What I'm Seeing Now

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Are You Seeing This From Your Heat Pump?

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.

UNITS HAVE TO BE SIZED PROPERLY FOR THE VOLUME OF AIR THEY ARE TO TREAT.  IT SHOULD BE JUST RIGHT - NOT TOO LARGE AND NOT TOO SMALL.  SOME HOUSES NEED MORE THAN ONE SYSTEM.

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

www.jaymarinspect.com


Comment balloon 42 commentsJay Markanich • January 08 2014 02:49AM

Comments

Never had or used a heat pump.  My question to you is I hear it is more energy efficent than the standard heating/cooling units.  Is tht true? 

Posted by James Dray, Exceptional Agents, Outstanding Results (Fathom Realty) about 7 years ago

Think I'll check my furnace filter today. 

Posted by Lenn Harley, Real Estate Broker - Virginia & Maryland (Lenn Harley, Homefinders.com, MD & VA Homes and Real Estate) about 7 years ago

Good morning, Jay.... I can remember 20 years ago, condo units being built and heat pump installed...new england is not a good place for heat pumps.... they are very expensive to run and not efficient....they usually can't maintain an interior temp of 70 degrees with our blistering cold weather.... single digits out today.

Posted by Barbara Todaro, Previously Affiliated with The Todaro Team (RE/MAX Executive Realty - Retired ) about 7 years ago

Jay - Unfortunately, I have seen quite a few of these icebergs when going through communities... it's just another example of home owners not paying attention to the proper operation of their home.

Posted by AJ Heidmann ~ CRS, YOUR Alexandria & Arlington, VA Real Estate Expert (McEnearney Associates, Inc.) about 7 years ago

Knowing the capacity is HUGE ....and you can learn as you point out..it may not be HUGE enough !

Posted by Sally K. & David L. Hanson, WI Real Estate Agents - Luxury - Divorce (EXP Realty 414-525-0563) about 7 years ago

Jay - living in New York not had much experience with heat pumps.  But the point you made about replacing filters is very important.  I do it all the time in the summer so I do understand freezing up.  It is so easy to forget to change that filter.

Posted by Grant Schneider, Your Coach Helping You Create Successful Outcomes (Performance Development Strategies) about 7 years ago

Heat pumps are likely the most standard heating/cooling units in your area James.  They are cheaper than electric baseboard or resistance.  But not cheaper than gas.

That's the ticket Lenn.

Barbara - heat pumps today are entirely different than the units 20 years ago.  But in your area they would have a hard time.  It was 6F here this morning.

AJ - you are probably right.  Seeing so many is unusual.

S&D - sizing units is a very complex calculation, so your HVAC guy has to know what he's doing.

 

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Grant - I don't know exactly the line where the heat pump becomes less recommended.  But in New York I would think they are not the best way to go.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Hi Jay,

Many home owners let alone new home buyers for the first time don't have a clue as to how often to change the furnace filter.

I am having a post tomorrow about this subject.

Have a good day in Bristow.

Best, Clint McKie

Posted by Clint Mckie, Desert Sun Home, Comm. Inspection 1-575-706-5586 (Desert Sun Home, commercial Inspections) about 7 years ago

Clint - I tease people every inspection with the line I used in the post about monthly replacement.  I have furnace filter posts about once a year.  It is very important.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

you bring up a good point that is a big issue down here in Florida, Sizing. When the unit is too big yes it will cool down the house fast but it will not have time to remove the humidity.

Posted by Chuck Mixon, Cutler Bay Specialist, GRI, CDPE, BPOR (The Keyes Company) about 7 years ago

For that reason it is better to size an AC unit slightly too small Chuck.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Jay, Great post and an outstanding explanation of heat pumps. I have re-blogged it for some northern transplants who do not know much about their heating systems. IMHO as natural gas becomes more available here in the south, we will see the slow demise of the heat pump. It is warmer and cheaper. If I had gas available I would use it.

Posted by Tom Bailey (Margaret Rudd & Associates Inc.) about 7 years ago

Thanks Tom.  You might also appreciate this post:

http://activerain.com/blogsview/4193187/-so-which-is-cheaper-gas-or-electric-

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Good morning Jay,

We do not see many heat pumps in this area.

Make yourself a great day.

Posted by Raymond E. Camp, Licensed Real Estate Salesperson Greater Rochester (Howard Hanna Real Estate Services) about 7 years ago

Thank you!

Posted by Drick Ward Property Management / Broker Assoc, "RealtorDrick" - Experienced Representation (NEPTUNE REALTY) about 7 years ago

With good reason Raymond.  They work better when they are not covered with snow...

You are very welcome Drick.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Jay, haven't had any problems this year with the compressor freezing over. Of course heat pump efficiency is out the window with the cold weather we've been have the last couple of days.

Posted by Michael Setunsky, Your Commercial Real Estate Link to Northern VA about 7 years ago

Once a month? Geez, I better get to the hardware store today Jay. Probably should get some extras too, so they are handy in 30 days.

Posted by Tom Arstingstall, General Contractor, Dry Rot, Water Damage Sacramento, El Dorado County - (916) 765-5366, General Contractor, Dry Rot and Water Damage (Dry Rot and Water Damage www.tromlerconstruction.com Mobile - 916-765-5366) about 7 years ago

Everyone to Jays house this weekend 10-2 and bring a picture of your pump

Posted by Richie Alan Naggar, agent & author (people first...then business Ran Right Realty ) about 7 years ago

It is Mike, but pay attention to the filter too.

Tom - I use the washable filters from Allergold.  There are two philosophies on filters, but I prefer to keep my unit clean.  You have to be really dilligent about washing them.  I have had the same filters in my house for 15 years, at a cost of 3 cents per month.

'Mon over Richie!  We might get some football in too.  I have gas furnaces, by the way.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Jay, thanks for your explanation. Just about every home we show here in the Nashville area has a heat pump, as do we. The very cold weather we've been experiencing really makes for problems and very expensive use. As I understand it, when the outside air temp is this cold, as in the teens or less, the unit has a backup heater type element to assist getting to the desired temperature. Our heating costs really jump when it's this cold. Unfortunately, natural gas is not available where we live.

Posted by Tom White, Franklin Homes Realty LLC, Franklin TN (Franklin Homes Realty LLC (615) 495-0752 or www.FranklinHomesRealty.com) about 7 years ago

No natural gas where we are, either, but thank goodness for a wood burning stove (i.e., buck stove fireplace insert) - it heats the entire house!  Heat pumps in this cold just cannot keep up. 

Posted by Susan Haughton, Susan & Mindy Team...Honesty. Integrity. Results. (Long and Foster REALTORS (703) 470-4545) about 7 years ago

That is the perfect climate for them Tom.  My brother lives in Old Hickory.  A resistance furnace inside automatically comes on to aid the compressor when it can no longer derive heat from outdoors.

Susan - that is a great way to go if wood is cheaply available!  It's comfy heat!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

I can immagine there would be times of very low temperatures and high humidity where it might be quite difficult for the unit to keep itself free of frost.

Posted by Charles Buell, Seattle Home Inspector (Charles Buell Inspections Inc.) about 7 years ago

This caked ice means it isn't working properly to defrost once ice begins Charlie.  The day of that photo it was 35F, not really cold.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

It somehow looked like an Ousite unit for a centralized AC with all the ice and color now. Many people would still prefer a fireplace and wood. but HVACs can really be useful.

Posted by Michael Ha Elmhurst, Woodside, Maspeth (Rego Park, Forest Hills, Jackson Heights, Corona, Middle Village) about 7 years ago

I had a fireplace and wood post just a couple of days ago Michael!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Jay, Thanks for the link. I have re-posted that one also. I want my friends and neighbors who think we do not need natural gas here to read it.

Posted by Tom Bailey (Margaret Rudd & Associates Inc.) about 7 years ago

Tom - without even discovering more, or improving technology to get more out of where we have already harvested gas, we have enough for 120 years worldwide.  In that time frame other methods of energy will be developed.  At the turn of the last century, did anyone imagine nuclear?  Or even natural gas furnaces?

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Excellent post Jay, a few of my clients have heat pumps and I know nothing about them and want to understand them...are they really a huge improvement? 

Posted by Ginny Gorman, Homes for Sale in Southern RI and beyond (RI Real Estate Services ~ 401-529-7849~ RI Waterfront Real Estate) about 7 years ago

I don't have to worry about this issue, no heat pump for me.

Just because it's outside doesn't mean you don't need to do maintenance.

Posted by Suzanne Otto, Your Montgomery County PA home stager (Six Twenty Designs) about 7 years ago

Thanks for explaining how heat pumps work.  I see this in some listings and I had no idea how they work.

Posted by Joan Whitebook, Consumer Focused Real Estate Services (BHG The Masiello Group) about 7 years ago

We have a heat pump but fortunately not had it ice up.

Posted by Evelyn Johnston, The People You Know, Like and Trust! (Friends & Neighbors Real Estate) about 7 years ago

I have a heat pump. During the last few days I went out to look to see if that was happening. It was just too dang cold to stand there and look.

Posted by Bill Reddington, Destin Florida Real Estate (Re/max By The Sea) about 7 years ago

I have a heat pump. During the last few days I went out to look to see if that was happening. It was just too dang cold to stand there and look.

Posted by Bill Reddington, Destin Florida Real Estate (Re/max By The Sea) about 7 years ago

 Good morning, Jay. I have a dual fuel package unit and I hear going through its defrost cycle several times during the day.

Posted by TeamCHI - Complete Home Inspections, Inc., Home Inspectons - Nashville, TN area - 615.661.029 (Complete Home Inspections, Inc.) about 7 years ago

I dont' know what you mean by improvement Ginny, but as to the heat pump systems, yes there have been huge improvements over the years.

Suzanne - no matter what you have, it needs maintenance!

Joan - sometimes people think they have heat pumps and they don't! 

Evelyn - that means you are doing well with your filters and the unit is operating properly.

You could tell from the inside Bill, if it wasn't heating properly.  Defrost cycles are necessary - icing is not.

Michael - there is a different sound.  It can last from 10 - 30 minutes.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

I always felt that heat pumps up north did not work very well heating homes in the winter esp when it got very cold...

Posted by Edward Gilmartin (CRE) about 7 years ago

And you were right Edward!  They are not as effective.  Where very cold heating would be very expensive.

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

Interesting. I never thought about that. I am going to look at my unit tomorrow to see if there is ice on it. Thanks for sharing. 

Posted by Lisa Perry - NMLS # 276329, Northern VA - VHDA, 100% Loans - Jumbo Loans (FHA, VA, Jumbo, Downpayment Assistance, Conv.) about 7 years ago

You would have to catch it during the defrost cycle Lisa.  And your temps and humidity might not be such that ice can develop.  But check your filter!

Posted by Jay Markanich, Home Inspector - servicing all Northern Virginia (Jay Markanich Real Estate Inspections, LLC) about 7 years ago

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