Zero Carbon Buildings
The Committee on Climate Change have just published their much anticipated ‘Net Zero’ report (2nd May 2019), which provides a route map for how the UK can lead the way on tackling climate change, and how we can have Net-Zero Greenhouse Gases by 2050.
The report highlights a number of areas where the efforts need to be focused. One of these is the construction industry.
The technology already exists for the construction industry meeting this tough, but achievable, challenge. As Architects, we have already used a number of the techniques and systems which the report recommends using.
Here are some tips on what we’ve learnt from our own research and development work over the last few years:
Insulate, insulate, insulate!
The first step is to insulate the building, so it retains the heat during the winter, and keeps cool during the summer. It’s the most cost-effective way to reduce the amount of energy you use in order to keep your building at a comfortable temperature.
Insulation regulations have changed a lot over the past 10 years with big increases in energy efficiency in 2010 and 2013. For instance, in the late 1990s wall insulation thickness in a new home was typically 25mm thick, compared to 100 – 150 thick under the current regulations (using PIR Insulation). There’s always room for improvement though and the insulation requirements in the Building Regulations will need to be upgraded further if we are going to meet the 2050 climate change targets. Another 50mm of insulation can potentially bring the U-Value down from the current minimum level of 0.18 W/m2K etc to 0.14 W/m2K.
At the moment, increasing insulation in houses is a voluntary choice. As a practice, we do talk to our clients at the start of the design process to try and persuade them to allow us to exceed the current regulations and create a building which uses less carbon. Not only is this an ethical decision, it is also one which will make the building cheaper to run.
Finally, there is the choice of insulation. An ethical choice is to use a natural insulation such as sheep’s wool. This product is becoming more widely used and comes from a sustainable source.
Moving towards greener heating systems
The Climate Change report mentioned the need to move away from fossil fuel powered boilers, towards low carbon heating systems such as heat pumps. Heat pumps are electrically powered systems, which are best described as a refrigerator acting in reverse. The efficiency of these systems has improved markedly over the past few years, and its now possible to retro-fit an Air Source Heat Pump into an existing house with conventional convector radiators. It looks as though these units will become more main-stream over the next few years, and that they’ll continue to improve.
We’ve used Heat Pumps on a number of projects whether it be Air-Source, Water-Source or Ground-Source. The feedback we’ve had from clients has always been positive, and they do seem very cost effective to run compared to oil or gas; especially if they are used in a building which is fitted with Photo-Voltaic Panels.
Solar Thermal Panels are a proven way of heating hot water during the summer months. During other times of the year, the panels can partially heat the hot water tank, leaving less work (and energy) for the main heating system to bring water to the desired temperature.
Of course, you can make your existing heating system a lot more efficient by insulating your house to reduce the amount of energy you need to heat the property in the first place!
Using highly efficient appliances and lighting systems
The efficiency of household appliances and lighting has improved greatly over the last 20 years, so much so, that the technology now exists to run a household using surprisingly small amounts of power.
We’re working on an exciting project at the moment with a client who wants to power a house using ordinary network cable. The house is lit by LED lights and uses 12v DC current to power all the household appliances.
The electricity is provided by Photo-Voltaic Solar Panels, with excess power being stored in a battery; meaning that the property is effectively off-grid.
This technology is improving all the time, and we expect to see massive advances in this area over the next few years. Continuing improvements in the efficiency of household devices will also help to lower the electricity consumption for dwellings, which should make a huge difference to each home’s carbon footprint.
The need to retro-fit older buildings
A Government Survey in 2015 found that over 75% of UK houses were built before 1980, and 24% were built before 1919. Seeing as insulation standards have only increased dramatically in the past 20 years, these figures demonstrate that there are a lot of houses out there which don’t meet the current standards. If the UK wants to meet its commitment of being a nearly zero carbon society by 2050, then these older buildings are going to need some attention too.
We have had experience of retrofitting older houses, by adding insulation and energy efficient heating systems; but by still retaining the character of the original building. Recently we helped to bring a Victorian House up from a ‘F’ rated EPC to a ‘B’ rating, which is a huge step. The owner of the property has already fed back to us that their heating bills have reduced dramatically! (See photo attached)
These measures can also apply to Historic Buildings. We’ve recently worked on a Grade II Listed Church where Photo Voltaic Panels and a highly efficient Air Source Pump Heating System have been discreetly fitted to power and heat the building. The church has reported that they now generate virtually as much energy as they use. The Air Source Heat Pump is not only significantly cheaper to run than their previous heating system, but it can also keep the building at an ambient temperature during the winter outside service times, which is great for preserving and maintaining the building’s fabric.
We therefore welcome the report and its findings, along with the tough challenges it sets. At HPA, we regularly use the techniques and technology which can help move our Country towards the virtually zero carbon goal. But at the moment, only some of our clients choose to voluntarily surpass the levels for energy efficiency set within the Building Regulations.
The last time there was a major improvement within Thermal Requirements within the Building Regulations, the Standards were quickly accepted by society as the ‘norm’. Therefore, the Building Regulations need to change again, if the government want to make building virtually zero carbon an accepted mainstream occurrence.
Therefore, if you are designing or upgrading a building and you want to make an immediate difference straightaway; make sure you over insulate!
Written by Richard Wooldridge BArch (Hons) Dipl Arch RIAS RIBA AssocRTPI
Director – HPA