Does anyone have experience of achieving Code 3 when using gas as heating fuel, but with no solar.

Job is in National Park and client is keen for gas and thermal envelope over ASHP.

I am not familiar with the various Appendix Q products either in terms of SAP results or for long-term maintenance and performance.

Any ideas?

Ta

Aren't we all building to code 3 now , with new 2010 building regs ?

Thanks for comments.

Daryl have you any experience with heat recovery systems and other appendix Q bling?

The units are already as small internally as permissible by the funders and the external walls cannot increase their footprint due to planning. So increasing wall thickness isn't a runner (they are already going for approx 0.2 u-value).

Appendix q is likely to be the salvation but there are so many products that it's hard to know which is more effective.