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Transforming homes for over 40 years...

Fully Qualified Retrofitting and Domestic Energy Assessments in North Yorkshire.

Brick Wall

Who Are We?

Quandong is a retrofit and energy assessor with over 40 years of experience in the construction industry. 


Fully accredited in domestic energy and retrofit assessments, we specialise in improving your property's energy efficiency, structural quality and defences from mould, damp, condensation and more... 

About Us

Why Choose Us?

40+ Years Experience

Knowledge and experience gained through 40 years in the construction industry operating in a wide variety of roles.

Trusted Partner

We've worked with the CITB for many years, were previously Vice Chair of the North Yorkshire Construction Training Group, and are an Enterprise Adviser working with North Yorkshire Schools through NYBEP.

In-Depth Reporting

Our reporting can help to achieve a full house retrofit when working with Retrofit Coordinators and Designers. We'll help you claim grants where available and increase the value of your property.


We identify improvements and solutions to look after tenants and householders, improve Energy Performance Ratings (EPC’s) and plan for future projects.

What is Retrofitting?

Retrofitting is the process of carrying out changes to existing homes and buildings to improve energy consumption, reduce emissions and by extension - reduce fuel bills.

The scale of such a process is dependant on the age of a building, its current state of repair, level of current insulation as well as systems already in place to prevent such things as mould and damp ingress.


Domestic Energy Assessments

An energy assessment is required whenever a building in the UK is built, sold or let; it must be completed by a qualified and accredited Energy Assessor.


The assessment itself will typically take into account:

  • The building age and dimensions,

  • The fabric (walls, floors roofs, doors, etc)

  • Information about the services used to generate heating, lighting and hot water

Using flagship software and technical support, we provide highly accurate assessments carried out by trained professionals.

PAS 2035 & Trustmark

What is PAS 2035?

PAS 2035:2019 was sponsored by the UK Government's Department for Business, Energy and Industrial Strategy (BEIS). This is the key document in a framework of new and existing standards on how to conduct effective energy retrofits of existing buildings, it covers how to access dwellings for retrofit, identify improvement options, design and specify Energy Efficiency Measures (EEM) and monitor retrofit projects.

The standard drives the 'whole house approach' including the 'fabric first' methodology. It defines the qualifications and responsibilities of individual retrofit roles and respective activities required prior to and post EEM installation.  It also includes a risk assessment process that builds incrementally robust requirements depending on what requirement path (A, B, or C) the retrofit project is assessed to fall within.

It is not possible to be certified to PAS 2035:2019 in the way that it is with PAS:2030. In the case of PAS 2035:2019. TrustMark Registered Businesses carrying out work within its scope are required to be compliant with its requirements; subject to the transition arrangements outlined below.

PAS 2035 is inextricably linked to PAS 2030:2019, the new industry specification to replace PAS 2030:2017 and is the standard to which all energy efficiency installers must be certified and compliant.

About Trustmark


TrustMark is a UK Government-endorsed enterprise scheme that acts as a regulator to ensure the highest quality of work is being carried out inside and outside your home. 

Trustmark is responsible for driving construction standards up and improving the protections for homeowners.

Trustmark ensures that when you select a business to undertake any work on your home, they're of the highest standard in training and qualifications.

We're proud to be among 15,000 tradespeople registered with Trustmark as it means the work we carry out and the standards we perpetuate are of the highest quality and confidence. 

Our Trustmark License Number: #3164143

Our Partners


Addressing Your Needs


How efficient is your property?

Is it more expensive to heat than it could be?

What repairs or improvements are required to make it more energy efficient?

What is practical, affordable, achievable?

Quotes and Costings

The cost of an assessment will vary depending on the type, condition and size of the property. We strive to offer the most accurate quotations so once you get in touch using the form below, we'll arrange a follow-up phone call to learn more about the property, conservation areas and listings. From there, a quote and visitation will be organised. 

An indicative charge for an average 1960’s 3 bedroomed semi-detached house would be approximately £200. 


Yorkshire-born, Yorkshire-based

Our primary catchment area is North Yorkshire, conducting surveys for clients across the region.

If you're located outside of our North Yorkshire catchment area, an additional distance charge may be incurred for surveying services. If you'd like to learn more, use the contact form below... 

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