Heat pump
An electric heat pump is one way to heat a building. It works a lot like air conditioning but in reverse: The hot air goes indoors; the cold air goes outdoors.
Energy efficiency
Heat pumps can be more energy-efficient than electric heaters. But this efficiency gain disappears when the outdoor temperature is cold enough.[QUANTIFICATION needed]
Worse: When electricity is generated by fossil fuels, electric heating has up to 3 times the carbon emissions of just burning the fossil fuels directly in a natural gas furnace [see why]Most coal or natural gas power plants are only 33% efficient. They work by boiling water and driving a turbine.Exception: Newer "combined cycle" natural gas power plants can get up to 60% efficient. But for heating homes, that's still less efficient than burning the natural gas at home.
Also note: Electricity has losses in transmission too (power lines) - typically about 5%. . Heat pumps are almost never efficient enough to make up for this.
Maybe it's worth getting a heat pump if you live in an area where winters are moderate and electricity is generated mostly by renewables or nuclear.[WORLD MAP needed]
Can be a case study or generalized statistics
- Need graph: Heat pump efficiency vs outdoor temperature.
- Life cycle analysis
- How much energy does it typically take to manufacture and install a heat pump?
- How often (if ever) is it viable/worthwhile to repurpose an air conditioner in the winter, to help with heating?
- Are there any "reversible" heat pumps that can work for both heating and cooling? (why)~ Manufacturing half as much stuff would certainly reduce life cycle emissions.
~ Use cases:
- - ~ New construction
- - ~ Any time someone has to replace their air conditioner anyway
- - ~ Any time someone has to replace their heating system anyway, and doesn't already have an air conditoner but could use one
- Are there any "reversible" heat pumps that can work for both heating and cooling? (why)~ Manufacturing half as much stuff would certainly reduce life cycle emissions.
Refrigerant chemicals
Because of how heat pumps work, they must contain a substance known as a refrigerant. Most refrigerants in use today[ELABORATION needed] happen to be potent greenhouse gases. They aren't supposed to leak out into the atmosphere - but they sometimes do, if the heat pump gets old or is disposed of improperly.
This section is incomplete. It needs:
- Quantification
- How much of climate change is due to refrigerants?
- How much worse would it be if we all used heat pumps to heat our homes?
- How does this compare to the status quo of heating (often natural gas)?
- Solutions
- Are there any alternatives - refrigerants that aren't greenhouse gases? And are there tradeoffs? [new page needed]
See also