1. It's reasonable, but I do suggest you get 2-3 quotes for the job. Without a variable-speed furnace, you'll likely get less than 14 SEER. The XR13 might be a better choice at a lower price. Trane isn't the only good product out there either.

2. The lineset doesn't need to be changed in all cases, but when it can be done financially and physically, it's never a bad idea. Most of the time (unless something major like a compressor burnout occurred), if the lines are the right size, flushing the lines or purging them with nitrogen and pulling a good vacuum is sufficient. Refer to the manufacturer's recommendations. I don't know of one that requires replacement.

3. Heat pumps are sized for cooling, not heating in most cases. You have a furnace as backup heat anyway. With heat pumps, if your load comes to 43k btu's, I would say it's fine to go with a 4-ton unit, and in fact that's probably what I'd suggest. The 3.5-ton unit may not handle your heat load at design conditions, and the units are rated with a thermostat setting up 80* (setting it lower would increase cooling needs). It is GREAT that your contractor did a load calculation.

I do suggest forgoing the coil replacement idea and going with a new matching system.

I'd be concerned upsizing at all: You haven't said the old unit couldn't keep up, just that the lone "salesman did a load calc". As I understand it you have three tons now; based on the jobs I see, it's probably oversized. I'd be looking at the existing ductwork and fixing any leaks, reinsulating any metal duct, and thinking about downsizing if anything.

The heat pump is a good idea, it'll be quite inexpensive down to around freezing; then you'll switch over to gas and have the same heating comfort you've always enjoyed.

I wouldn't take a chance on cleaning the lineset; that's all about workmanship.

Definitely want to make sure your ductwork system can handle 4 tons of airflow. Many duct systems are undersized to begin with. Make sure your dealer determines that you have ample supply and return for 4 tons.

Sorry, I forgot to mention that the previous unit was struggling somewhat to keep up with the cooling.

So I get a call from the guy, and he says he can't get the XL14i for another day. He can get me the XL15i in a 3.5 ton unit today. Since I'm going up a bit in SEER but going down a bit in tons, the price comes out basically the same. Should I go this route? Like I said, my heat gain is 43,000. If I understand right, the 3.5 ton unit can handle 42,000. This is awfully close, and the old unit wasn't struggling THAT much.

My other option that I can get today is a 3.5 ton XR13. It would save me a few hundred bucks. I don't have variable speed, anyway, so does the XL15i really give me any benefit, other than being a little quieter and having a better warranty on functional parts (10 years rather than 5)? Both have 10 years on the compressor.

Thanks for your help!

I talked to the guy again, and now he's finding out there would be a problem with getting the right coil for the XL14i. He MIGHT be able to install on Thursday, but there's also a chance it wouldn't be until Friday.

He found out there's an R22 version of the XL14i in stock right now. Other than environmental concerns, is there any real problem with using the R22 instead of the 401A?

Go with the properly-sized system. Sounds like 4 tons is what would be best for you, if your ductwork has been inspected and found to be able to handle 4 tons of cooling and heating from the heat pump. If not, it won't run efficiently or provide the proper cooling and heating. I personally recommend R-410A right now, but there is nothing wrong with going with a R-22 unit. Sometimes R-22 is preferable (hot rooftop applications, etc.). R-22 is being phased out, but availability shouldn't be a concern. Who's to say the R-410A price won't skyrocket once the demand increases? The R-22 price has been on the rise. 4-ton XR13 sounds like the best route in my opinion, R-22 or R-410A. However, the R-410A XR13's tend to have better heating capacities and come with a scroll compressor in the 4-ton size, whereas the R-22 version only has a scroll compressor in the 5-ton size.

schmidt

first to answer your last post.

unless this is an emergency, I would want an R-410a refrigerant HP with matching coil.

Your situation is not as simple as it might appear.

several questions.

1.your existing AC condenser is three tons? and sometimes at extreme outside temps it does not cool adequately? Pls confirm

2.What is model, size, apprx age of existing furnace?

3.And the blower motor's rated size? Very important. You will have problems if you go up in size with a 3 1/2 ton HP with a furnace that has only a three ton rated blower motor.

I hope you realize that with the XL14i or XL15i you will not achieve its rated eff/performance potential with a mismatched non var speed furnace. Anyone who says otherwise is simply blowing smoke. If you go from a three ton to a 3 1/2 ton, your ductwork has to be sized correctly for good airflow. This should be verified.

Trane HPs while very reliable but are light in heating BTUs for its rated size-all but the XL15i. Just so you know.

For me, the XR13 or XR14 HPs in R-410a would be better choices than the XL models unless you intend to replace furnace in very near future with a matching var speed model.

There are good options other than Trane such as Carrier Comfort series HPs.

IMO

Tigerdunes, thanks for all your feedback! Below is a point by point response:

For my wife, this may be considered an emergency situation. We have a baby who is not quite six months old, plus two older children. The outside temps are in the 90s this week.

1) Yes, our existing unit is 3 tons. Sometimes it doesn't keep up, even when the outside temp is not that awful (below 90 degrees).

2) Existing furnace is Goodman 100-4. It's 9 years old.

3) Existing blower is rated for 4 tons.

Existing ductwork is substandard. It's a bunch of flex/duct, starting with a 14" main trunk attached to a ductboard box on top of the current coil. Since my house is two stories on a slab, it would be prohibitively expensive to redo the ductwork. The company quoting me says that what matters most is the 4-ton blower, and that I should be fine putting a 4-ton coil on it. They said said they would fabricate a metal plenum which should maximize the air flow from the current blower through the current ductwork.

Does it sound like they're shooting straight with me?

It sounds like the company you're dealing with is competent, but even if you have a blower RATED at 4 tons, the system may not deliver 4 tons of conditioned air if your ductwork isn't up to par. How many return grilles do you have, and what size are they? How many supply registers? The 3.5 ton may be fine, but per your load calculation I would install a 4 ton personally. Why? Because the units are rated at 80 degrees, and setting your thermostat lower each degree increases your cooling requirements. Additionally, I don't like having a system that is even 1000 btu's undersized at design conditions. I would NOT install a 4-ton unit if the ductwork couldn't handle it. I'd rectify the ductwork situation first. It's highly advisable to get more than one bid. I suggest Carrier's Comfort 13 Puron heat pump with matching CNPVP TIN-PLATED coil (10-year warranty I believe) for your situation if you look into Carrier.

Thanks again for all the great feedback!

ryanhughes, I have two return grills, each 20x20. One is directly beneath the furnace, going through the ceiling in my second floor. The other is on the first floor, but doesn't draw air well at all.

I have 8 supply registers on the second floor, and 6 or 7 on the first floor.

Thanks again!

And your dealer doesn't think there is a problem with putting a 4-ton unit in with the ductwork system? I can't see it from here, but your ductwork system seems borderline being able to handle a 4-ton system. So at this time, what is your dealer recommending you do? Stick with 4 tons, or go with a 3.5-ton system? The 3.5-ton system may do just fine and be the better choice for your situation with your ductwork.

schmidt

if you intend to use existing ductwork without taking any measurements or making any modifications, then I would stick with a 3 1/2 ton model. the four ton would be a 33% increase,while the 3 1/2 ton would only be 1/2 that amount.

IMO