Building's resident regulations expert logs on to 'fantasy Part L' website and, after a few attempts, manages to build a virtual house that complies with everybody's favourite Building Reg. It's just a shame it doesn't have any windows ...

Full marks to the NHER and Construction Products Association for trying to instil a sense of fun into the tedius business of implementing Building Regulations.

The two bodies have launched a website with the friendly moniker which allows builders to quickly ascertain whether their homes meet Part L. Simply choose whether you want to build a four-bed house or two-bed flat and stick in the U-values, air leakage rates, and a few other details and ta da, up pops the verdict. Pass if you've been holistic and covered all the (insulated) angles, but Fail if you're still obsessed with U-values and forgotten the other energy saving bits.

The website's handy carbon dioxide calculator produces a dwelling emission rate for your design, which can be compared with the Part L Target Emission Rate (24.28, in case you've forgotten).

Having only previously built in plasticine and Lego I was quite pleased with my first ever attempt at Part L compliance. After some tweaking of the dials I managed to hit the target, primarily by bricking up the windows and slapping some solar panels on the roof. Of course my home will be sited in a planning utopia where the installation of PVs raises no hackles among council conservation officers.

Unfortunately, the programme also doesn't tell you how much your solution might cost. But that's the fun bit isn't it? Until they invent a programme that integrates energy performance, specification options and whole life costing you'll still be fiddling with the abacus. may not be the approved Part L calculation software (there's only one version for a start), but it does offer a fun way of familiarising yourself with the principles behind new Part L. For those ready to graduate to the real thing BRE announced today that it had released a new version of Simplified Building Energy Model for compliance for buildings other than dwellings.

The BRE claims the new version includes a simpler way of entering data for the whole building, and a wider range of weather locations (locusts, frogs, blood?!). Any software development less likely to give you a Part L-induced migraine is fine by me.