Each house has a list of the main 'eco' features on its page. This is a brief guide to the features demonstrated by the houses as a whole.

See a features table showing which houses have which features:

features table link


Eco Open Houses features

Airtight construction - The method of making new or refurbished buildings highly airtight to minimise ventilation losses; often associated with MVHR.

Biomass boiler - Boiler fuelled by largely carbon-neutral wood, normally as pellets, but can also be chips or logs.

Condensing boiler - A type of boiler that captures more usable heat from its fuel. Its efficiency is made possible by the design of the condensing boiler’s larger (or dual) heat exchanger. Most modern boilers are condensing boilers.

Draughtproofing - Lots of heat is lost through draughts so this is a priority for saving money. Typical draughty areas of a house include chimneys, loft hatches, windows and doors, around skirting boards and floors.

Energy controls - Heating systems with simple controls in an accessible place can be more efficient as people are more likely to use them. Typical controls include thermostatic radiator valves for each radiator, room thermostats – and programmers, which enable more control.

Flue gas heat recovery (FGHR) - Even a condensing boiler vents useful heat in the flue gas, but this can be recovered to preheat water using a simple FGHR unit.

Green roof - A roof that is partially or completely covered with vegetation and a growing medium, planted over a waterproof membrane.

Grey water recycling - Collecting waste water from sinks, showers and baths and reusing it for toilet flushing or watering the garden. Grey water is waste water that has not been mixed with sewage.

Ground floor insulation - For suspended floors, mineral wool or rigid insulation boards are installed between beams. For solid floors, rigid insulation board is placed on top of the solid floor and under a finishing layer. Installing thicker carpets and/or insulated carpet underlay may also help reduce draughts.

Heat pump - A heating unit that extracts heat from the external environment, e.g. air or ground, and uses it to heat a building. The pump uses electricity to power it.

High performance glazing - Windows that are designed to minimise heat loss, for example through an insulated frame, a low E coating, an inert gas filled cavity, triple glazing, or any combination of these.

LED lighting - A very low energy form of lighting (light-emitting diode) which uses significantly less energy, is long-lasting and cheap to run. LEDs are now available for most light fittings.

Low energy appliances - All appliances are rated from A to G, with appliances rated A and A+++ for refrigeration using the least energy. Washing machines and dishwashers are also rated for the amount of water they use per cycle.

Low water goods - Taps, showers or toilets that are designed to use less water than typical plumbing fittings, typically by aerating the water.

Mechanical ventilation with heat recovery (MVHR) - A ventilation system with a heat exchanger that recovers warmth from outgoing air to warm cooler incoming fresh air. This requires a high level of airtightness to be effective.

Natural materials - Products that comes from plants or animals – including sheep’s wool insulation, sweet chestnut cladding, sustainably sourced timber paints and clay plaster. Natural materials tend to be more sustainable than artificial materials and allow breathability and movement of moisture.

Passive solar design - Careful design using building orientation, solar gain, super insulation, thermal mass and passive ventilation. It can take advantage of the sun’s energy and internal gains from cooking and other activities to reduce the amount of heating required.

Passivhaus standard - A low energy standard that reflects the principles of high levels of insulation, airtight construction, high performance glazing and a mechanical ventilation system with heat recovery.

Photovoltaic (PV) panels - Panels usually mounted on a south-facing roof that convert sunlight into electricity. Electricity generated using PV panels attracts a payment known as the Feed in Tariff (FIT).

Rainwater harvesting - Collecting water that falls on a roof and using it at home for washing clothes, flushing a toilet or watering the garden.

Solar thermal panels - Using the sun’s energy to directly heat water. Can be a flat plate system or evacuated tube system. From 2014, the Government plans to introduce the Renewable Heat Incentive, which will give payments for solar heat.

Solid wall insulation (SWI) - Solid walls can be insulated externally or internally. Walls are usually insulated externally by fixing insulation boards to the wall and then finished with rendering or cladding. Walls are internally insulated by fixing rigid insulation boards to existing walls or by building a stud wall filled with mineral wool or equivalent which is then dry lined with plasterboard.

Timber frame - Type of wall made from timber studs, finished with dry lining boards on the inside and cladding outside, creating a void that is easy to fill with insulation.

Woodburning stove - A simple measure that can substitute low carbon heat from wood for a large proportion of fossil fuel space heating.

heat loss

How a house loses heat



Domestic carbon emissions

Source: DEFRA