We have recently been helping some new self-build clients, who live on the border of Oxfordshire and Berkshire, to improve the energy efficiency of their new build home designs.
Having already achieved planning permission, their brief was for our eco-expert to look over their architect’s plans, before they were finalised. They asked us to comment on what could be done to further improve the energy efficiency of their new home before the building regulations details were approved. Our clients were aiming to achieve the best environmental performance, without incurring excessive costs.
Our clients were considering a number of renewable technologies, and wanted an independent expert’s view on which of the options would be most suitable for their new build. The technologies under consideration included ground source heat pumps, air source heat pumps, underfloor heating, photovoltaic arrays, solar hot water and wood burning stoves.
We always talk to our clients about approaching their energy efficiency designs from a ‘fabric first’ perspective, before then looking at energy saving technology.
We therefore approached this brief by looking at 3 main areas:
1. Sustainability matters
Here we look at design elements such as improving air tightness and reducing air leakage. We look at getting rid of thermal bridges and improving the U values of the windows, the walls, and the roof. We check the designs with regard to solar gain, ventilation, insulation and other construction details.
2. Heating and plumbing details
Here we assess the needs of the client, and the location and design of the building. We then report on the pros and cons of the various suitable systems that our clients could consider.
3. General practicality
Here we are looking at improvements to the designs that would reduce costs, improve the quality of the living space or make things easier to construct.
The output of this review involved giving our clients clear, practical notes and annotations on their architectural drawings. The costs of the various options, as well as the government grants and incentives available, enabled us to outline the various payback scenarios. The aim of this practical approach was to help our clients to make the necessary financial decisions and then help brief their architect for the preparation of the final building regulation drawings.
The second stage of our brief was to carry out a Standard Assessment Procedure (SAP) for the final building regulations drawings. A SAP is the methodology used by the Government to assess and compare the energy and environmental performance of dwellings.
Before carrying out a SAP, our sustainability expert ran our in-house thermal model to show were the SAP result would lie, and identify cost-effective approaches to meeting the SAP requirements. We inputted the dimensions from the drawings to the model, inputted the U values and air tightness, and produced results which indicate where heat is lost in the building (split by elements of structure and air tightness). We also calculated the overall peak heat requirement in coldest weather, indicated the annual heat requirement and any identified anomalies and perceived problem areas for over-heating or where we found it would be difficult to keep a part of the building warm.
We then provided the On-Design SAP result (passed) for this initial design, as the design was now the final regulations drawings. We structured our reports with short explanatory written notes including pie-charts. We also gave budget estimates which are based plus information on U values, or a build-up of structure including insulation materials from which U values can be estimated. Once built, a model of this sort can be adjusted quickly to run other scenarios so that clients can check the effect of the options before deciding and proceeding with their final drawings, from which we calculate their SAP.
Are you planning a self-build project?
If you’d like to find out more about what a self-build home energy efficiency review can do for you we’d love to chat. Call 01923 896550, email firstname.lastname@example.org or complete a contact form.
CLPM Services used by our client:-
Energy Efficiency and Heating Design Review.
If you are planning a self-build project it makes sense to build with future sustainability in mind.
Building regulations should be viewed not as a target but as the lowest legal standard. Getting an independent energy consultant like CLPM to review your plans is the first step to build a more sustainable home.