Energy Performance Certificates in Marylebone

Common property types

• Howard de Walden Estate Townhouses: The grade II listed terraced townhouses along Wimpole Street, Queen Anne Street and Welbeck Street are emblematic of the Howard de Walden Estate. Solid 9-inch brick walls, period sash windows and original floorboards mean these properties often score in the D to E band, with draught-proofing and secondary glazing among the most practical improvements available without compromising listing consent.
• Marylebone High Street Mansion Flats: The mansion blocks flanking Marylebone High Street and Thayer Street date from the late Victorian and Edwardian periods. Converted into self-contained flats, they typically have solid brick party walls and suspended timber floors. Each flat requires its own EPC, and heating system type is a key variable for ratings in these buildings.
• Georgian Conversion Flats on Devonshire Place: Devonshire Place and its immediate neighbours contain large Georgian townhouses subdivided into flats, often over five or six storeys. Assessors must account for roof access on top-floor flats and ground-floor heat loss on basement conversions, both of which affect the final rating significantly.
• New-build Apartments near Baker Street: Pockets of new residential development near Baker Street and along the A41 corridor include purpose-built flats with modern insulation standards. These typically achieve B or C ratings with gas or heat pump systems and double-glazed windows, forming a clear contrast to the surrounding period stock.

Typical EPC issues we find in Marylebone

• Solid Wall Heat Loss: The majority of Marylebone's Georgian and Victorian stock has solid brick walls with no cavity, meaning standard cavity fill is not applicable. External or internal wall insulation is possible but costly and may require listed building consent, which often means these properties remain in the D or E band.
• Listed Building Constraints on Glazing: Many Howard de Walden Estate properties are listed or within conservation areas, restricting double-glazing upgrades. Assessors record glazing type as observed and note where improvement measures are constrained by planning, ensuring the EPC reflects accurate potential ratings.
• Shared Heating in Mansion Blocks: Some Edwardian mansion blocks on Welbeck Street and Devonshire Street use communal boiler systems. Correctly identifying whether heating is communal or individual is essential for an accurate EPC, and assessors need access to plant room details or service charge breakdowns in these cases.
• Complex Split-Level Layouts: Duplex and split-level conversions are common in the larger Georgian townhouses. Measuring heat loss perimeters accurately across multiple levels requires careful on-site assessment to avoid over- or under-stating the property's energy demand.