Are You Seeing This From Your Heat Pump?

Real Estate Agent with Margaret Rudd & Associates Inc.

This is a great explanation of a heat pump for my friends from the Northeast that have recently moved to the South. The blogger is an outstanding home inspector.

Original content by Jay Markanich 3380-000723

It's been cold here lately and when it gets real cold are you seeing this from your heat pump?

Does it look like an ice cube?

A heat pump is essentially an air conditioner that can work backwards!

In winter months many heat pumps will have to put themselves through what is called a "defrost cycle."

During the heating season, a heat pump will compress heat from outside and transfer it indoors. 

When the air outside is very cold, it will freeze on the heat exchanger when the fan is blowing air over it.  The purpose of the defrost cycle is that when the unit recognizes that the ice is forming the unit will work to eliminate it.

When ice builds up on the outdoor unit, air cannot flow through it.  This can reduce efficiency dramatically and can even damage the unit.  The defrost cycle should eliminate icing before it has a chance to build up.

How often the unit goes through the defrost cycle depends on many things - outdoor temperature and humidity, the condition of the system and the amount of indoor heat it is expected to provide.


There are sensors on the outdoor compressor unit that tell it when it's temperature has risen enough to turn off the defrost cycle.  This can take a while, even 30 minutes or so.  Also, if the cycle is not stopped by these sensors defrosting will continue for about 10 minutes.

If your heat pump is not providing adequate heat it can be because:

  • it was not installed correctly,
  • or is undersized for the load it is expected to carry,
  • or maybe the filter needs to be changed
  • or the unit is surrounded by bushes or plants and not getting adequate air flow.

If ice build up is sudden you may be in need of a service call, or other maintenance.

During periods of frequent use, do you know how often once a month you should replace your furnace filter?

Yes!  About once a month!

My recommendation:  regular maintenance may reduce the frequency and longevity of the defrost cycle.  Reducing the load the unit is expected to handle, like not raising indoor thermostat temps really high, or adding extra insulation into the attic space, will go a long way toward saving money and increasing the life span of the system.  Good windows and doors, and good window shades and curtains, will also help reduce the heating requirement the system is expected to handle.  Bottom line:  maintain your system and use it properly.



Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560

Comments (3)

Barbara Todaro
RE/MAX Executive Realty - Happily Retired - Franklin, MA
Previously Affiliated with The Todaro Team

Good morning, Tom....Happy New Year.... this is a great post to reblog...

Jan 07, 2014 10:29 PM
Tom Bailey
Margaret Rudd & Associates Inc. - Oak Island, NC

Barbara, We have a new agent that just moved here from Connecticut. She went on her first showing a few weeks ago and came back asking what a heat pump was. I posted this for her and all the other transplants we have here. We have limited natural gas (my favorite) so heat pumps are everywhere. 

Jan 08, 2014 05:11 AM
Debe Maxwell, CRS | The Maxwell House Group | RE/MAX Executive | (704) 491-3310 - Charlotte, NC
The right Charlotte REALTOR!

Interesting explanation, Tom!  Funny but, my buyers today, when meeting with the home inspector, asked the difference in the gas packs and the heat pump.  They are buying a home with 2 gas packs and 1 heat pump and the inspector said that he was a big fan of the heat pump.  Like you though, I'm a gas fan but, it sounds like the heat pump is a great alternative.

Jul 30, 2014 01:45 PM