Bad Coil - New System Quotes - Need Help

[fcabanski]

This year, about a month ago, a local AC company checked the AC when it wasn't cooling well. The tech said the coil is corroded, needs replacing, but that he could recharge the coolant and see how long I can get along with that.

This company, and others, have told me the unit I have (3.5 ton condenser) is a little too small for the house (2100 sf, two story in TX). He recommended moving up to 4 ton when I replace it.

The other day when it was humid outside (79 temp, 75% humidity) the temp in the house was where I set it, but the humidity in the house was 59%. I called out the same AC guy for a quote on a new system. He recommended a new condenser and coil, and gave quotes on a 3.5 and 4 ton condenser with the new coil.

I called two other companies for estimates. Both poked their heads into the attic, instantly said the coil is leaking, and gave me quotes. The first of these two quoted almost the same price, but said it would be wise to also replace the furnace because the existing one was a little small for the 4 ton unit. His quote including the furnace bumped the price up $.

The third company gave me three options. I know the three option strategy is to get someone to choose the middle option. It so happens that the middle option was very close in price to the other two, but also included a furnace and adding insulation. He also recommended a slab coil, which the first two didn't mention. He tried to get me to buy now by offering to recharge the freon free (for cooling over the holiday). I told him I still wanted to research the quotes and think about. He then recharged the refrigerant anyway. That was pretty good.

Here are the quotes (minus pricing info...the prices are very close) from the first guy and the middle option third guy.

4 Ton 14.5 Seer Ruud 410A Condenser
Matching (4 ton) Box Coil, Transition Plenum
Along with access door, pan, drains and a float switch
Balance the system so all rooms cool evenly.
No mention of a furnace.
10 year compressor
10 year parts
5 year labor


Comfort Maker brand
Condenser cxab48gka (4 ton, 16 seer)
Furnace g8mxno901210
Coil EHD4x60al
Add insulation to attic for R44
retro fit ducts and add dampers
2 years of company's yearly system check free (pre-summer for condenser and coil, pre-fall/winter for furnace)
10 year compressor
10 year parts
5 year labor
5 year replacement limited warranty

Other questions:

Do I have to replace the condenser? Even though it's a little under sized, it works. The issue is even when the house was new the AC had trouble cooling it during the 90+ degree summer days?

The concern with the middle quote, third guy is it seems to be quoting a lot more for about the same price. He also mentioned that his yearly inspection service is required as they have to keep maintenance records to comply with the warranty. I don't like the sound of that. But overall, what's the catch? Why does it seem like more for the same price?

The high end quote from the third guy is about 25% more, but includes a two stage unit and separate controls (he claims) for temp and humidity. It seems to be overkill to me.

Comfortmaker
Condenser: ccA748gka (17 seer, 4 ton)
Furnace g8mvc0901716
Coil ehd4x60al
Retro fit ducts and dampers
Add insulation to R60
3 years of free inspection service
10 year compressor
10 year parts
5 year labor
10 year replacement limited warranty

[beenthere]

Trouble cooling the house when its 90 plus outside? Does that mean it couldn't hold set temp, or that it just ran for long long periods of time.

At 3.5 tons for 2100 sq ft, you have 600 sq ft per ton, which is usually more then enough, except in those areas that often reach over 100, or homes with little insulation.

[catmanacman]

AT 2100 square ft 2 story is the upstairs hotter than the downstairs

[fcabanski]

Mistake on sq foot...it's 2450.

Yes, upstairs is often hotter than downstairs.

It could hold set temp, but when set temp was achieved the humidity in the house was 59%.

There is a leak in the coil. Three AC companies verified it. The air blowing out of the vents isn't cold enough.

[Mr Bill]

4 Ton 14.5 Seer Ruud 410A Condenser
Matching (4 ton) Box Coil, Transition Plenum
Along with access door, pan, drains and a float switch
Balance the system so all rooms cool evenly.
No mention of a furnace.
10 year compressor
10 year parts
5 year labor


If this co. is a Ruud dealer, they need to get into the 21 century on the warranties, you also get "if you register online" a 5-year complete condenser replacement warranty. :grin2:

[fcabanski]

It is a condenser warranty. Calling it labor was my mistake.

[tinknocker service tech]

did any of then do a load calc on your house

going up in size isnt always the right thing to do and will not solve you problem with the second floor

keeping up and holding temp at 59 percent is leading me to believe you have other problems either with the house leakage or sizing problem

zoneing may be your best option with a properly sized system

[Mr Bill]

The third company gave me three options. I know the three option strategy is to get someone to choose the middle option. It so happens that the middle option was very close in price to the other two, but also included a furnace and adding insulation. He also recommended a slab coil, which the first two didn't mention. .

The Ruud guy did not offer the slab coil, because you have to use the box coil "which is a good coil" to get the 5-year condenser replacement from Ruud. In Houston we have many, many happy customers with the single stage 14.5 seer Ruud system.

[fcabanski]

Yes, but which configuration is better? The prices are similar. Is it just a matter of opinion?

Is the box coil better than the slab coil? The third guy said the slab coil is much better.

Is more insulation and the systems mentioned a better value, or is he throwing in the insulation because overall that system isn't the same quality as Ruud?

Before the coil leaked the house cooling and humidity were ok, except for some rooms being hotter. When the coil leaks, and before recharging, the AC does not cool the house well.

Since none of the three performed a load calc, should I call for more estimates until I find someone who does it?

[Mr Bill]

The third guy said the slab coil is much better.


Did he offer an explanation for his opinion?

[udarrell]

did any of then do a load calc on your house

going up in size isnt always the right thing to do and will not solve your problem with the second floor

keeping up and holding temp at 59 percent RH is leading me to believe you have other problems either with the house leakage or sizing problem

zoning may be your best option with a properly sized system
Agree, either unit is not working at full capacity or, there is a lot of hot air infiltration; unless you live in high humidity area, - it should usually get the humidity down to at least 50%.

What large city do you live near in TX?

[fcabanski]

I'm in Houston. Humidity today outside is 64%. It's been over 70% lately.

If these guys are just quoting new systems without calculating load, without examining reasons for humidity higher than 50%, who can I find in the NE Houston area who will do those things?

[Mr Bill]

I'm in Houston. Humidity today outside is 64%. It's been over 70% lately.

If these guys are just quoting new systems without calculating load, without examining reasons for humidity higher than 50%, who can I find in the NE Houston area who will do those things?

Start with a home energy audit, it is the first step in making your home more efficient. An audit can help you assess how much energy your home uses and evaluate what measures you can take to improve efficiency. But remember, audits alone don't save energy. You need to implement the recommended improvements. Then find yourself someone to do a Load calculation Manual J and a Manual D on your home, you need both the home energy audit and the load calculations, one without the other is just throwing dollars out the window. Manual J and a Manual D do you no good if air is escaping, or being drawn into your home.

[fcabanski]

Do HVAC companies, good ones, do the MJ and MD as part of quoting a new system?

[Mr Bill]

Do HVAC companies, good ones, do the MJ and MD as part of quoting a new system?

Most any of them will do a load calculation after you sign a contract. The reason a lot won't upfront, is it takes a lot of time to do one correctly, and if they don't get the job, and they just paid a man $35.00 per hr. for example, there just went a hundred bucks out the window. I would not categorize an a/c company as "good" on just one aspect of the business, what if you got a load calc. and the installation looks like 10 year old kids did it? :grin2: Again, you need an energy audit first, load calcs. don't stop walls and windows from leaking. :grin2:

[udarrell]

I'm in Houston. Humidity today outside is 64%. It's been over 70% lately.

If these guys are just quoting new systems without calculating load, without examining reasons for humidity higher than 50%, who can I find in the NE Houston area who will do those things?
Well, that high outdoor humidity makes it a lot more difficult to keep it at 50% indoors, unless air infiltration is held to a minimum.


Mr Bill: Start with a home energy audit, it is the first step in making your home more efficient. An audit can help you assess how much energy your home uses and evaluate what measures you can take to improve efficiency.

But remember, audits alone don't save energy. You need to implement the recommended improvements.

Then find yourself someone to do a Load calculation Manual J and a Manual D on your home, you need both the home energy audit and the load calculations, one without the other is just throwing dollars out the window. Manual J and a Manual D do you no good if air is escaping, or being drawn into your home.
Hey Bill, Man you're hitting Grand Slam Home Runs with your Posts! Keep swinging that Big Bat...we need to reduce energy use; today & the next two days up here in SW WI we're getting 110 to 115F Heat Indices.

Had Record Setting June Temps &, now end of June & into July, week long above 90s with quite high Heat Indices.

My little First Floor 6,000-Btuh Half-Ton 9.7-EER Whirlpool window Unit has humidity at 50% & temp @75F; should keep it within 78F rest of day & into the night. A floor fan circulates the air, what a low power consumption setup.

All electric home for summer cooling, total bill, including big dehumidifier in basement, for record setting month of June used 470-KWh * .0985-cents (nearly 10-cents a KWh)= $46.295. Yep, It's Magic...:grin2: :whistle:

[fcabanski]

I keep the house at 80 degrees in the summer.

Since the last guy recharged the coolant the house is comfortable, but indoor humidity is still at 55%.

When it leaks for awhile it becomes uncomfortable at 80 degrees, 60% humidity, and runs a lot longer to maintain 80 degrees.

I have scheduled an energy audit, and then will find someone to perform those other tests.

I still will need a new AC or at least a new coil. I'd still like to know if replacing the condenser and furnace is necessary if the coil is leaking.

How about a mini split system? It would be nice to only cool rooms that are in use rather than the whole house.

[Mr Bill]

Hey Bill, Man you're hitting Grand Slam Home Runs with your Posts! Keep swinging that Big Bat..

Well that is because I found a way to compromise. :grin2: I know the LC bunch have been pushing the LC here forever, and I do condone the LC, but are we really doing the customer any justice by pushing the LC and not the energy audit? I personally don't think so. For the very best of both worlds, the customer needs to have both done, like I said, I have never seen a LC that fixed air leaks.:grin2:

[udarrell]

Well that is because I found a way to compromise. :grin2: I know the LC bunch have been pushing the LC here forever, and I do condone the LC, but are we really doing the customer any justice by pushing the LC and not the energy audit? I personally don't think so. For the very best of both worlds, the customer needs to have both done, like I said, I have never seen a LC that fixed air leaks.:grin2:
Right-On; a Home Energy Efficiency Audit tells you what you can do to lower the Load Calc (LC) &, most times reduce the size of the equipment, that is also where the most energy savings, summer & winter, can be realized.

Therefore, especially on larger tonnage systems, by being enabled to reduce the tonnage, the duct system-airflow & everything performs a lot more efficiently &, the system much closer to its nominal performance rating.

[fcabanski]

Sears, of all people, offered the J and D tests as part of quoting a new system. I told them their system prices were too high, but they still performed the tests. They concluded 4 tons, and said the current coil (4 ton) and compressor (3.5 ton) mismatched likely cause the system to run inefficiently. The software spit out 4.4 tons, but they said because of the house design (the top floor only goes half way across the house width) it would really be a 4.

They offered a quote for a coil and compressor - Kenmore 4 ton, two stage, that's a little more than the first two quotes mentioned in the original post. Sears also said the insulation in the attic, and the furnace are fine.

Centerpoint still hasn't gotten back to me about the energy audit, but it is scheduled.