Air-To-Water Heat Pumps

-. What are air-to-water heat pumps?

-. Air-to-water vs. Air-to-air heat pump

-. Gas boiler ban & heat pump rebates

-. Heat pump application examples

-. Things to consider with heat pumps

What Are Air-To-Water Heat Pumps

Air-to-water heat pumps vs. Air-to-air heat pumps (Mini splits)

Pros of Air-to-water heat pumps

  1. Use water (4.2 Joules/gram)

  2. Heat conducted by air; more comfortable dwelling space

  3. Could be used cheap thermal battery

  4. Efficient/convenient for floor heating systems

  5. Consistent temperature

  6. Efficient air movement in a space, especially with hybrid radiant heating/cooling systems

Cons of Air-to-water heat pumps

  1. Expensive in a short run

  2. Relatively bulky

Pros of Air-to-air heat pumps

  1. Cheap in a short run

  2. Relatively compact

  3. Very good at cooling

  4. Dehumidifies air

Cons of Air-to-air heat pumps

  1. Use air (0.7 joules/gram)

  2. Still need a water heater for DHW

  3. Temperature varies

  4. Inefficient air movement in a space

  5. Noise

  6. Dry air; dry skin

  7. On-demand operation; no thermal battery

Gas Stove Ban

From year 2019, many California cities, such as San Francisco, Oakland, Los Gatos, and Sunnyvale, had banned new gas boiler installation, especially in a new building. By cooperating that ban, cities try not to give permits for installing gas stoves.

Heat Pump Rebates

  • High-efficiency heat pumps and mini splits are eligible for a federal tax credit up to $2,000.

  • Larger federally funded rebates might become available in 2024, though they may not be easy to claim.

  • A California statewide rebate of $1,000 is available, up to two systems per household.

  • Many utility companies in California offer further rebates for heat pumps, ranging from $100 to $3,000.

  • You can generally stack or combine federal, state, and local heat pump incentives.

* Any energy-saving and carbon-free systems must be installed by certified/licensed installers for federal, state, local governments rebates.

Heat Pump Applications

The figure represents an example of air-to-water heat pump installation that is suggested by a heat pump company. As known, heat pump plumbing looks complicated. So there are some hydronic modules that combines plumbing and piping into a module. With those modules, installing heat pump could be complicated. Many researches have reported that floor heating combined with fan coils is an efficient application with air-to-water heat pumps.

Most quality heat pumps will provide 55°C with ease and some higher temperature units can produce as high as 70°C (at a reduced efficiency of course).  55°C is certainly hot enough for domestic use. However, A DHW(Domestic Hot Water) tank that is a kind of electric boiler shall provide continuous hot water to your facets.

Water is evaporated normally at 100 Celsius. So fan coils working with heat pumps does not make room dry, unlike traditional hot air handler. It yields gentle breeze.

Things To Consider With Heat Pumps

  • The higher the seasonal performance factor (SPF) of a heat pump, the more efficiently it will produce heat using electricity

  • Modern air-to-water heat pumps with inverter technology can modulate their heating output. This means that they only produce as much heat as your home currently needs, which reduces the amount of electricity consumed by the air source heat pump and lowers the cost of operation and heating.

  • ust like washing machines or fridges, heat pumps must feature an energy efficiency label issued by the European Union. Make sure your appliance has an A+++ label.

  • Some refrigerants used in heat pumps are potent greenhouse gases with an effect that is many times stronger than CO2 if they leak into the ambient air. The refrigerant R290 is a climate-friendly and natural alternative.