Significant energy and carbon originate in the existing built environment and retrofit is therefore a key carbon reduction strategy. However heritage buildings -comprising around 20% of UK buildings-are challenging to retrofit appropriately due to their historical values and traditional construction. Retrofit carbon savings are dependent on current energy use which is strongly influenced by residents' behaviours, and retrofit decisions for domestic heritage are generally the responsibility of homeowners. Therefore both residents' views and behaviours are important for effective retrofit strategies. However behaviours are rarely considered in standard energy models and residents' views are often overlooked in heritage retrofit policy. This paper analyses a survey of the views, values and behaviours of 147 residents of pre-1940 buildings. The majority are found to strongly value their homes' heritage and mainly view exterior building alterations negatively. However residents' heritage values and acceptable retrofits, frequently differ from those of experts and policy makers. Residents report actively engaging in several positive energy behaviours and many have already undertaken common carbon saving measures. These findings imply that, for effective carbon reduction from heritage buildings, policy and legislation needs to extend beyond current definitions of 'heritage' and acknowledge residents' complex values, motivations and energy behaviours.