on Aug 02, 2011

Has anyone had their evaporator coil on the HVAC unit cleaned?

I am not talking about the outside condenser, but the coil, typically A shaped, on top of the furnace.

Here is my reason for the question - my HVAC unit is ~25 yrs old, the outside condenser is ~10yr old. I recently dropped the fan out of my HVAC unit and cleaned the 'air scoops', which were super nasty and FULL of dirt. With this said, I can only imagine that the air pushed up into the coil up to this point has been extremely dirty, clogging the coil / reducing the volume of air / reducing the efficiency.

Any thoughts?

19 Comments

Paul M Fairburn, GA

It is suggested that the evaporator coil be cleaned once a year but if it is like the old one I just got rid of I don't know how you would do it since the entire coil is sealed in its compartment and covered by the heat exchanger on the other side. You would think that someone would have left some sort of access for maintenance but I think that most are like mine and impossible to get to. The new one I have has an access panel and it is easy to get to. I also think that if a high quality ...»
air filter is used and it is changed in a timely fashion that the evaporator coil will pretty much stay clean. That is the purpose of the air filter, to protect the evaporator and the duct work. Keeping the household air clean is a by product of protecting your equipment.

on Aug 02, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

If your properly maintaining the filter system and your return duct system is sealed tight so no air bypasses the filter then you should only need to clean this coil every five years of so. If you have a high efficency HEPA filter installed, then you should never need to clean this out.
Based on what you said about cleaning the fan you should consider getting the coil cleaned. This is not typcally a home owners type of project as the pipes going to and from this coil are easly ...»
bent and are under very high pressures. The HVAC contractor has special foaming coil sprays that they use to flush out the dirt between the fins.
Once done and the system is put back into service the contractors should check the charge on the system as it may have ben altered due to the past lack of air flow that occurs due to plugged coils.
Did you know that just a 1/16th amount of dirt on the fan blade edge can drop the air flow by almost 20%! So cleaning this fan did a lot for your system and for your energy savings when the system is running.

on Aug 02, 2011 · Like 0
Victor R

Woodbridge - some local AC guys I spoke to mentioned that cleaning the scoops / fan should be a big improvement. While i consider myself handy, this is for sure out of my league.
Paul - I am with you, cleaning the fan was a big enough project for me. As you mentioned there is no access to the coil. I currently have a local company coming by next week to take a look at it and give me a cost. ...»

I can only imagine that it is SUPER nasty based on what I found in the fan and having no idea of how the previous home owner took care of the unit.
Unfortunately, the unit has a very poor filter system or lack there of due to age. Right now I can only fit in the 1/2 filters and have to be boards / bricks to hold it in place.
I was just wondering if anyone was in my situation, had the coil cleaned, and if they noticed any significant improvement in air temps / cost to operate. I am told the service may run in the $300 range and was trying to figure out if it is worth the $$.

on Aug 03, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

Well if you do not do the cleaning, your wasting money on electric bill as the system has to work harder to push the air through the coil. Three hundred sounds about right on cost.
It is very important that you get your return duct system sealed as best as you can. If the return is out of the conditioned space, your cooling and removing moisture from another location which lowers the efficiency of the system and your comfort on the very hot days that seem to be gripping ...»
our nation.
Sealing the system is not to hard. You can use over the counter products such as caulk and metal foil tape. The more you seal the more you will save.
I recently did a energy audit on a home in NJ. The client had a 9 year old AC system we did a manual J calculation to check the sizing of the system and it was almost 12,000 Btu's over sized. The client said they had that size unit put in because they were never getting the house cool until they put this system in. After our duct blaster evaluation where we check the duct loss through pressure and volume testing. It turns out that the ducts were so bad that they were loosing about 40% of the air to the outside, with the return duct loosing 22% of that. What was happening was they were bringing in outside warm moist air and cooling that and then trying to get it back into the living areas of the house.
They opted to have the attic sealed, to save heat and cool air, Had the ducts sealed and repaired where needed. And are now looking into a new smaller AC system as they no longer need such a large system to bring the air temps down in the house as they once did.

on Aug 03, 2011 · Like 0
Paul M Fairburn, GA

Victor I just finished redoing all the duct work in a foreclosure home that sat vacant for 5 years. It was so full of dog hair on the returns that I am surprised that any air could move through there at all. It looked as if they ran the unit without a filter because the supplies were lined with a lot of dirt too. It was a real mess. It will be well worth it to know that everything is clean and working properly. Then all you have to keep up with is a good air filter. When I was researching ...»
HVAC systems one recurrent theme kept popping up. Systems being destroyed because of people not changing their filters or running their systems with out a filter at all. I can't understand why anyone would do that. The cost of a filter versus the cost of the system isn't even close to comparison so it just doesn't make sense to me not to maintain your investment. Maybe some people just don't know that, I'm not sure.

on Aug 03, 2011 · Like 1
Woodbridge Environmental ... Colonia, NJ

Paul your right on with this. The biggest killer of an ac system is dirty coils and lack of air flow through them. Filters are cheep and saves more in energy then they cost to replace.

on Aug 03, 2011 · Like 0
Victor R

thanks for your comments guys - we'll see on Monday with the AC man says about getting the project done. I'll try and post some pics after the fact.

on Aug 05, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

Here is some photos of a client of ours who has had two condensing units replaced within the past three years. We were called in to find out why the 2nd one was acting up. Not one AC contractor even looked to see what the condition was with the evaporator coil. All they were interested in doing was to sell the equipment.
One photo shows a filter that is installed in the unit. This filter was only 1 of the two that ...»
were in the system. A prior contractor installed a filter grill in the house but never removed the one within the air bower cabinet. The biggest cause of AC failure is plugged coils.
on Aug 06, 2011 · Like 1
Paul M Fairburn, GA

That is sort of what mine looked like before I cleaned it out. Of course I was swapping out equipment in the process. We did 100% clean and replace.

on Aug 06, 2011 · Like 0
Victor R

Well, we had an AC company come out last Monday and he wouldn't touch it. As it turns out the Evap coil is the original and therefore ~25-30 yrs old. He was afraid that the coil would crack and leak. Also, there is no access panel and he was afraid to cut above the blower unit to access the coil.
He did run a test on the system from outside and told me that he didn't see any pressure ...»
issues, therefore didn't think the coil were dirty. Is that an accurate statement?
Looks like I might be at a dead end. I plan to try and see about accessing the coil through the unit maybe with the shop vac - if I can get to it.

on Aug 15, 2011 · Like 0
Paul M Fairburn, GA

Well having good pressure doesn't mean that your coil isn't dirty. If it is as old as you believe it to be unless someone was very meticulous about filter changes and used a better filter than the fiberglass ones it is hard to believe that the coil isn't dirty to some degree. If you pressure is good and you don't want to really mess with the system I would talk to a duct cleaning company. They have better equipment than a shop vac and it is designed for removing dust. Possibly they can ...»
reverse pressure the system and blow any accumulated dust/dirt out of the coil backwards and at least improve its condition some. If you can afford it, it would not be a bad idea to clean your ducts as well. Accumulated dirt is a killer for a system in the ducts as well as the coil. Good luck with this chore it is not an easy one for sure.

on Aug 15, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

The AC company was lazy. They did not want to touch it because last person that does ends up being responsible for it.
Of course the charge would seem OK. When charging a system its adjusted based on the current conditions both the indoor and outdoor coils sees. So if the coil is partly plugged with dust it will only allow for a set amount of liquid to be converted back to a gas. So therefor the charge would ...»
be set at a lower level then that of a coil that was clean.
Coils will not crack and leak. Cleaning a coil does not mean that they will need to disturb it to much when cleaning. They need to open up the plenum, pull coil out so the bottom can be seen. Then they spray a coil cleaner that foams out the soil between the fins. Once that works for a while, they then spray water to wash the soil out.
The home owner can vacuum the coil if its matted just be careful not to bend the fins or kink the copper lines that feed it.
How is the air flow? If it seems low then the coil should be checked. If the blower is dirty it too can be a indication of the current condition of the coil.
Using a mirror you can sort of lift the coil up a bit and look under it to see if its worth cleaning or not.
Bob

on Aug 18, 2011 · Like 0
Paul M Fairburn, GA

Woodbridge if it is a typical split system how are you going to pull the coil out when it is soldered to the liquid line and the suction line? Typically when cleaning is done the coil is not removed unless it is absolutely necessary. Because that is more work that is needed and the chances of having an error are greater. Not to mention that once the system is opened you will have to re-lubricate or even change the compressor oil, as some will have been lost in the removal of the coil and ...»
the line dryer/filter will have to be replaced as well. If you want to use the blower as an indicator of system cleanliness usually those are easy to remove due to the anticipation of the manufacturer that the blower will have to be replaced at some point during the systems life.

on Aug 19, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

This would depend on what and how the suction and liquid line was installed. Most use a soft copper line set that will move enough to gain access.
Also because of the age of the system it is most likely a soft copper system and not a hard piped coil.
Cleaning of the coil is only necessary if it has plugged due to poor filter service. If the ...»
fan blades have collected enough dust to build up in the air scoops most likely the coil could use some cleaning itself. Or at least needs a look see at its condition.
I would agree with you there is some risk to this, but if the contractor understood what he or she was doing this risk is low.
Most blowers last more then the lifetime of the furnace or air handler. However if the fan does become plugged with dust it can become unbalanced and that alone will cause the bearings to wear out.

on Aug 20, 2011 · Like 0
Harold M Franklin, NC

Thanks for this reminder. I need to clean mine

on Aug 20, 2011 · Like 0
Paul M Fairburn, GA

Most use a soft copper line that is soldered to the evaporator coil and you can't move it very much without kinking or breaking that line. In other words you can't take it out.

on Aug 20, 2011 · Like 0
Woodbridge Environmental ... Colonia, NJ

Once again, it depends on how the line was run to the coil and the experience of the contractor doing the work I have on many occasions pulled coils out sufficiently enough to clean and re-install without damaging any lines or causing leaks. But you must be careful and have a 2nd set of hands handy to help hold and secure coil so it can be cleaned.

on Aug 20, 2011 · Like 0
Paul M Fairburn, GA

We'll you'll just have to demonstrate this technique as I don't know anyone who has ever successfully pulled that off without opening the system and disconnecting the lines.

on Aug 21, 2011 · Like 0
Sherrie S Debary, FL

I believe it is well worth the cost to have a yearly service done by a professional. My job, which I do well, is to keep the filters clean.

on Nov 21, 2011 · Like 0