Allan Joyce Architects

Allan Joyce Architects used Sefaira to present the qualitative and quantitative impact of proposed improvements to an existing 325m2 tea room which will improve interior daylight, provide more useable outdoor space and reduce EUI and cooling loads.


Bettys Tearooms overlooks 58 acres of English countryside at the Royal Horticultural Society’s Harlow Carr gardens, Harrrogate. Its predominantly glazed south west facade and glazed pyramid roof maximise views of the surroundings but also contribute to overheating and unfavourable light conditions.

Allan Joyce Architects were approached by Bettys Tearooms to propose strategies to improve the internal daylight quality — Some spaces suffered from glare and overheating whilst others received little natural light.

Project Stats

Project type: Commercial

Location: Harlow Carr, UK

Client: Royal Horticultural Society Garden, Harlow Carr

Building type / program: Cafe & Tea Room

Floor area/Occupancy: 325m2

Project stage & completion date: Design & analysis stage

Performance Baseline: As built

Performance Goal: Part L for Retrofits


Allan Joyce Architects designed a range of solutions to tackle these issues. They proposed:

  • Replacing the glazed pyramid roof with a tiled roof which would include rooflights
  • Having a retractable canopy over the terrace area to prevent perimeter glare within the space and also provide covered outdoor seating
  • Adding rooflights along the existing tiled roof to bring daylight deeper into the space

Bettys liked the proposal but were unsure of the actual impact these interventions would have on the daylight levels. Allan Joyce Architects used Sefaira’s daylight analysis to generate accurate and easily read light maps as well as 3D visualisations of the space to demonstrate the effect of their proposals.

The process started with the project architect, Toby Evison, modelling the existing building in SketchUp, running daylight analysis on specific days in the four seasons of the year. With the Sefaira results, it was possible to pinpoint the problem areas, i.e.,those that were inadequately lit areas and glare prone areas.

Screen Shot 2015-04-17 at 13.25.54

Existing Interior Conditions

L-R: Perimeter & terrace prone to glare

Existing Interior Conditions

L-R: Pyramid overlit & servery area under lit

Using Sefaira, Allan Joyce Architects were able to analyse their proposed solutions to ensure better daylight distribution across the tearoom.


Below are images of floor plan before and after installing a retractable canopy across terrace, filling in the glazed pyramid and installing skylights in the pyramid roof and servery area.

Comparative daylight analysis

Screenshots showing lux levels across the floor plate on January, March, June and September 21st before and after the improvements.

Comparative daylight analysis

Renderings of the tearoom before and after the improvements

Allan Joyce Architects used the Sefaira results to put together a report for the client that illustrated, qualitatively and quantitatively, how the proposed changes actually impacted the daylight across the space.

In addition to a well lit interior and better visual comfort, they were able to:

  • reduce EUI by 9% (from 123kWh/m2/yr to 112kWh/m2/yr)
  • reduce cooling loads by 15% (from 9333kWh/yr to 7957kWh/yr)
  • add more useable floor space (115m2) that can be accessed in any weather.

Project architect, Toby Evison, said, “We were able to demonstrate that these proposals provided a much better daylighting balance than the existing building does in its current form. Our client was very happy with the finished report which they felt gave them the right information to help guide decision making.”

About Allan Joyce Architects

Allan Joyce Architects is a multi-disciplinary practice delivering creative and environmentally conscious architecture, landscapes and interiors for over 30 years. Allan Joyce Architects are dedicated to making the design and construction process inclusive for the client, and are committed to delivering high quality, energy efficient buildings throughout the UK.