The AC Doesn't Work; The Heating Doesn't Work - What's The Problem?

Home Inspector with Jay Markanich Real Estate Inspections, LLC 3380-000723

If the thermostat is fine, the circuit breaker is on, there is electricity to the house and the AC doesn't work; the heating doesn't work - what's the problem?

Glancing into the return in the hallway might lend a clue.

We have many years of dust build up.

Now, people think this is because they don't use a good air filter in the HVAC unit, or replace/clean it enough, or whatever.

The problem in this photo is from general dustiness in the house.  If the house isn't vacuumed often, or dusted, dust happens and the dust floats easily.  Of course it will move with air and if air is being sucked into the HVAC returns the dust will accumulate over time.

Dustiness in the house has little to do with the HVAC filter!


When you see this kind of build up keep in mind, it is not simply "dust."  It also contains millions, billions probably, of living organisms.


What did I expect to find inside the HVAC unit, in this case a heat pump?

More of the same!

Predictably this filter (the washable kind) was so clogged the screen had been getting pulled into the unit.

The electric panel board and the blower inside were similarly caked with dust.

The house is 29 years old.  This is the "replacement" heat pump and is only six years old!

I really don't know how long a heat pump can last without a filter being changed, but could this filter have six years worth of dusty build up?

In the past I have seen the cheap, cardboard filters so caked and the unit actually tried so hard to get air that it collapsed the filter right into the blower!  Not in this case however.  This filter has a plastic frame and isn't that easy to collapse.

One of my (silly) jokes that I grace clients with on home inspections is, "How often once a month should you replace or clean your filter?" 


There might be a month here and there when the system isn't used much and the filter does not need replacement.  But once a month is a great rule of thumb!

My recommendation:  while my joke may seem silly, it is intended to be instructive.  Clients don't forget it!  Truly, not cleaning the house and not replacing/cleaning the filter can be an HVAC system killer!  Then, when the system doesn't fire up during a home inspection, the inspector won't have to say, "I think it died from choking on dust!  It needs to be looked at by a licensed professional..."  Well, that guy is in for a good pay day!



Posted by

Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

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


Re-Blogged 3 times:

Re-Blogged By Re-Blogged At
  1. Wallace S. Gibson, CPM 09/18/2012 08:29 PM
  2. Aaron Silverman 09/18/2012 09:28 PM
  3. Evelyn Kennedy 09/19/2012 08:27 AM
ActiveRain Community
Virginia Prince William County Bristow
Ask the Home Inspector
Professional Home Inspectors
Addicted to Active Rain
Adventures in Home Inspecting
WeBlog Anything (almost)!
furnace filters
heat pump
air filter
dust control

Spam prevention
Show All Comments
Aaron Silverman, Bluewater Property Management, LLC and Lowcountry Turnkey Properties, LLC - Charleston, SC
Improving Real Estate Experience through Education

Good information.  That is why I change the filters when I conduct properties inspections.  The HVAC is too valuable to leave it up to the tenants.


Sep 18, 2012 09:28 PM #13
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Aaron - that is a very smart practice!  It's a cheap way to maintain things, like the oil in your car.

Sep 18, 2012 09:29 PM #14
Ginny Gorman
RI Real Estate Services ~ 401-529-7849~ RI Waterfront Real Estate - North Kingstown, RI
Homes for Sale in North Kingstown RI and beyond

Excellent tips Jay, so it has nothing also to do whether you have gas or oil heat?  I am asked that and have forgotten to get an answer?  thanks

Sep 18, 2012 09:47 PM #15
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

No matter Ginny.  They both pull and push air the same way!  A boiler heats and moves water, so there is no blower involved.

Sep 18, 2012 09:54 PM #16
Michael Setunsky
Woodbridge, VA
Your Commercial Real Estate Link to Northern VA

Jay, it's easy to forget about the return air duct. How often should the ducts be cleaned out?

Sep 18, 2012 09:55 PM #17
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

I don't know Mike.  For lack of a better word, when they look dusty.  A layer of dust affects air flow, so it does affect efficiency too.

Sep 18, 2012 10:00 PM #18
James Dray
Fathom Realty AR LLC - Bentonville, AR
Exceptional Agents, Outstanding Results

Morning Jay congrats on the feature.  You can see where the dust is being caked up on the wiring behind the filter.  Never did like those.  What is you recommend?

Sep 18, 2012 10:14 PM #19
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Thanks James.  Since the system did not work all I could do was recommend a professional to evaluate it.

Sep 18, 2012 10:27 PM #20
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

It's ironic that a several thousand dollar system can be ruined by simply not changing a part costing a few dollars. 

Sep 18, 2012 10:35 PM #21
Michelle Francis
Tim Francis Realty LLC - Atlanta, GA
Realtor, Buckhead Atlanta Homes for Sale & Lease


Great advice to avoid extra expenses of replacing a system EARLIER than needed with lack of maintenance.  While I agree once a month is awesome, at least having a plan and making it happen every three to six months keeps you on track.  Just like Wallace, we have our property management homes services routinely spring and fall to keep them going strong.  (It's the first phone call we will get when they are not working, so makes sense to keep the AC and Heat working well.)

All the best, Michelle

Sep 18, 2012 10:44 PM #22
Scott Seaton Jr. Bourbonnais Kankakee IL Home Inspector
SLS Home Inspections-Bradley Bourbonnais Kankakee Manteno - Bourbonnais, IL
The Home Inspector With a Heart!

Not a whole lot of working moving parts in the HVAC units. But the ones that do move, need to be able to move smoothly all the time. An annual tuneup and monthly filter change will help a unit work almost forever, at least until the inspector leaves.

Sep 18, 2012 11:28 PM #23
Bruce Kunz
C21 Solid Gold Realty, Brick, NJ, 732-920-2100 - Howell, NJ
REALTOR®, Brick & Howell NJ Homes for Sale

Good story, Jay. As inexpensive as the filters are, it's hard to believe we (including me) forget to change them often. It's on my list for this weekend!


Sep 18, 2012 11:40 PM #24
Richie Alan Naggar
people first...then business Ran Right Realty - Riverside, CA
agent & author

I just replaced a blower on a AC unit recently....I learned that there are only so many working parts and things to check when the unit doesn't work...out of those things, the filter was a relevant point....Good post..."Start your day with JAY"

Sep 19, 2012 12:07 AM #25
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Jim - I think the system froze up and fried.  But I simply recommended that a pro say that!

Michelle - it certainly depends on the filter, and there are a couple filter philosphies out there.  But once a month cannot fail.

Scott - here is the blower fan, one of those moving parts!  Had to kind of stick the camera back there, so it isn't the best o' photos.

Bruce - get on it and get back to the rest of us!

Thanks Richie.  And when the blower fan gunks up it can fail too!


Sep 19, 2012 12:41 AM #26
Gary Frimann
Eagle Ridge Realty / Signature Homes & Estates - Gilroy, CA
REALTOR and Broker

Jay, another fine report!  I agree with Richie above "Start you day with Jay".  I always look forward to your perspective and what yu discover.  Valuable information.  Now I'm off to get some new filters before I need to start my heaters.

Sep 19, 2012 12:48 AM #27
Bill Gillhespy
16 Sunview Blvd - Fort Myers Beach, FL
Fort Myers Beach Realtor, Fort Myers Beach Agent - Homes & Condos

Hi Jay,  I love the pics, the advice and the corny joke !

Sep 19, 2012 01:25 AM #28
Chris Smith
Re/Max Chay Realty Inc., Brokerage - New Tecumseth, ON
South Simcoe, Caledon, King, Orangeville Real Esta

Jay, in the past, in my first home, I went a year and a half without changing my filter.... in the summer my air conditioner stopped working, it was iced up outside... we tracked it down to the reduced airflow from the dirty filter... I now change my filters every month

Sep 19, 2012 02:07 AM #29
Goran Utvic
606 Homes LLC | Chicagoland Brokers Inc, Chicago IL 60656 - Chicago, IL
We Buy & Sell Chicago Houses Fast

Wow I can't believe someone would let it go so long without changing the filter. I disagree with how often you should change the furnace filter though...I say 6 times every half year ;)

Sep 19, 2012 05:41 AM #30
Evelyn Kennedy
Alain Pinel Realtors - Alameda, CA
Alameda, Real Estate, Alameda, CA


WOW!  That is a lot of dust.  I hate to see my filter.  Oh, I don't have air conditioning.  Another chore I don't have to deal with.  Great blog with good pictures.

Sep 19, 2012 08:22 AM #31
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Thanks Gary and I'm glad you do!  Your furnace will smell funny for a while after you first turn it on.

And thank you Bill.  Corny maybe, but the people remember it!

Chris - you tracked it down to exactly the right thing.  Lesson learned, almost the really hard way.

Goran - six of one and half a dozen of the other!

It is Evelyn.  The pictures make it entirely understandable.  And thanks for the reblog!

Sep 19, 2012 09:52 AM #32
Show All Comments

What's the reason you're reporting this blog entry?

Are you sure you want to report this blog entry as spam?


Jay Markanich

Home Inspector - servicing all Northern Virginia
You may contact me anytime...
Spam prevention

Additional Information