The information in the Energy section sets out ways to help you reduce the energy you use in your home via insulation and energy efficiency and also ensure that it comes from renewable sources, thereby reducing our dependence on fossil fuels.

MCA provides helpful information and useful external resources along with articles about sustainable energy projects in the Staffordshire Moorlands 

The aim of the MCA Energy page is to provide:

  • Helpful information
  • Links to useful resources
  • Local examples of sustainable energy projects

In the UK, a long tradition of house-building has resulted in draughty, poorly insulated, inefficiently heated (primarily with fossil fuels), housing stock unsuited to our cool, wet and windy climate. Similarly, this has continued into current building design and construction, except for notable exceptions in one-off individual designs. In the light of the current climate emergency, there is little evidence that planning decisions, building regulations or commercial pressures will promote the radical changes needed to make our homes sustainable.

Obstacles to progress in the UK include:

  • Lack of unbiased information
  • Concern about costs
  • The innate conservatism of planners, designers, building professionals and heating engineers

On the other hand, some European and Scandinavian countries, (along with parts of North America), have forged ahead with high insulation standards and renewable energy sources (for example, heat pumps and solar PV), for individual homes and community buildings. Some have attained the gold standard known as the ‘Passive House’ .

Resources: Ofgem and the Energy Saving Trust are good sources of information. External links to commercial suppliers and products in the following text are based on the personal experiences of MCA members. Our advice is to always research a range of products and suppliers before beginning a new project.

 

A. Measures to reduce heat loss (Insulation)

Most of our houses are poorly insulated by international standards and simple, cheap measures can make a considerable difference. A simple survey can reveal issues, whilst a professional survey using infrared imaging to assess internal and external surface temperatures can give detailed information about heat loss.

 

1. Draught proofing

Cold draughts are easy to detect and easy to fix. Door and window seals are cheap and effective. Suspended wooden floors are usually ventilated with air bricks beneath and gaps between boards or around walls may admit cold draughts. The airflow to joists is needed to prevent rot but draughtproofing or insulating boards may be possible.

Remember that any fuel burning appliances in the house need an adequate air supply so think carefully before making a house airtight. Dedicated air inlets from outside are one solution for stoves etc. Some airflow is also needed to remove the atmospheric moisture from cooking, washing and even breathing, so airtight buildings need proper re-cycling, de-humidifier and heat recovery systems.

 

2. Roof insulation

Traditional roof insulation consisted of a relatively thin layer of mineral wool laid across the loft floor. This is totally inadequate and a cheap and simple solution is to add a thick layer of mineral wool insulation on top of the existing layer. An alternative or additional measure is to install rigid insulation boards beneath roof tiles, either from underneath or as part of a roof replacement. Kingspan and Celotex are major suppliers of insulation boards and the best for this purpose have aluminium foil bonded to each side. It is easily cut with a saw and can be fitted between rafters. A suitable combination is 10mm thickness between rafters and 5mm sheets nailed or screwed below rafters to hold it in place and cover gaps. With a semi-permeable tiling membrane or no tiling membrane above, the roof timbers are aired adequately to prevent rotting. The Energy Saving Trust has useful information on insulation and there is financial support available to some groups of homeowners.

There is some concern that production of insulation materials is a high carbon process and that they are environmentally unfriendly materials. This needs to be balanced against their effectiveness and durability.

 

3. Windows

Modern window systems are double glazed to comply with building regulations but a lot of older homes still have single glazed windows, sometimes huge areas in traditional sash windows, and these cause massive heat losses. Where window replacement is impractical, secondary glazing may be a suitable alternative. Ornamental windows and conservatory roofs may be single glazed or have poor performance standards. 

All double glazing units are not the same. Look for units with the largest possible gap between panes and filling with inert gas. Manufacturers should mark each unit with the U-value. Triple glazing is common in cold climates and worth considering if cost and design considerations allow.

Many window systems are fitted with trickle air vents and these can be a source of draughts and heat loss, so consider when they need to be open or closed.

 

4. Underfloor insulation

Many new houses have solid concrete floors on the ground floor and, to comply with building regulations, these should have adequate insulation below the screed. A suitable insulation layer is 10mm of Kingspan or similar placed either between the damp proof membrane and the concrete floor pad or between the concrete and a screed. Underfloor heating pipes, if used, would be clip fastened to the insulation and the screed laid over. 

If you own or are buying a modern house, do you know the specification of the floor insulation?

Many older houses have solid floors, consisting of ceramic tiles or stones laid in a mix of ash and lime, with no damp proofing. These floors are, not surprisingly, cold and damp and it may be possible to re-lay them with a DPM and insulating layer.

 

5. External wall insulation

The external walls of a house comprise a large area and potentially the second biggest source of heat loss after the roof. Building regulations specify the insulation requirements for external walls and, in traditionally built UK houses, these will typically consist of an external brick wall, a cavity filled with insulation sheets or mats and an interior wall of insulating blocks. Timber framed buildings are totally different structures and can perform better or worse, depending on design.

Our older housing stock is much more varied, from uninsulated cavity walls through solid brick and tile-clad walls to solid limestone or gritstone buildings with very thick walls. Secondary cavity wall insulation is commonly performed by injection techniques but has many pitfalls. 

The worst performing walls are solid limestone, with very poor insulation characteristics. The “obvious” solution is to dry-line the building by applying an insulating layer to the inside – typically plasterboard backed by 5-10mm of Kingspan – either fastened to battens or stuck to the walls with special adhesive. This provides effective insulation, though the obvious snag is reducing the internal room size. However, the biggest potential problem is sealing the wall against movement of moisture. This can result in water condensing within the wall and causing invisible damage to the structure – these buildings generally had lime mortar and lime plaster, all allowing water vapour to move freely across the structure. There is conflict here between building regulations and advice from conservation specialists. Some new materials and systems are appearing to deal with the problem of insulating traditional stone buildings using wood fibre (e.g. undefined) and may be worth considering.
One product recommended by a member as a simple solution is Wallrock Thermal Liner , an insulated wallpaper. However, the supplier cautions about fire resistance so it needs evaluation. The product is listed as breathable (depending on surface treatment too), so it should be suitable for traditional stone buildings.

 

6. Chimney insulation

Blocking chimneys to prevent heat loss & cut out draughts

 

B. Reducing energy consumption directly

Insulation of homes is a really efficient way of reducing energy needs and there are other ways to make significant reductions in energy consumption. Whilst compact fluorescent bulbs and tubes were “state of the art” in 2010, they were often disliked for slow switch-on and poor light quality. LED technology has been a dramatic advance in both light quality and energy conservation. Look at all the light fittings in your home or business and consider changing to LED wherever possible – typically this could halve the lighting energy input and improve the quality of light at quite low cost.

 

Reducing room thermostat settings and aiming for constant temperature throughout a house may improve comfort and energy efficiency. Even lowering the setting by 1DegC is useful. Wearing a jumper and not just a T-shirt in the house used to be the norm. A recent newspaper article listed the average UK room temperature in 1960s as 12DegC! 

 

Smart energy meters, with in-house displays can be useful tools in prompting us to think about unnecessary energy consumption – what is the effect of turning off unneeded lights or turning off electronic equipment instead of leaving on stand-by? When used with micro-generation systems, they can suggest when surplus energy makes it sensible to use washing machines, etc.

Heat pumps

There are two distinct types of heat pump, air source and ground source. Each uses stored solar energy plus electricity to produce about 3.5kW of heat energy for every 1kW of electricity input. 

 

Air source heat pumps

These can be sub-divided into air-to-air and wet or air-to-water systems. In both, the external component is a cabinet containing a large fan, heat exchanger and compressor. 

https://energysavingtrust.org.uk/renewable-energy/heat/air-source-heat-pumps

These can operate at air temperatures down to -20degC, though efficiency declines at lowest temperatures.  Air to air heat pumps need a complex indoor system to distribute warmed air via ducts, so they are better suited to commercial and community buildings than homes. 

 

Ground Source heat pumps

These are the most efficient heat pumps, drawing heat from the ground (i.e. stored solar energy) via ground collectors filled with circulating antifreeze solution. 

https://energysavingtrust.org.uk/renewable-energy/heat/ground-source-heat-pumps

The commonest ground collectors are long coils of pipe laid horizontally in trenches 1m deep and 1m wide, so they require considerable space. However, vertical collectors and bore hole collectors are alternatives. Clay soils make for good ground collectors, whilst thin sandy soils are poor. Rocky ground is really unsuitable. A typical heat pump is like a big fridge-freezer, possibly with a similar sized hot water storage tank, and requires quite a lot of external pipe work.

 

Radiators or underfloor heating?

Though heat pumps provide lots of domestic hot water at 40+degC, they produce much lower temperatures on the central heating side, typically 30degC. This means that much bigger areas of radiated heat are needed than for conventional boilers and wet underfloor heating is the best option. This works best in a solid, well insulated, floor but is also fine with engineered timber flooring, using aluminium spreader plates as channels for the plastic pipes

 

Heating engineers may recommend just using larger radiators but this may be unsuccessful. Low temperature means low kinetic energy, so the radiators don’t generate effective convection currents of warm air to distribute heat. An effective solution is to use high efficiency fan boosted radiators such as Jaga: https://www.jaga.co.uk/lst-heating-radiators/tempo

 

Buffer tanks

An underfloor heating system and low capacity radiators means that there is quite a low volume of water flowing around the system, compared with conventional large radiators. If individual room thermostats are added to the system, as is often the case, a heat pump or any other energy source can become inefficient, repeatedly cycling on and off in response to rapid changes in return flow temperature. A solution to this is to install a large “buffer tank” so that the output from the heat source is used to heat this large reservoir from which the circulating water is drawn. 

 

Solar

Heat pumps are indirect ways of using solar energy, via the air or ground, and an alternative is to use solar collectors, roof or ground mounted.

 

Solar water heating is relatively cheap to install and may be worth considering as a supplement to a conventional heating system, though it may require an additional hot water tank and is generally not compatible with combi boilers. It is unlikely to be compatible with or to add any benefit to heat pump systems.

 

Solar photo-voltaic (PV) systems to generate electricity are more popular (but see sections on grants and economics) and becoming more affordable. They consist of large panels mounted on frames, either on a roof or near the ground and, for residential properties, generally do not require planning permission. The output from panels can be connected to the mains, via an inverter and control equipment, or can be stored in battery arrays for off grid properties or to even out supply and demand. South facing locations are preferred and shading from trees or other buildings can dramatically reduce output, even if only a small part of the array is shaded. Current regulations permit a maximum of 3.6kW of micro-generated electricity to be connected to a single phase of the grid and installation must be certified by a registered professional installer.

 

An optional extra for solar PV systems is a diverter to use any surplus energy to heat domestic hot water instead of exporting it to the grid. An example of this system is the Solic 2000

 

Wind

Wind power is a good energy source in the right location and wind turbines range from small direct drive turbines, typically 5kW maximum output, to large geared turbines generating 15kW upwards. Installation costs are high and a proposed installation needs thorough assessment of ground conditions, average wind speed and any obstructions such as trees and buildings, as well as planning permission. A big advantage of a wind turbine over solar PV is that energy is generated 24 hours a day and, unlike sunshine, we get most wind during winter months, when the energy requirement of a house is greatest. As with solar PV, the ending of feet-in tariff makes the economics of a domestic turbine doubtful. Britwind is a UK manufacturer and installer of small turbines. 

 

Hydro

Water power from a constantly flowing stream is potentially a great energy source for electricity generation but is complex and expensive to engineer. It has potential for a community energy scheme.

 

Biomass

Biomass energy systems range from large scale industrial schemes (e.g. wood or straw burning in power stations; digesters producing methane gas) to domestic wood burning stoves and boilers. Although widely regarded as renewable energy systems, this is only the case if the fuel is replaced – pruning actively growing trees or re-planting to replace felled trees. Wood pellet domestic boilers may use wood from non-sustainable sources and involve high carbon transport of bulky loads, often imported. Suppliers of kiln dried logs may be using fossil fuels or electricity to hasten the drying process, whereas naturally seasoned wood has a much lower carbon footprint.

 

Eco Angus manufacture a range of wood gasification and wood pellet boilers and other downdraft batch boilers are available. The Eco Angus range is MCA certified and eligible for Renewable Heat Incentive payments, which would make them an attractive option in the right situation. As a back-up to a log burning boiler, an electric boiler is an option (e.g. Fischer and Daxom) though electric supply requirements are high, so the supply needs to be checked first. Also, the RHI conditions generally exclude optional alternative heating.

 

See the section above on buffer tanks – these may be appropriate for wood boilers as well as heat pumps.

 

Domestic wood burning stoves are very efficient room heaters but need a constant supply of dry logs (1-2 years of seasoning under cover) or they will be inefficient, polluting and cause dangerous tar deposits in chimneys. New UK regulations limit the emissions of wood stoves and some manufacturers (e.g. Esse) have produced helpful information on new developments. In choosing a wood burner, it is important not to select a much bigger stove than needed – a small stove running at a high temperature is much more efficient and less polluting than a big stove that never really gets hot. Some stoves have a water jacket so they can provide domestic hot water or supplement a central heating system. Whilst attractive in principle, this can result in heat being removed too rapidly from the stove, leading to a low working temperature and inefficient burning.

 

Esse and other manufacturers supply wood fired cooking stoves, styled like original Aga/Rayburn cookers, that may be single purpose or include a water jacket for heating/hot water. These can be very efficient but, if you are considering the central heating option without an alternative heat source, think hard about the amount of firewood you will need, the regular stoking and what happens if you go away in winter. Whichever type and make of wood fired cooker you consider, it is crucial that it is designed specifically for wood burning – expecting a conventional solid fuel cooker to burn wood efficiently and controllably, even if “converted” is unrealistic.

 

Wood pellet boilers are possibly a direct replacement for gas or oil fired domestic boilers and eligible for Renewable Heat Incentive. They require a regular supply of processed wood and bulk storage, with a mechanised feed system. Yougen is a website with useful information on this technology.

 

Grants

Renewable Heat Incentive (RHI)

The RHI scheme is still in operation and, paid quarterly over 7 years, it can cover a large proportion of the capital cost of a renewable energy scheme. There is lots of information online, together with an application pack. A key requirement is that the installation has a certificate of compliance from the installer https://www.altoenergy.co.uk/government/domestic-rhi

 

Feed-in Tariff (FIT)

FIT provided a big incentive for homeowners and businesses to install micro-generation schemes such as photo-voltaic panels and small wind turbines. However, after progressive reductions in tariff, the scheme has now closed, though Ofgem has details of an alternative scheme, the Smart Export Guarantee

 

Economics and sustainability

The new Smart Export Guarantee (SEG) appears to depend on negotiation between a potential generator and a licensed energy supplier and the payment to be only for energy actually exported to the grid – FIT paid for all energy generated, regardless of whether it was used on site or exported, plus an “export premium” for 50% of generated energy on the assumption that this would be the average amount exported. FIT payments could be expected to pay back the capital cost of the installation over 7-10 years, with a guaranteed index-linked payment for 20 years, whereas the economics of a new system will be very different. 

 

Despite the lack of financial gain, it can still be worth considering micro-generation because the cost of solar PV installations has fallen considerably and may continue to decline. In contrast, small wind turbines are still an expensive option. What makes all the difference to economic and environmental considerations is whether it is possible to use a large proportion of the energy generated on site to reduce energy bills from the grid. For example, a wind turbine and a heat pump is a good combination because the turbine output is highest during windy winter months and continues day and night, just when the heat pump is working hardest. Solar PV generates most on long summer days when houses use less energy, though business demands for energy remain. Battery storage or charging electric vehicles are possible ways of harnessing the energy.

 

If you decide against micro-generation, don’t forget that it’s still worth switching to an energy supplier that guarantees 100% renewable energy.