Frequently Asked Questions

Question 1

What is an air tightness test and why is it required?

Accepted Answer

An air tightness test — also called a blower door test — measures how much air leaks through the fabric of a building. A calibrated fan is temporarily fitted to an external door and used to pressurise or depressurise the building. The result is expressed as an air permeability figure in m³/(h·m²) at 50 Pascals. For new-build dwellings in Northern Ireland, a test is required under Part F1 of the Building Regulations to demonstrate compliance with the design air permeability target.

Question 2

How long does an air tightness test take?

Accepted Answer

The test itself typically takes around one to two hours on site, depending on the size and complexity of the building. This includes preparation — sealing intentional openings such as trickle vents and open fireplaces — the pressurisation sequence, and producing the test report. Results are available the same day.

Question 3

What happens if the building fails its air tightness test?

Accepted Answer

A fail simply means the measured air permeability is higher than the target set at design stage. In most cases this can be resolved by identifying and sealing the leakage paths — often around service penetrations, junctions, or poorly fitted membranes. A retest can then be carried out once remedial work is complete. It is far better to find and fix these issues before handover than to leave them unresolved.

Question 4

When do I need a domestic EPC?

Accepted Answer

A domestic Energy Performance Certificate is legally required whenever a residential property is sold, let, or newly constructed. Landlords must hold a valid EPC before marketing a property to let, and sellers must have one in place before a property is listed for sale. EPCs are also sometimes requested by mortgage lenders or required as part of planning or grant applications.

Question 5

How long is an EPC valid for?

Accepted Answer

An EPC is valid for ten years from the date of issue, provided no significant changes have been made to the property in the meantime. If you carry out major energy-related improvements — such as installing a new heating system, adding insulation, or fitting solar panels — it is worth commissioning a new assessment to reflect the improvements and update the rating.

Question 6

What affects an EPC rating?

Accepted Answer

The rating is calculated using the Government's Standard Assessment Procedure (SAP) methodology and takes into account factors including wall, roof, and floor insulation levels; window and door glazing; the type, age, and efficiency of the heating system and controls; hot water provision; and any renewable energy installations. The assessor collects this information during a site visit and enters it into accredited software to produce the certificate.

Question 7

How does draught detection work?

Accepted Answer

Draught detection is carried out under controlled depressurisation conditions — the same blower door setup used for air tightness testing. With the building held at a negative pressure, air leakage paths become significantly more pronounced and can be located using smoke detection or a thermal imaging camera. This makes it possible to pinpoint exactly where draughts are entering, rather than guessing.

Question 8

When is draught detection useful?

Accepted Answer

Draught detection is particularly useful for existing properties where occupants are experiencing cold spots, high heating bills, or noticeable air movement around windows, doors, floors, or ceilings. It is also a valuable diagnostic tool during a retrofit project, helping to prioritise airtightness improvements before insulation or mechanical ventilation is installed.

Question 9

What is the best time of year for a thermal imaging survey?

Accepted Answer

Thermal imaging surveys are most effective during the colder months — typically October through to March — when there is a meaningful temperature difference between inside and outside the building. A minimum delta-T of around 10°C is generally recommended for reliable results. Surveys carried out in summer or during mild weather are unlikely to reveal insulation defects or heat loss patterns clearly.

Question 10

What can a thermal imaging survey find?

Accepted Answer

A thermal imaging survey can identify a wide range of building defects and performance issues, including missing or poorly installed insulation, cold bridging at structural junctions, air leakage paths, moisture ingress, and underfloor heating faults. It is a non-invasive technique — nothing needs to be opened up or disturbed — making it a cost-effective first step before any remedial work is planned.

Question 11

What is included in the thermal imaging report?

Accepted Answer

The report includes annotated thermal images alongside corresponding visible-light photographs for each area of concern, a description of the findings, and where appropriate, recommendations for remedial action. Reports are provided in PDF format and are suitable for sharing with contractors, insurers, or building control officers.

Question 12

What does a window, door and glazing inspection cover?

Accepted Answer

The inspection assesses the condition and performance of all installed windows, doors and glazing units. This includes checking for failed sealed units, inadequate or deteriorated frame seals, poor installation detailing, and any evidence of condensation or moisture ingress. Where conditions allow, thermal imaging is used alongside the visual inspection to identify heat loss and air leakage around frames and glazing that would not be visible to the naked eye.

Question 13

When would I need this type of inspection?

Accepted Answer

This inspection is useful in a number of situations — for homeowners who suspect their windows or doors are draughty or poorly performing, for buyers wanting to assess the condition of glazing before purchasing a property, and for builders or developers wanting to verify installation quality on a new build. It can also be a helpful first step before deciding whether to repair or replace existing units.

Question 14

What is included in a new-build completion package?

Accepted Answer

A new-build completion package combines the key assessments typically required at the end of a new-build project into a single, coordinated visit where possible. This includes the Part F1 air tightness test, the domestic EPC, and the collection of evidence for as-built SAP calculations. Gathering the SAP evidence, air test, and EPC together in one visit reduces the number of site attendances needed and simplifies the handover process for builders and developers.

Question 15

How does the package fit with Building Control sign-off?

Accepted Answer

The air tightness test result, as-built SAP evidence, and EPC are all documents that Building Control will typically require before issuing a completion certificate for a new dwelling. The test report and certificate are provided promptly after the visit so they can be submitted without delay. If you are working to a tight programme, get in touch early so testing can be scheduled at the right stage of the build.

Question 16

How do I get a price?

Accepted Answer

The best way to get a price is to get in touch via the contact page or by phone. Costs vary depending on the service required, the size and type of property, and the location. I aim to respond to all enquiries promptly and will provide a clear, fixed quote before any work is booked.

Question 17

What affects the cost of a service?

Accepted Answer

For air tightness testing and EPCs, the main factors are the floor area and the number of storeys. For thermal imaging and draught detection, the scope of the survey and the size of the property are the key variables. Travel time and distance from County Down may also be a factor for more remote locations. There are no hidden charges — the price quoted is the price you pay.

Question 18

Where in Northern Ireland do you work?

Accepted Answer

I cover the whole of Northern Ireland and am based in County Down.

Question 19

What happens after I get in touch?

Accepted Answer

Once you make an enquiry, I will get back to you to discuss your requirements, confirm the scope of work, and provide a fixed quote. If you are happy to proceed, we agree a date and time that suits you. I will confirm the appointment and let you know what, if anything, needs to be prepared on site before the visit. After the work is completed, the report or certificate is issued promptly — usually within one to two working days.

Air Tightness Testing

Domestic EPCs

Draught Detection

Thermal Imaging

Window, Door & Glazing Inspections

New-Build Completion Packages

Pricing & Quotes

Coverage & Booking

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