Winter is on its way in the northern hemisphere and with rising gas prices across the globe, we think the obvious question is what’s the most environmentally friendly way to heat your home? It seems that air source heating or ground source heating (or geothermal heating) are the most environmentally friendly ways to heat your home. Here is why.
Table of Contents
- Hydronic heating system
- Central air heating
- What is forced air heating?
- Air source heating
- Ground source heating
- Electric heating
- The most energy efficient and sustainable way to heat your home
Hydronic heating system
Most UK homes with a boiler will be familiar with a hydronic heating system. Gas central heating is in 95% of homes in the UK, in around 23 million homes. It uses natural gas which results in high carbon emissions. The UK government plan to reach net zero by 2050 means that this type of boiler is now banned from being installed in new homes (EDF).
A hydronic heating system uses a gas boiler to heat water for hot water use and also to heat radiators around the house by circulating the hot water. Hydronic heating systems are healthier than forced air heating systems because they are closed units.
Central air heating
Central air heating will be familiar to U.S. homes with HVAC. It is a standard HVAC furnace system where the furnace heats the cold air from your home. This is then circulated around the home through the ducts and vents (Trane).
Furnaces are fueled by gas, electricity or fuel oil like propane. This means that gas and fuel oil furnaces are getting more expensive to run as prices rise. Unless they are electric and run on renewable energy, this also uses fossil fuel and results in carbon emissions.
What is forced air heating?
Forced air heating is any heating system that sends heated air through ducts and vents around the house. So this applies to ground source heating, air source heating, and hydronic forced heating; where the air is circulated around the hot water coils to heat it before being circulated through the ducts and vents in the house.
According to Masters Heating and Cooling Inc, forced air heating is difficult to retrofit as it requires ducting. It is easier to fit into a new home or a home that already has ducting. There are also concerns about allergies, as forced air heating can circulate dust and mold that is not picked up by filters. On the plus side, forced air heating is inexpensive and quick to heat a home.
Air source heating (using an air source heat pump)
Air source heating uses external air to circulate heat around the home (Which). An air source heat pump draws heat from outside the home and it is absorbed into a liquid refrigerant. The liquid is then compressed to increase the temperature before it is condensed to release the heat from the liquid. The heated water is now sent to underfloor heating and radiators. It can also be stored for hot water. An air source heat pump is sometimes called an air-to-water heat pump as it circulates heated water not air.
Air source heat pumps use electricity to run. Here’s the bad news. Although air source heat pumps are sustainable if using renewable electricity supply, they cost more to install and more to run than a new efficient gas boiler. This choice would definitely be an investment in green technology for the sake of the planet. The same applies to a ground source heat pump.
Ground source heating (using a ground source heat pump)
Ground source heating uses heat from underground or geothermal heat to heat your home. Refrigerant or antifreeze is circulated around pipes that are buried underground which warms up the liquid. The liquid is then transferred into your home. It goes through a heat exchanger which transfers the heat to water in the heating system, which warms your home. We’ve written an article about geothermal heating that goes into more depth.
Ground source heating, like air source heating, requires electricity to run it. The electricity needs to be sourced from a renewable source if it is to be sustainable. As with air source heating, a ground source heat pump costs slightly more to run than an efficient gas boiler and the costs for installation of the pump and the piping are significant.
Electric heating, if using a renewable energy supplier or a solar panel system to provide your own supply, is possibly the cleanest way to heat your home. There are no carbon emissions and like most electrical items, you can recycle electric heaters at your local recycling center.
Installation costs are lower than air source or ground source heat pumps but electrical heating costs by far the most to run annually. According to a study by the Energy Saving Trust in the UK some time ago, around four times the cost of a gas boiler or a heat pump.
The least costly, most sustainable method of heating your home is likely to be solar panels for electric heating at a cost of around £6,500. Compare this to install costs of around £10,000 for air source and £24,000 upwards for ground source heating. Plus with heat pumps there are electricity running costs.
The most energy efficient and sustainable way to heat your home
There is much to consider when you are thinking about an energy efficient and sustainable way to heat your home. Choosing a home heating system depends on whether you can afford to fund new technology that is more sustainable or whether you are looking for the most energy efficient system to save money.
Installing solar panels is the most energy efficient and sustainable way to heat your home, based on costs. While air source and ground source heat pumps are more sustainable than HVAC or gas central heating, they are costly to install and run.