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Case study: Reducing costs for rental accommodation.

Providing high spec flats with complete control, lowering running costs and improving comfort

  • SAP compliance
  • Thermal modelling

  • Mechanical and electrical design

  • Eco smart controls: Heating, ventilation, hot water control

  • Lighting

  • PIN code entry

  • Building Performance: maintenance and management.

Client brief

Landlord/developer looking to demolish two 1900’s terraced houses in Cardiff and rebuilt as two blocks of three flats. Each flat will be used as student accommodation. The buildings were built to a high specification with low energy requirements and minimal capital and running costs. Atamate was bought in to reduce maintenance costs, control heating, ventilation and hot water so as to improve comfort and reduce overheating problems. We worked with the client early on in the design process to come up with mechanical systems and a control solution to meet the specific criteria.

Details of installation


The building was built to a high thermal and airtightness specification. Consequently very little heating was required and it was possible to use direct electrical heating while complying with building regulations. Electrical heating was chosen to reduce the installation cost of a gas supply and a full wet heating system (avoiding costs in the region of £7k–£10K for each of the flats). 

Bathroom sink and mirror

Direct electrical heating also minimised operating costs. To further reduce the energy consumption atBOS was used to control heating in each room based on occupancy (not on a time setting) and to turn off the heating if the windows are opened. Heating is provided through infrared panels and conventional electrical radiators.


Control of lighting for all communal areas and flats. Lighting is linked to occupancy to ensure minimum energy consumption. Occupation is detected using both PIR (passive infrared) combined with CO2 sensors to prevent lights turning off when rooms are still occupied.


Due to the air tight construction of the building it was necessary to provide ventilation to ensure a healthy environment whilst minimising thermal losses. This is done using DCV (demand control ventilation) on the inlet side and MEV (mechanical extract ventilation) on the outlet side.

atBOS monitors each room for CO2 and humidity build up and then opens DCV controlled trickle vents when air quality is poor. At the same time as the vents are opened the MEV is turned on to extract the dirty air.

Hot water

To minimise energy use a micro heat pump was specified and installed to heat the hot water. It extracts the heat from the ‘dirty’ air (bathrooms and kitchens) which is extracted via the MEV system. atBOS controls the heat pump to ensure there is always adequate hot water for the tenants needs.

Summer overheating

Our thermal modelling showed there was a small risk of summer overheating. atBOS uses two strategies to minimise overheating.

Firstly windows are automated, and after a hot day can be opened to create a passive stack effect; lighter warm air inside the building rises out of rooflights and the denser cold air enters through lower windows. Secondly, the output from the heat pump used for hot water provision is cold air. Atamate controls damper valves to direct this cold air back into the flats. This ensures rapid cooling.



Managing access can be time consuming and costly with multiple users. The client’s objective was to remove all keys from the building (keys can still be used as a backup). Entry to the building and flats is possible using either keypads or via remote door release from an occupants mobile.

Fewer keys are lost (midnight call outs avoided) and service calls are resolved faster as there is no need for contractors to go to the office to pick up and return keys. Finally, agents viewings can be quicker and more professional as groups are not waiting in corridors as agents find the right keys.

Phone in hand

Maintenance and Management

Building services and maintenance costs are reduced as all elements of the building are logged and reported. Issues can be resolved before they become a problem, e.g. a drop on water pressure can be rectified before residents lose hot water. All meter reading are available remotely, as are all logs of fire alarm testing.

Smart Control

Provided by atBOS. Each tenant has smart control of heating and lighting in their own flat yet do not have access the communal areas or other tenants flats.


Read more:

A guide to keeping comfortable in your low energy home

Ventilation options for an eco home 


Download our Free guide to improving energy efficiency in new build homes:

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