Code for Unsustainable Homes

I’ve been looking at options for sustainable housing recently following a raft of competitions for housing associations who want to achieve Level 5 of the Code for Sustainable Homes. Level 5 requires zero carbon emissions from heating lighting and ventilation, so you have 2 options; install a conventional boiler and enough extra PV to offset the carbon or install a biofuel boiler. Since PV is vastly expensive, this really only leaves the biofuel boiler.

Now, we can design well insulated housing these days with peak heating loads well below 5kW. However, can you find a fully automatic  woodfuel boiler below about 15kW in output? No – at these low loads the only option seems to be manually fuelled room heaters. Wood boilers really need to be fired at full power for a reasonable period to avoid problems with tarring up. In other words the smallest automatic boiler is sufficient for 3-4 homes at CSH Level 5 or 6. This is great if you are a housing association and can install common plant and distribution, but what about developing housing for private sale, or even single properties.

The Government insists that all new housing shall be CSH Level 6 by 2016. So, if you are building a single house and don’t fancy inconvenient manual fuelling, you’d be better off not insulating the house at all in order to create sufficient load for long term reliable operation of your woodfuel boiler After all, the fuel is carbon neutral so you get all the credit even if your consumption is excessive. How stupid is that?

I think that this is another example of legislators adopting a voluntary code and forcing it on the market without ever considering the implications.

5 thoughts on “Code for Unsustainable Homes

  1. Sorry, Doug, I do not agree. Of course there are boilers that can cope with ultra low consumption figures – it just needs a bit more thinking and an intelligent system (even based on wood fuel).

    However, I have not seen one building really achieving that 5kW/m²a at all (in the UK) because there is a huge difference between the theoretical values and what is really built.


  2. It’s harder to figure out than that. If the October update comes in as consulted on, Code 5 and 6 homes will be limited to 39 kWh/m2/yr for mid-terrace homes and flats and 46 kWh/m2/yr for detached and end-terraces.

    So the house will have to be well insulated, but you’ll still be unlikely to have enough load for your biomass boiler.

    • Thank you Jamie – that’s precisely my point; energy efficiency is the correct route to follow. Forcing the adoption of inappropriate small scale renewables through legislation is misguided and likely to lead to unexpected consequences.

  3. It is even worse than that!

    Sadly I think the Code is too broken to fix as the whole concept is wrong with arbitrary system boundaries drawn depending on technology.

    Article to follow soon.

    Keep up the good work.

    • Nick

      I don’t necessarily agree that the Code is broken.

      I wholeheartedly endorse CSH, BREEAM, LEED, Greenstar and the others as a means to generate continuous improvement in the industry. However, there is a vast difference between writing an aspirational guide such as these, and legislation such as the Building Regulations. The problem occurs with lazy legislation subverting these voluntary systems with no consideration of the consequences.

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