This means we are effectively limited in accessing further points in relation to Energy & CO2 Emissions, where we only score a meager 5 out of total of 10 points on Dwelling Emission Rate and 3.2 out of 9 on Fabric Energy Efficiency, which is a costly 11 points, when we don’t have that many to play with.
We were constrained in our planning application to make this property a single storey but he advises smaller footprint and multiple storey is a far better approach if possible.
In regards to our approach now the only areas where we have options is as per his candid view below:
‘There is some flexibility as you could avoid Secured by Design now as long as you have a Site Waste Management Plan with 50% of waste being diverted from landfill. Alternatively – achieve Secured by Design and you can avoid the Site Waste Management Plan completely. Alternatively, avoid both by putting 3 more PV panels on the roof.’
The below list shows the areas and specific approach for our site that we need to follow (in simple design terms) in order to achieve Code 4:
• Build using SIPs panels as described. Floor u-value 0.15. Doors and windows u-value 1.2, Skylights 1.4. Baxi Neta-tec combi boiler, programmer, room stat, TRVs, weather compensator. 1.2kWp PV panels on roof. Air permeability 5.0 (much lower and you need a mechanical ventilation/heat recovery unit – then would need permeability to be less than 3.0)
• Energy Display Device (free if get gas and electricity supply with SMART meters from Eon or British Gas)
• Drying line in garden – minimum 4m
• Fridge freezer A+ rated, dishwasher and washing machine A rated
• All external lighting energy efficient with PIR, daylight sensors
• Secure cycle storage for 2 cycles.
• Facilities for Home Office in one bedroom (electrical sockets, telephone point)
• Low flow/use water fittings (taps, shower, WCs, bath)
• External water butt.
• Compost bin in garden.
• Recycling bin – 30Litres size fixed in kitchen cupboard.
• Site Waste management plan – all waste needs to be sorted off-site by waste contractor and more than 50% recycled/reused and report provided.
• Soil report and calculations
• Soil infiltration test
• Permeable paving to front as not draining to soakaway.
Health and Well-being
• Lifetime Homes – all door thresholds level as well as other items described in help guide.
• Record water, electricity and diesel use on site during construction
• Secured by Design – follow the police CPDA recommendations and meet Secured by Design standards
This is going to be quite the learning curve…!