We have covered the basics in collecting data and surveying a residential property for an EPC. In this blog we are going to look at the basics for a commercial property, which is a little different. Whilst even a commercial property is going to have heating, lighting and a building fabric, the way in which they are used is very different; so the survey and the process of producing the certificate is different, to ensure it is a fair reflection of the property.

Preparing to visit

With commercial EPCs, especially on larger properties, it is really important to do your groundwork before you arrive on site. The customer can be really helpful here by providing floor plans and any history of the building, its uses and any other information on the building itself. Floor plans are particularly useful, as it is sometimes very difficult or just time-consuming to do a floor plan from scratch on site. In many cases, a lack of floor plan will add to the cost of the job.

Identifying zones

One of the key differences between commercial and domestic EPCs is that the commercial EPC actually considers the way in which the property is being used. Areas of the building are divided up depending on how they are being used, so that an office area would be divided from a toilet block, and a warehouse or storage area from a circulation area like a stairwell. In smaller properties, there may only be a couple of these zones; for instance, a shop with a toilet and storage area at the back would be 3 zones. Larger properties like hotels or office blocks could have dozens or even hundreds of zones, and each one of these zones will need each wall defined by its type and length.

This process is half the battle for the commercial EPC, so the assessor will spend much of their time dividing up the zones of the property on their floorplan or sketched map.

Checking HVAC

Whilst many homes do not have air conditioning, many commercial spaces use a heat pump for heating and cooling. Furthermore, there are a huge range of heating and cooling systems available for commercial spaces, so a very important step will be to identify the model of the HVAC system, identify the storage capacity of the hot water system, and identify the zones which the system supplies.


There are a much bigger range of lighting options for a commercial space, as well as a whole host of different controls and energy saving tech. As such, lighting can play a much bigger role in a commercial EPC than a residential, in some cases altering the rating by 2 or 3 whole bands.

The assessor will look at the fittings and add these to their notes. Where the type of bulb is not obvious, it is useful to provide a spare bulb with the packaging to let the assessor enter the exact details.


The surveyor will need to see your gas and electric meters. If you sub-meter your heating or lighting, then they will need to see these as well.


Unlike a domestic EPC, where the type of window is entered, along with information on whether or not there is a typical amount of glazing,  in a commercial EPC the amount of glazing needs to be entered for each elevation in a zone. The assessor will note the walls which have windows and how much area these windows cover. Doors are also considered with exact dimensions, allowing for larger vehicle access doors for example.


The level of insulation for the walls, floor and roof are all ascertained in the same way as a domestic EPC. If specific data such as a U and K-value are available, this can also be utilised, but in most cases the assessor will just take a measurement of wall thickness and note the type of construction. Just as with a domestic EPC, the assessor can only go on what they see on the visit, or on documentary evidence. If you have insulation present and it is hidden behind plasterboard or in a sealed roof space, do not expect to see this reflected in the EPC unless you have provided documentation to prove that it is there.


The orientation of the building is really important. This simply involves a quick check on Google Maps to work out where North is and to mark this on the site notes.


Unlike in a domestic property, where the amount of renewable energy present is quite limited by the size of the home, it is quite possible to have a huge amount of renewable energy in a commercial property. This is great for the EPC rating, but do remember to have the certification or notes from the installer handy for the assessor to take. This will allow a true reflection of the system in the final EPC.

Other considerations for a commercial EPC

We have just covered the basics here, but because commercial properties vary much more widely than a domestic property, there are many other things the assessor may need to consider on the day. We can however, tell you what they won’t need to see:

  • We don’t need to see your water meter.
  • The certificate does not take into account the quality of the construction, just the materials used in it. Nor does it consider the electrics or the plumbing in the building. It does not look at asbestos in the building. As a general rule, the EPC does not consider how well things are working. It will only consider whether you have them or not, and how efficiently they have been designed. For example, if your air conditioning is leaking and more inefficient as a result, the assessment will take the manufacturers efficiency levels and put these into the software, not work out an efficiency based on how well the system is operating currently.
  • The EPC does not take into account the efficiency of any processes within the building. You may have a production line with a super-efficient system for producing your products, but it is the building itself which is being considered as part of the survey, not the equipment used to produce your goods.
  • For offices, the computer equipment and other electronic goods are not considered. If you run a laundry, the washing machines are not considered; if you have an office, the computers are not considered.
  • Transportation is not part of the survey either, so we won’t be checking how many miles to the gallon your truck or your tractor gets. Nor will you get any points for having a biodiesel fleet or electric cars. The building is the only aspect to be considered for the EPC.
  • If your company has several buildings on the same site, each one will need a certificate, and each one is assessed on its own merits.

So there you go – if you need a commercial EPC, just let us know and we will be happy to help arrange your EPC.