Without doubt, there are issues that may need to be taken into account with our current status of installing Condensing boilers as a standard minimum requirement. The Government fully recognise that there are occasions when it is not feasible to install a Condensing boiler and for this reason, have allowed exemptions in the form of a points table guide, listed below, as well as cost consideration.

  1. Domestic Building Services Guide.
  2. Guide to the Condensing Boiler Assessment Procedure for Dwellings.
  3. Contact your local planning inspector – they are usually extremely helpful.
  4. Of course, you can always contact us.

Fitting a non-condensing boiler

If the following criteria are met, it is legal and acceptable to install a non condensing oil boiler as a replacement in an existing domestic dwelling.

Following an inspection and a completed CD30 form having been issued to the householder, if applicable, a non condensing boiler can be installed. The forms are available from the Planning Portal website.

The form calculates the qualifying points for the installation. The total points scored will determine whether it is acceptable to install a non condensing boiler.

If the points scored are over 1000 then it is acceptable to fit a non condensing boiler.

Points are scored for the following criteria –

Criteria Points
Building Type Flat

Mid Terrace

End Terrace, Semi-Detached, Detached




If the new boiler position is different from the existing boiler 350
If a condensing boiler is fitted will it be necessary to fit a flue more than 2 meters long from the boiler flue outlet to avoid: _
a) The flue discharging horizontally less than 2.5M from any wall, fence, building or the property boundary. 350
b) If the flue outlet is less than 2.1M above the ground, discharging less than 2.5M from a car parking space. 350
c) If the flue outlet is less than 2.1M above the ground discharging across a public pathway, a route or patio area. 350
If it is necessary to install a condensate pump or a soak away. 100

As well as these exemptions listed above, the overall COST, is also an important factor. If the installation of a Condensing boiler leads to having to overcome other consequential work which needs to be undertaken and the cost of this work is considered to be too high, then a Non Condensing boiler can be fitted.

Extra costs can arise from the following ;

  • Gravity fed and single pipe systems
  • Location of existing boiler – if it is centrally located in the property.
  • New flue, backfilling the chimney, scaffolding, location of condensate drain?
  • Re – siting a boiler.
  • Nuisance pluming issues.
  • Listed buildings considerations.
  • Soakaways having to be constructed.
  • Potential damage to septic tanks from condensate.

If you are in any doubt, contact your building inspector, or give us a call. The important factor is to match your new boiler to the property, the current system in place and that this should be at a reasonable cost. If a condensing boiler fits that bill, then that is what has to be fitted.

In some circumstances, it may actually be illegal to fit a condensing boiler if installation distances cannot be met.