California Association of Building Energy Consultants

Electric Heat Pumps vs. Gas or Propane Heaters

I recently received this question from a client:

We are considering an electric heat pump to offset the amount of propane we will use to heat the house. What are your thoughts and do you have any suggestions?

This is an interesting question and you are likely to get many opinions. Here is my opinion (based on personal experience and being married to an HVAC contractor for 33 years!).

Heat pumps use only electricity and in the winter use additional electric resistance heat when the temperatures are cool outside. This is very costly. Also, when the outside air temperature is in the 40's or so, the heat pumps have a hard time keeping up with the heating demand required to heat a home comfortably. Heat pumps will run much longer in the winter to try to heat the home and can shorten the life of the equipment.

I stated that the heat pump is costly to run. However, if the electricity is produced from solar power that is not the case. Yet, in the winter cold months the question is, "Will the solar panels be able to produce enough electricity in the dark winter months to heat your home, especially in the area in which we live?" Since solar is still just emerging there is not enough data to prove its effectiveness over time.

In the case of a gas forced air system (which uses gas and electricity) the amount of heat is directly based on the number of BTUh's of the furnace. For example a 90% AFUE rated, 100,000 BTUh unit will blow in 90,000 BTUh when the thermostat calls for heat. This makes the time taken to heat the house to a warmer temperature much less than with an electric heat pump. The unit will turn off sooner and save on the lifetime costs of the equipment.

These thoughts have been the standard for many years, and yet, there is always room for different ideas.

If your choice is to install electric heat pumps for heating and air conditioning, then a suggested water heater choice is an electric heat pump water heater. For some information about an electric heat pump water heater from the Energy Star website, see Water Heater, Heat Pump for Consumers.

Also, any system that is not installed according to the mechanical and energy codes will not provide adequate heating and cooling for your home. Insist on a well-installed system.

Just another fact for you to know … the entire California Energy Code is written against the use of electricity.

As always, I am available to discuss the process of meeting the California Energy Code for any building project. Contact me …