Domestic Landlord Guide – Chapter 3

Chapter 3: Technical Advice for Landlords on making Energy Efficiency Improvements

Energy efficiency improvements should always be considered with an understanding of how the building was designed to perform, as well as how the building is likely to be used by occupants. Many of the principles of building performance and building use are generally applicable to all homes; however, some of these will be particularly relevant to private rented properties. This chapter highlights several technical issues that landlords may wish to raise when seeking expert advice on how to improve their properties.

As discussed in the previous chapter, when identifying appropriate energy efficiency improvement measures for a property, the first port of call for a landlord should be the recommendations page of the current EPC certificate for that property.

Many buildings hold historic value and special care must be taken in retrofitting them to a 21st century standard of performance while respecting these heritage issues. In order to make an informed decision about building improvements that suitably balances performance and heritage it is important to first understand how the building was designed to operate. A significant portion of domestic private rented properties can be described as “traditional buildings”, meaning that they were built prior to the widespread use of modern building techniques. Traditional buildings were typically built before 1920 and likely have solid walls of brick or stone.

Modern buildings include barriers that make them impermeable to moisture. Excess moisture from laundry, showers, and other occupant activities is typically controlled through ventilation. In traditional buildings, moisture is in part controlled by allowing it to evaporate through the walls themselves. This is sometimes called a “breathing building”.

From Historic England: Energy Efficiency and Historic Buildings (digital image by Robyn Pender)

If a building was designed to breathe, then changing the external envelope by adding energy efficiency improvements such as wall insulation can inadvertently trap moisture in the building as well. Unless efforts are made to control the relative humidity there is a risk of moisture building up, which could cause mould, adverse health impacts, and potentially damage the building as well. In some cases, it is possible for moisture and mould to build up within a wall, which can go unnoticed for long periods of time.

Incidences of damp are far more common among the private rented sector (PRS) than in the general housing stock. In order to protect the health and safety of their tenants, as well as their buildings, landlords have a role in both choosing energy efficiency improvements that are suitable for their buildings, and communicating these improvements so that their buildings can be used by their tenants without adverse consequences.

(MHCLG English Housing Survey 2017 Figure 2.7)

Warm air can hold more dissolved moisture than colder air.  When warmer air absorbs moisture then cools down, excess moisture forms as condensation. There are a number of ways in which this can occur, including changes to the heating system throughout the day, inconsistent temperatures between different rooms in the home, or local cold spots such as corners or thermal bridges. The heating system and ventilation controls can help both maintain comfort and limit the risk of moisture build up.

Landlords should note that simple upgrades that can be easily controlled are more likely to be used effectively. Some systems use passive control features like humidistats to automatically turn on extract ventilation when the space becomes too humid. Smart heating controls can be used to simplify the user inputs needed to keep the space comfortable. Finally, the provision of information through manuals and log books can be an effective way of communicating with tenants about how to use energy efficiency features most effectively.

Care must also be taken when installing insulation (particularly internal insulation) in order to avoid creating thermal bridges, or cold bridges. Cold bridges occur when one element with insulation is adjacent to another element without insulation. It is common around window reveals, hard to reach corners, or near party walls. Cold bridging is particularly problematic in retrofit projects because it changes the way heat flows out of the building. For example, if one insulates an internal wall, but not the window reveal, it creates local cold spots in an otherwise warm space. Condensation, mould growth, and potential structural damage can in fact be more likely to occur on the window reveal after the room was insulated than before. It is essential that any insulation project is undertaken with sufficient detailing to limit cold bridging.

There will almost always be multiple paths available that bring an F or G rated property up to an E rating. In many cases a single measure such as insulating solid walls or updating a heating system will be sufficient to achieve an E rating or better. However, it is recommended to seek professional advice on effectively combining measures using a “whole house” approach to ensure that the renovation upgrades are not only as efficient as possible, but also avoid the adverse consequences described above. In particular, note that even small energy efficiency improvements made separately over a long time period can have a cumulative effect that greatly changes how the building performs.

In many cases, improvements to the building also require changes in occupant behavior. In complying with the minimum standard requirements, landlords should consider the holistic performance of the building and aim to select a combination of measures that offer a suitable balance for the building and its occupants. The landlord should exercise caution and seek expert advice both in selecting the measures that will be taken and in communicating to their tenants how to effectively use those measures.

Landlords should also take care in selecting suitably qualified contractors with the range of expertise needed to offer advice for a specific building. This can be challenging, because as discussed above, a “whole house” approach to energy efficiency frequently reaches across the core expertise of many specialist contractors. Landlords should ensure that the advice they receive covers the performance of the whole house including interactions between different retrofit measures such as how adding insulation will affect the air tightness and breathability of the building.

Most housing retrofit work should be undertaken by contractors holding an NVQ – Level 3 qualification in a topic suitable to the work being carried out. It is also desirable if the contractor holds qualifications through a scheme such as PAS 2030. In nearly all cases, retrofit work will need to comply with the Building Regulations through either the Local Authority, an Approved Inspector, or the Competent Persons scheme. If the property in question is a traditional building, then knowledge of BS 7913: Guide to the Conservation of Historic Buildings is encouraged.

Landlords should attempt to become as informed as possible about both their homes and energy efficiency prior to approaching contractors for quotations on retrofit work. Further information is available through BEIS and other resources such as the Simple Energy Advice Service45. In addition to general advice on energy efficiency, there are a number of services available specifically for traditional buildings through groups such as Historic England

( Finally, there are often local services offered at the council level, and landlords are encouraged to approach their Local Authorities for more direct advice.


Property Type

Select button for EPC Type and Postcode, then hit the "Find Assessors" button. The search the page will then display assessors in your area

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Guidance for landlords and Local Authorities on the minimum level of energy efficiency required to let domestic property under the Energy Efficiency (Private Rented Property) (England and Wales) Regulations 2015, as amended.

This section is a distillation of the published Government regulations and was correct at the time of incorporating within the GO LOCAL EPC site. For a copy of the full original document please select this link THE DOMESTIC PRIVATE RENTED PROPERTY MINIMUM STANDARD.  This publication is licensed under the terms of the Open Government Licence v3.0 except where otherwise stated.


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Property Type

Select button for EPC Type and Postcode, then hit the "Find Assessors" button. The search the page will then display assessors in your area