Category: Uncategorized

Retrofit: Whole Building or Step by Step

There are two principal approaches to retrofit, ‘one-off’ whole-building or ‘over time’ step by step.

Whole building sees the structure as a system of different elements/interfaces with users that interact with each other. The retrofit is not a replacement of individual processes that are independent of each other, and also separate from the users’ lifestyle and practices.

Step by step undertakes isolated measures. These may be driven by regulation or policy, grant-aid availability, life span replacement or a system failure. This is a piecemeal approach that does not consider the interaction between the systems.

In the ‘whole building’ approach, the risk of not achieving the ultimate performance outputs is relatively low and is easier to evaluate at design stage, during the works and afterwards. In a situation where retrofit projects are carried out over time, there are risks where different techniques and interventions are not undertaken ‘as a whole’. The isolated measures ‘lock-in’ constraints and compromise future interventions that are likely to be undertaken by different people (designers and installers) none of whom may have responsibility for overall outcome or operational problems. Thermal imaging and air permeability tests after the works are completed may show that the whole building has not reached the desired energy performance.

This outlines why a main contractor like Coombs is an essential part of your net zero strategy.

Building a New Supply Chain

Coombs had an excellent day at the Kent Construction Expo on 7th October, with a busy stand from start to finish! A big thank you to everyone who came along to say hello to Jackie at the ‘Meet The Buyer’ event. We are building our ‘customer-centric’ supply chain for one-stop retrofit. This is an ongoing process, but we are always open to conversations with like-minded firms who are reliable and innovative.

Building Passports – Good or Bad Idea?

Is a building passport something that sounds good? Getting retrofit right involves sophisticated and expensive strategies, in some cases requiring multiple improvements and interventions. The result is energy use and carbon emissions from buildings that are very substantially reduced, but even after the inherently complex and risky retrofit process, there are across the UK examples of buildings damaged rather than improved, with serious damp and mould, or minimal improvement in energy performance.

‘Building Passports’ are a relatively new idea already gaining support in some European countries. Do we at Coombs think building passports are a good idea for the UK? Yes!

What is the definition of a net zero energy building?

Well that depends! There are many definitions for a net zero building…..

The World Green Building Council definition of a net zero carbon building is:

‘’a building that is highly energy efficient and fully powered from on-site and/or off-site renewable energy sources’’

The European Council for an Energy Efficient Economy states that a Net Zero Site:

‘’produces at least as much energy as it uses in a year, when accounted for at the site’’ and ‘’a net-zero emissions building produces at least as much emissions-free renewable energy as it uses from emissions-producing energy sources’’.

The US Department of Energy Building Technologies defines a Net Zero building as:

‘’a residential or commercial building with greatly reduced energy needs through efficiency gains such that the balance of energy needs can be supplied with renewable technologies’’.

The International Energy Agency gives the following definition:

‘’Zero Net Energy Buildings are buildings that over a year are neutral, meaning that they deliver as much energy to the supply grids as they use from the grids’’.

So we can see, despite all of the interest and excitement about Net Zero Buildings, there is not yet a common definition of what it actually means – but they are close!

Good behaviour brings rewards

Heat consumption in buildings depends on the thermal characteristics of the building structure, and the efficiency of the heating system. Additionally, it is influenced by the behavioural aspects of building occupants. If the occupants are not motivated to conserve energy, the final savings might be far below the expected level.

For example, in apartment buildings with a central heat source (district heating connection or central heating plant), it is better to allocate the heat costs between the apartments. Past experiences have showed that a cost allocation based on the floor surface area of an apartment does not encourage the optimal energy use among the occupants. Thus, the individual heat metering in apartments is one of the energy efficiency measures that enables energy saving, by introducing the principle of accurate billing based on the actual consumption. This is technically feasible, and cost-efficient.