Energy and Buildings 75 (2014) 216–227 Contents lists available at ScienceDirect Energy and Buildings j ourna l ho me pa g e: www.elsevier.com/locate/enbuild The use of Passive House Planning Package to reduce energy use and CO 2 emissions in historic dwellings Francis Moran ∗ , Tom Blight, Sukumar Natarajan, Andy Shea University of Bath, Architecture & Civil Engineering, Coomb Down, Bath BA2 7AY, United Kingdom a r t i c l e i n f o Article history: Received 30 March 2013 Received in revised form 10 August 2013 Accepted 23 December 2013 Keywords: Energy use Historic buildings CO2 emissions PHPP EnerPHit PV a b s t r a c t Since historic buildings constitute 25% of the European built environment they have a role to play in delivering CO 2 emissions reduction targets along with the rest of the domestic stock. However, historic buildings have significant cultural value and were built with technologies and materials that promote fabric breathability. This demands solutions that will deliver enduring and radical energy efficiency sav- ings and emissions reduction, which while maintaining their heritage value are also capable of district wide replication. Before embarking on wide scale retrofit adaptations, affordable and accurate procedures to assess the potential for such measures to reduce CO 2 emissions are of primary importance. Some measures will have an impact on both fabric and aesthetics. It is therefore necessary to ensure that the reductions in CO 2 emissions from a set of proposed alterations are significantly higher than any actual or perceived reduction in loss of built heritage. This paper demonstrates the use of the Passive House Planning Package (PHPP) modelling tool to assess the potential for retrofit adaptation measures in three terrace dwellings in Bath, England. It compares modelled against delivered energy use and then models energy and emission reduction following the introduction of a suite of retrofit adaptations. Results indicate that PHPP can assess total electrical energy consumption but requires the use of a reduction factor to reflect accurately intermittent occupancy/heating patterns. The modelled results suggest retrofit adaptations in historic buildings could deliver energy savings and CO 2 emissions sav- ings between 55% and 83%, but only when the thermal fabric is significantly improved and the use of PV is included. PHPP provided assessments of the benefits of retrofit adaptations in historic buildings that can facilitate decision making on retrofit methodology in historic buildings that affect fabric and/or aesthetics. © 2014 Elsevier B.V. All rights reserved. 1. Introduction In Europe, historic buildings [1] account for over 25% of all build- ings [2]. The scale of the problem is large, every building in Europe will have to cut its carbon emissions by 20% by 2020 [3]. The UK government has set more challenging targets with a reduction in emissions of 34% by 2020 and 80% by 2050 [4]. This is despite the UK having the oldest building stock in Europe with almost 40% of the existing residential buildings built before 1946. This means that for every one of 25 million existing dwellings in the UK that fails to reduce its emissions by 80% another one must increase its emissions reductions by a commensurate amount. Natarajan and Levermore [5] have previously shown how diffi- cult achieving even a 60% stock-wide reduction would be. Historic ∗ Corresponding author. Tel.: +44 0773 6678586. E-mail address: fmoran@blueyonder.co.uk (F. Moran). dwellings, at 21% of existing stock, cannot side step this issue and therefore must play an equal part in the effort to reduce emissions. Since most retrofit measures affect fabric, this brings the conserva- tion of energy (and hence the reduction of emissions) into conflict with the conservation of built heritage. Research indicates that a suite of adaptations can have effects varying from 40% to 80% [6–11]. It is also evident that occupant behaviour will have a significant effect on energy use [12]. What is less clear is a suitable methodology to produce and implement radical CO 2 emissions reduction solutions that are not only effective, but prove to be both durable and non-deleterious to the buildings fabric. There is a need for a model/tool to provide in a straightforward manner, at reasonable cost, accurate and reliable assessments of the benefits of retrofit adaptations in historic build- ings. If this is accepted and trusted by stakeholders it will facilitate decision making based on empirical data. The English House Condition Survey (EHS) [13] suggests a close correlation between the age of a building and its energy 0378-7788/$ – see front matter © 2014 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.enbuild.2013.12.043