There are approximately 25 million houses, and 2 million non-domestic buildings, in the UK and we build at a rate of 100,000 to 200,000 homes per year whilst demolishing a tiny percentage, so our stock levels are increasing, but the vast majority of buildings are old and consuming energy at higher rates each year due to our increased use of electronics, such as flat screen televisions, music players, computers etc and increased comfort levels required by occupants leading to heating systems being turned up a degree or two.
The reduction in our current use of energy by lifestyle changes would have a huge impact without the need for major expenditure. House refurbishment of existing buildings is obviously the other most significant area where carbon reductions can be made as the bulk of our buildings are very energy inefficient.
The last Government had a target for the house refurbishment of 7 million privately owned homes in order to reduce carbon emissions by 80%, but there are no major initiatives to entice home owners except the new feed in tariffs, aimed at offering annual cash rebates for installing photovoltaics (PV). This obviously solves one problem in terms of reduced carbon for each individual property that installs the equipment but makes much less difference to the global carbon demand as PV panels require a high level of energy to manufacture. A much more significant reduction could be achieved by installing natural insulation which are mostly carbon negative and have the ability to be reprocessed at the end of their life or burnt to generate more energy, resulting in a more eco friendly alternative.
The best approach to house refurbishment must take into consideration not just energy saving but on a broader level; resource efficiency, pollution, health and durability.
- Resource efficiency, selecting materials which are plentiful or replenishable
- Pollution, selecting products which are created and delivered to site without causing excess pollution at any stage in their processing.
- Health, considering the impact on all people in the chain including from extraction of raw materials to the occupants of the building and those who process the materials at the end of its life.
- Durability, products which have a life of greater than 100 years will generally have a reduced environmental impact compared with non-repairable short life products.
When selecting materials for house refurbishment we need to understand how the existing structure works in order to select the most appropriate products.
Older buildings have generally been constructed using porous, breathable materials, that allow a building to regulate the moisture. Most buildings built before the 1930s were built with lime and benefit from breathing wall solutions, such as natural insulation and lime renders.
Technically the best way to upgrade the thermal performance of a wall is to insulate externally thereby allowing the brick wall to become a thermal store. However there are aesthetic issues imposed by planning laws and our general desire to maintain the styles of our traditional buildings, so it’s not always possible to insulate externally. If insulation is applied internally to walls then care should be taken in the design to minimise the risk of interstitial condensation forming inside the wall as the brickwork becomes colder and can hold greater levels of moisture, which may result in long term issues. So the use of external natural insulation with breathable coverings such as lime render or cladding will be the most efficient and durable solution.
Upgrading the insulation horizontally in loft spaces is relatively straight forward and should be built up to a depth in excess of 300mm (12 inches) and the insertion of a raised deck desirable to maintain the use of the loft without damaging the insulation.
For rooms in roofs the use of externally applied wood fibre boards and soft natural fibre batts inserted between the rafters will result in the best overall performance as the materials breathe and help regulate temperature and humidity.
Upgrading insulation in suspended timber floors could save 10% of the energy used to heat the building, so is worthwhile but care should be taken not to reduce the air flow below the floor. Installing a membrane of wood fibre below the insulation will reduce heat loss caused by drafts across the surface.
Old single glazed windows & doors can have a significant impact on heat loss so replacing them with triple glazed windows and thermally insulated doors is desirable as it is possible to reduce U values to below 1.0 W/km2.
M & E Services
Fix the fabric, then consider the energy demand of the property once the need has been reduced. This reduces the size of any system installed and generally the upfront costs.
The hot water and heating demand for a typical older property accounts for over 60% of the carbon emissions generated by the ‘delivered energy’ to the property, so the combined emissions relating to lighting, appliances and cooking accounts for 40%.
Older boilers run at 50-60% efficiency, modern non condensing boilers run at between 60-80% efficiency, compared with over 90% for new condensing boilers installed into systems with the correct return flow temperatures. So combining a boiler replacement with thermostatic radiator valves and well placed thermostats will decrease your energy consumption dramatically.
Upgrading a heating system and installing solar water heating will reduce emissions by over 60% and energy use for a typical domestic dwelling.
In summary upgrading loft and floor insulation , upgrading windows and fitting solar thermal panels will be most cost effective and result in the most eco friendly, biggest carbon reductions.
Ecomerchant is dedicated to making ethically sourced, sustainable building materials accessible at affordable prices.
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Your Refurbishment Projects
Ecomerchant supply an extensive range of eco friendly building materials, we are able to assist with products and services for refurbishment projects ranging from; domestic premises to schools and commercial buildings. Contact us with details of your project and we will be happy to offer our assistance.