Tag Archives: U Value
There is mounting evidence to suggest that buildings that are being designed to achieve thermal performance standards, including standards set out within the current UK Building Regulations, are in some cases consuming in excess of 70-100% more energy than the predicted values. Plus, some would say more worryingly, that the Building Regulations do not set an adequate base level of performance and facilitate the delivery of many buildings of poor quality into the UK housing market
The age of your house is a fairly reliable indicator of its likely thermal efficiency especially if no upgrades have been made to the fabric of the building – although many houses have been extended or otherwise significantly modified over the years. Over the last 50 years, the level of insulation required in Building Regulations has changed drastically to reflect both the need to reduce heating bills and increasing demand for comfort from homeowners. Here we consider how insulation levels have changed and what difference it has made to energy use.
One of the most commonly used, and widely recognised, acronyms in construction is VCL, which stands for vapour control layer. A VCL is a critical building component designed to protect the building from potential degradation (or poor performance) by managing the passage of water vapour within a building structure. In other words, it is used to manage condensation risk. Condensation is formed when warm moist air condenses into a liquid on contact with a colder surface. A vapour control layer is typically installed on the internal side of the insulation to control the passage of warm moist air (water vapour) entering the structure. However, as a simple acronym, there is a problem because in most applications a specific level or type of performance is required, as a ‘catch all’ acronym VCL is wide open to error.
In the course of our day to day business, we encounter plenty of customers, builders and trades who find U values a little confusing especially when it comes to understanding what the U value actually means and how it will affect or benefit the performance of a building, so we have compiled a brief 'U-Value for dummies' style explanation to help.