Custom energy label app development
An energy label app is the survey and workflow layer around the work of the EP adviser: it records the on-site building survey according to the survey protocol, with photos and evidence for each characteristic, and passes that data on to certified calculation software, which determines the label and registers it in EP-Online. Appfront builds that layer to measure for energy advisory firms, housing associations and property managers who want to speed up their surveys without compromising on file documentation.
What does an energy label app do?
An energy label app supports the building survey and the file surrounding it. It does not do the calculation itself: a valid energy label is determined using the NTA 8800 assessment method, and that calculation must be carried out in certified calculation software under BRL 9501, in line with RVO rules. The adviser who prepares and registers the label works under BRL 9500, with the competence that applies to the building: EP-W/B or EP-W/D for residential buildings, EP-U/B or EP-U/D for non-residential buildings.
That makes it clear straight away where custom software makes sense and where it doesn't. Building an app that calculates the label itself is not a viable route as long as it isn't certified. Where time does leak away is at the edges: the on-site survey, gathering evidence, retyping that survey into the calculation software, scheduling advisers across addresses, and the client asking where their file is. That is the layer we build.
In practice, we see advisers working on site with a paper survey form or a general note-taking app, then entering the data again afterwards. Every transfer is a chance for a typing error that only surfaces at quality control, by which time the adviser is three addresses further on. A survey app that follows the protocol's order of entry and asks for justification per characteristic removes that double entry and makes the file complete straight away.
If the label applies to non-residential buildings, a second obligation has also applied since the end of 2025: buildings above the capacity threshold must have their energy consumption continuously analysed. The control in the technical room that goes with this is covered by the installation control app.
Alongside the label, many buildings are subject to a periodic inspection requirement for heating and cooling systems. Which installations fall under this and when the next inspection is due is covered in EPBD software.
A lot of the figures that end up in the later documentation originate from a survey carried out in the property. How to record them at source is covered on the page about the app for on-site surveys.
How we build your energy label app
We start with the capture itself and only then with the systems around it. An app whose location input is wrong won't be used, however good the integrations are.
We walk through your survey process step by step: which building types you cover, what qualifications are required, which calculation software you use and how the file is currently put together. We also look at what goes wrong during quality control, as that is the quickest way to see which data is missing on site.
The survey is the heart of the app. We design the data entry in the order in which an assessor actually moves through a building, with the evidence required for each characteristic. We decide which fields are mandatory, which depend on earlier answers, and where the app should warn rather than block.
We work in sprints and deliver something at the end of each sprint that your assessors can genuinely use. Early in the project, an assessor takes an interim version into a real building; this teaches us more than any workshop, because you only find out in the loft which field is buried too deep in a menu.
We connect to your calculation software and, where it's useful, to EP-Online and your own planning or invoicing systems. This is followed by a handover to your team, with the documentation your quality manager needs to assess the app independently.
What an energy label app actually does
Six components that come up in almost every project. Which ones you need depends on whether you carry out surveys for third parties or for your own portfolio.
Survey that follows the protocol
Data entry follows the order in which the assessor moves through the building: dimensions and orientation, construction year and structures, insulation and glazing, ventilation and installations. Fields that don't apply disappear based on earlier answers, so you're not left with a list where half the fields are empty.
Evidence per characteristic, not per survey
A photo is attached to the characteristic it supports rather than to the file as a whole. During quality control it is immediately clear where the entered insulation thickness comes from, rather than someone scrolling through eighty loose photos.
Works in crawl spaces without signal
Cellars, crawl spaces and concrete stairwells have no coverage. The app stores data locally and synchronises as soon as connectivity returns, with a clear notice showing which surveys have not yet been sent. See also our guide to offline working and synchronisation.
Passing data to your calculation software
The survey goes to the certified calculation software you use as a structured data set, rather than someone retyping it. Which route that will be depends on what your supplier offers; we establish this during the discovery phase before promising anything.
Scheduling and addresses
Addresses are assigned to assessors, taking qualifications and building type into account, and the day's route is put in order. In the app, the assessor sees what is scheduled that day and whether anything is still outstanding at an address from an earlier attempt.
Client portal
Housing associations and property managers want to see for themselves where their order stands. A portal showing the status per address, the issued label and the underlying file saves you the email back-and-forth that would otherwise arise.
Who we build for
Four types of organisation with different starting points. The difference lies mainly in whether the survey is your product or a means to an end.
Energy advisory firms
You carry out surveys for third parties, and your margin lies in the turnaround time per address. The gain comes from eliminating duplicate data entry and from quality checks that intervene at the source rather than after the fact.
Housing associations
You manage a portfolio whose labels expire at different times and in which sustainability improvements are ongoing. A dedicated survey and records layer alongside your housing association software keeps track of what has been measured where.
Property management and estate agents
For sales and rental, a valid label is mandatory, and a missing one halts the transaction. Integration with your property management software makes visible which property is due when.
Installers and sustainability specialists
You carry out measures and want to substantiate their effect for the resident or owner. In that case, what you want to record is the survey before and after the measure, with the same characteristics and the same evidence.
Test your idea first: a working prototype in 1 day
With OneDayBuild, we turn your idea into something tangible in one day for €1,150, so you can see whether further development is worth the investment. Decide to go ahead with the full build? Then we credit the full cost.
Explore OneDayBuild →Technology and integrations
What we deploy depends on your situation. For capture work, offline operation weighs most heavily; that determines the choice of storage and synchronisation more than the choice of app platform. We only build integrations once we have established which interface your calculation software actually offers.
For new builds, with calculations according to NTA 8800 and a version for each design change, there is our software for the BENG calculation file.
If you want to manage the labels of an entire portfolio, including validity dates and obligations, there is our software for energy label management across a property portfolio.
Why Appfront
Quality control at the source
We build the checks in at the moment of data entry, not as reporting afterwards. A missing justification that is spotted on site costs a minute; the same finding two weeks later costs a second visit.
We immerse ourselves in the trade
Before we design anything, we accompany a survey. The difference between an app that works on paper and one that works on a sloping roof in the rain lies in details that nobody mentions in a meeting room.
Honest about what custom development cannot solve
Determining the label belongs in certified software under BRL 9501, and we will not rebuild that. We say so at the outset, so that you do not discover halfway through that part of your wish list is not feasible.
Connecting to what is already running
Your calculation software, your planning and your invoicing remain in place. We build the layer in between, because an app that becomes its own island produces exactly the duplicate data entry you wanted to eliminate.
Security and privacy
A building survey contains data about a dwelling and often about the resident: address, photos of the interior, sometimes a name or an appointment time. This is personal data, and it requires a legal basis and a retention period. We set up the app so that no more is recorded than is necessary for the survey, that photos of residents or their belongings do not end up in the file unnoticed, and that a file is genuinely deleted after the agreed period.
On the device itself, encrypted storage is the starting point, with a lock that is independent of the phone. An adviser who leaves their device in an empty property must not expose a portfolio. Roles and permissions follow professional competence: whoever is qualified for EP-W/B does not see non-residential surveys. Every change to a survey is logged, because in the event of a complaint or a spot check it must be possible to reconstruct who changed what and when. How we handle security ourselves is set out in our information security policy, and reports from outside go through our vulnerability disclosure policy.
Frequently asked questions about an energy label app
An energy label app is the capture and workflow layer around the work of the EP assessor. It records the on-site building survey in line with the survey protocol, with photos and supporting evidence for each characteristic, and passes that data to the calculation software that determines the label. It also manages address scheduling, quality control and the file handed over to the client. The calculation itself is not part of it; that belongs in certified software.
No, and that is a firm boundary. A valid energy label is determined under NTA 8800, and the calculation must be carried out in calculation software certified for that purpose under BRL 9501. Software you commission yourself does not hold that certificate. What we can do is structure the survey so that it feeds into that certified software without manual re-entry. That is where most of the time saving in practice is found.
BRL 9500 concerns the assessor and their work process: the requirements under which an EP assessor is certified and the regulations according to which they carry out the survey and the label determination. BRL 9501 concerns the calculation software itself and its certification. For your app, this means it supports the assessor's work but replaces neither the assessor nor the software.
EP-Online is the national database run by RVO that holds all registered energy labels. The qualified assessor registers the label there once the assessment is complete. To retrieve registered labels, there is a web service for which you request an API key from RVO. Whether connecting is worthwhile depends on what you need: for a portfolio, retrieving existing labels is often more useful than the deregistration side, which sits in your calculation software.
Yes, and for this kind of work that is not an extra but a requirement. Crawl spaces, cellars and concrete stairwells have no signal. We build offline-first: the survey is stored locally on the device and syncs as soon as there is a connection, with a clear view of which surveys are still outstanding. The tricky part is not saving the data but merging it when two people have worked on the same address; we design that handling explicitly.
That depends entirely on scope: how many building types you cover, whether integrations are added, and whether planning and a client portal need to be included alongside the survey. We only give a substantiated answer after the discovery phase, because a figure without that discovery is little more than a guess. In the first conversation we will say which components take the most time and which you could postpone.
Quite the opposite. The app does not replace your calculation software, it feeds it. In the discovery phase we look at what your vendor offers in terms of import or interface; that determines whether the handover can be fully automatic or whether an intermediate step remains. We only promise that integration once we have established what is technically available.
An inspection app is broader and not tied to a single protocol: you design the checklists yourself. An energy label app is focused on the building survey for energy performance, with the characteristics and evidence that go with it, and with the EP-W and EP-U competences as the basis for roles. If you carry out other inspections alongside energy labels, we often build one app containing both workflows.
Ready to build an energy label app?
Tell us how your survey process currently works and where time is being lost, and we will help you think through the order of the survey, the integration with your calculation software and what you could postpone. We build this as a standalone app and as part of a broader custom software or app development project.