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

Only in some cases

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]}

Research needed for this sectionResearch needed for this section

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

Refrigerant chemicals

^{[QUANTIFICATION needed]}

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

• Heating
• Map of electricity by source