Case Study - Hatfield Heath in Essex

Building for the Future

Fourteen New Affordable Passive House Homes for Hatfield Heath



Project Name: Hatfield Heath Affordable Passive House scheme

Clients: Hastoe Homes Ltd.

Main Contractor: DCH Construction Ltd.

Architects Parsons & Whittley Ltd.

Building Type: 3 rows of terraced properties (13 homes for affordable rent and one for shared ownership)

Location: Broomfields, Hatfield Heath, Bishop’s Stortford, CM22 7EL

Status: Completed

Building Use: Domestic

Construction Time: Sept 2013 - Feb 2015

Budget: £1,940,948.00

Airtightness: 0.6 ACH

Passive House Certification: Achieved

Heat Load (PHPP): 14 kWh per m² of living area a year or a heating load of 9 W/m², respectively

Primary Energy Demand: 120 kWh per m² of living area and year

Energy performance Certification (EPC): B(87)

Measured energy consumption: Continuing to be monitored over the next 12 months

MVHR Products Used: Zehnder ComfoAir 200 Luxe PH

Hatfield Heath
Hatfield Heath

Overview

The Hatfield Heath project emerged after a housing needs survey prompted the local parish council to approach Hastoe Housing Association, a specialist rural housing provider, to take on the project. Hastoe is well known for its ability to provide good standards of design and construction for social housing, particularly rural exception sites and decided to use the Passive House standard for this project combined with their chosen regulations, codes and standards.

Objectives

Passive House developments are required to be energy efficient, comfortable and affordable, so it was essential that a quality heat recovery (MVHR) ventilation system was specified, enabling the properties to meet stringent energy performance criteria and achieve a comfortable all-year-round indoor climate.

Passive House Certified
ComfoAir 200 Luxe PH

Low energy solutions for the social sector

Following a suggestion from the main contractor DCH Construction that Zehnder’s Comfo Air CA200 model would be the most appropriate unit to use in the development, architects Parsons + Whittley approached Zehnder for more information and advice. With many years’ experience of working on Passive House developments, Zehnder’s experienced team understands inherently how to design suitable Passive House certified ventilation systems and were able to advise on the benefits of the CA200 as well as on its installation in the development at Hatfield Heath.

Air quality and comfort

Guaranteeing the provision of optimum quality indoor air all year round, the CA200 is designed specifically for properties up to 110m², so was an ideal choice. Furthermore, while the average MVHR unit on the market stands at between 75 and 80 per cent efficiency, Zehnder’s CA200 model offers an outstanding 92% heat exchange efficiency rate. It also has a filtered bypass, which ensures that during warmer summer months the internal environment remains comfortable. Ventilation is provided continuously without recovering the heat from extract air - which can assist with reducing summertime overheating.

COST SAVING BENEFITS

The energy consumption is going to be measured over the first 12 months following completion, but it is to be expected that as with all Passive House constructions the running costs will be markedly lower than a regular New Build, making them truly affordable for future tenants.

Hatfield Heath House

The Houses of Tomorrow

Dan Higginbotham from architects Parsons + Whittley commented
“The project was completed in January 2015 and the commissioning process went very smoothly with all dwellings passing first attempt. We believe strongly in the Passive House approach and the equipment and technical support provided by Zehnder gives us confidence in the occupants of these dwellings being fully satisfied with both comfort and energy use.”
“Ventilation is a crucial aspect of the Passive House build in ensuring both comfortable, quality air and heat efficiency so we were delighted to be partnering with MVHR Passive House experts, Zehnder. Working closely with their team, we were able to ensure that effective and efficient mechanical ventilation heat recovery solutions were provided for each style and size of property.”

His comments were echoed by Kevin Hartnett, Business Development Director at Hastoe Housing Association, who at the official opening of the new homes on 3 July 2015 by the Rt Hon Sir Alan Haselhurst, MP for Saffron Walden, thanked everyone involved in making this project a reality.

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