Green energy systems

Solar hot water panels

There are two main types of solar collector:

  1. Flat plate – each panel is typically 2-3m2 panels with flat-glazing which can be mounted either on, or in, a roof. PV powered pumps are available with flat plate systems to reduce the need for power from the grid.
  2. Evacuated tubes – comprising a number of “vacuum tubes” fixed into a manifold mounted onto a roof. Highly insulated pipes are routed from the collector(s) to either the existing, or new, hot water cylinder. Cold water from the bottom of the insulated hot water cylinder is then pumped thorough the solar collector where it is heated before flowing into the top of the hot water store.

Solar heating systems currently qualify for financial help from the government under the ‘Renewable Heating Incentive Scheme’ – this gives you money in return for using renewable energy to heat your home. Unfortunately the government has recently cut this tariff which reduces the incentive to purchase a system.

Heat pumps

A recent growth area in electrical heating is ground, air and even water source heat pumps. They can be up to 300% more efficient than a conventional boiler.

Ground Source Heat Pumps

These systems can be used to:

  • Heat radiators.
  • Provide heat for underfloor warm air heating systems.
  • Heat hot water in your home.


  • No fuel deliveries needed.
  • Minimal maintenance required.

Ground source heat pump diagram

Air Source Heat Pumps (ASHPs)


  • In comparison to ground source heat pumps they are easy to install.

Depending on the type of system you install, this heat can then be used:

  • To heat radiators.
  • Provide heat for underfloor heating systems.
  • To warm air which is circulated using fans.
  • To heat water in your home.


  • No fuel deliveries needed
  • Minimal maintenance required
  • Easy to install
  • Some can be used for air conditioning in the summer

Air source heat pump diagram



  • Wood is often used as an additional or secondary fuel in a home – either burnt in a solid fuel stove or a traditional open fire heating one room at a time. Alternatively, you can invest in a large biomass boiler, connect it with the hot water tank and radiators and use it for centralised heating.
  • Wood chip is also available for use in domestic boilers, where an auto-feed facility can provide heat lasting for a few hours.


  • One of the advantages of solid fuel is that it if there is a power cut or a supply failure you will not be affected because you are not reliant on the energy suppliers. However, you do need to ensure that you are always stocked up.


  • Biomass as a fuel consists mainly of wood. Wood is a low energy density fuel – which means there is less energy from a greater quantity – so a lot of storage space is needed if you have a biomass boiler.

Biomass burner diagram.

Solar gain


  • Concrete or tiled floors will need to be insulated below the surface and walls will need to be solid, rather than stud partition. They will also need to have the brickwork or concrete exposed, or at most have plaster directly over the brickwork or concrete. In most homes plasterboards have a gap behind them, which unfortunately reduces the wall’s effectiveness as a ‘thermal store’

Solar gain diagram