Ground Source Heat Pumps

Welcome to Ground Source Heat Pumps: The Energy Efficiency Podcast – episode 7, the podcast that brings you a mix of energy efficiency news, products and tips all year round. We’re interested in profiling people and products involved in promoting energy efficiency habits, products and information, so please do get in touch if you have something to contribute.

Before we get on with our advertised features, the Guardian reported last week on the progress made towards hitting net zero by various local authorities in England. This is on the back of Labour leader Jeremy Corbyn urging local authorities to take a lead on reducing carbon emissions.

Progress varies wildly across the UK. This will inevitably reflect variations in population density and affluence around the country.

Stroud in Gloucestershire

Since the 1990s Stroud in Gloucestershire has taken this bull by the horns. In 2015 it became the first local authority in Europe to become carbon neutral. As well as undertaking domestic energy efficient retrofits it has fitted solar panels to houses and all municipal buildings. Residents are feeling the difference and spending less on energy bills.

Collaboration

Its grade II listed council building has secondary glazing and internal insulation and sources all heat from renewables. Through collaboration with other local authorities Stroud has boosted recycling rates to 61%.

It has plans for more. It wants to become a carbon neutral area by 2030, 20 years ahead of the government’s target. It will do this by using electric vehicles, making all homes (that’s ALL homes) energy efficient, using low- to no-carbon electricity and heat generation and tree planting. It’s aiming to facilitate cycling, walking and renewable-powered public transport. At this rate Stroud will also become one of the healthiest local authorities in England.

Simon Pickering, a Green party councillor and chair of the council’s environment committee, makes the point:

“It will no longer be business as usual to cut the energy use of all buildings by at least 80%, generate over half the district’s electricity needs from renewable sources and transform how we travel.”

And this is the point, serious policy shift must be implemented by an authority wanting to see results.

However Stroud and other authorities including Nottingham and Oxford are the bold few. Despite widespread announcement of climate crisis among local authorities in the UK many take an illogical approach to carbon reduction. Manchester’s plans for carbon neutrality explicitly exclude emissions from aviation. In Norwich and Hereford there are road-building plans. In Hereford in particular these plans have been heavily criticised for not tackling the real cause of congestion – short city centre journeys that could be replaced by public transport or walking and cycling infrastructure. Going even further, Cumbria County Council has approved opening a new coal mine. This is another example of the postcode lottery at work in the UK.

Ground Source Heat Pumps

Heat pumps are used in about 100,000 homes in the UK. In Sweden, Germany, Switzerland and the USA they’ve been widely used for years.

Underfloor heating going in

Ground source heat pumps (and their near relations air and water source heat pumps) have become the heating method of choice for low-energy builds. This is for two main reasons. Firstly, although they need electricity to run, the heat the pumps draw in is continually and naturally renewed. Secondly, heat pumps work best in a house with levels of insulation and draught-proofing well above average. Due to its lower temperatures a heat pump system tends to work best with under-floor heating and warm air heating systems.

How it works

The temperature a couple of meters below ground stays at around 8-12 degrees all year round. A ground source heat pump extracts this heat through buried loops of pipe about 100m long. The pipe has a mix of w