# 13 seer vs. 15 seer hvac. Is it worth the money?



## IWantPavers

Is The extra $800 for a 15 seer carrier worth it? I need a 3.5 ton heat pump and I'm not sure that It will make a difference going from a 13 seer to a 15 seer. Your thoughts.


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## Inner10

I decided against paying the extra for my house; too long of a payback...but I only have a little guy.


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## flashheatingand

You live in an area in which the heat pump will run year-round. Granted, I know how to spend other peoples money. But, I would step it up. Are you going to get a variable speed air handler or not?


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## IWantPavers

I am in va so it will run heat for about 3 -4 months. It has the option of variable speed


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## flashheatingand

3-4 months heating and i suspect 3-4 months cooling right? I lived in ms, and recall many hot days through mid october.

I just would think the appliance would be used a lot, so, for that reason, I believe it would be worth spending the extra money. Generally, I think a lot of that stuff is just a bunch of marketing hooey. But, based on my prejudices of southern climates, I would step it up some.


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## Doctor Handyman

I know nothing about this but find myself in a similar position for a rental. 

Does anyone know of a chart based on typical usage and current energy rates what the return on the upgrade would be and how long it would take? For example, If the 15 seer cost $800 more but saves $8/month in one year = $96/yr. Therefore it would take 8.3 years to break even. I'm just guessing at the numbers. Is that an unreasonable time frame?

I would think the manufacturers provide this info. Like the yellow Energy Star tags on new appliances.

I'm sure marketing has something to do with it, but isn't there actually real science behind improved efficiency?


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## SLSTech

Doc - Sure we can model the savings, but it all comes down to how you use it. If you keep the house really cool all the time, you would save more than the savings predicted & vice-versa

In short I would definitely get it based on your area whereas in Inner's area it probably wouldn't make as much sense

The other big questions - is it sized properly & how are the ducts? I can't tell you how many places I see where they have replaced the units & are still not comfortable as half the air is blowing into their attic, etc...


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## Builder Butch

Seer ratings are like mpg on autos. Kinda depends on how much you drive to calculate savings, also depends on a good many varibles on the quality of the install ie return air, duct leakage ect. Good science on it but more difficult to calculate savings due to veribles inmvolved.


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## Doctor Handyman

SLS and Butch both made excellent points. Thank you, I understand.

HVAC is a science to be well studied. That is why I sub it out.


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## beenthere

The below link may help you.

http://www.hvacopcost.com/


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## CompleteW&D

Back when I sold residential HVAC, our owner was adament on me doing proper load calculations, duct work inspections and air flow evaluations before ever recommending any equipment. The theory was, if everything was properly sized, the ductwork in order and airflow was well balanced, the new system would perform extremely well, last a lot longer and actually help a customer reduce energy usage.

Many of my competitors were poorly trained on the technical side of things and just pushed high dollar stuff and rarely did any major inspections or calculations. They just replaced like sized equipment to what was there, slammed it in and moved on.

I was the last guy in on one job I went to. I remember quite clearly that he had an older 2-1/2 Ton A/C system and a 100,000 btu furnace. It was a 1400 sq ft ranch on an insulated crawl space with R-13 walls and about R-19 (6") in the ceiling. The windows had been replaced with vinyl double pane glass with Low E. The furnace was in the garage with a single central hall return. For SOME unknown reason, for the bathroom supply run, they had used a 6" round duct and pulled it off the end of the trunk line. Plus, they had used a metal return duct in the attic with no insulation. The attic return was rusted through in several places pulling a portion of the return air right from the attic.

The first words out of they HO's mouth when I got there was: "I want to upgrade to a 3 Ton AC system." When I asked him why, he said he never had enough cooling and the old cooling system ran all the time. I told him that I wanted to do some load calculations and check some things first. He said, well - everyone else quoted me a 3 ton system so that's what I want you to do. I said fine.... and went about my work.

Well, you can imagine what I came up with by properly disconnecting the bathroom's 6" run off the end of the trunk, installing a proper 4" run and pulling it off the top of the trunk, replacing the rusted through metal return duct in the attic with insulated flex, and installing supply vent dampers to the two living room runs - which didn't need all the air it was getting.

I determined that a 12.0 SEER 2 ton condensing unit with a 60,000 btu 2 stage gas, variable speed 90% furnace - was MORE than enough to properly heat and cool his home with ease, plus give him much better dehumidification in the summer (with the variable speed blower). I also added in blowing another 8" of celulose insulation into the attic. My quote came in about $900 higher than the other guys who quoted 3 Ton 10.0 SEER (10.0 SEER was the minimum back then) - single stage, 80,000 btu 90% equipment, with no other changes (not even the rusted return in the attic).

When I explained to him that by fixing his airflow and air balance problem in his home, replacing the rusted through attic return with insulated flex, adding 8" of insulation in the attic.... his system would be performing at peak efficiency with less stress on the equipment, and his home would be a LOT more comfortable.

He was extremely dubious, but I finally convinced him to trust me (I think because I was the only one to go into his attic AND crawl space) and we did the install exactly as I spec'd it. He was so estatic on how much more comfortable his home was, he referred us to a bunch of his cronies and we ended up getting about six or seven more jobs from his referrals over the next year or so.

The moral of that long winded story? Properly size the system by doing detailed load calculations and correctly balance the air flow before worring about the cost savings of increased efficiency on equipment. Efficiency won't matter if the system balance and loads are all out of whack.

Can you imagine what that 1400 sq ft home would have felt like with a 3.0 ton/100,000 btu system installed??? :blink: Cold and damp - cave city in the summer, with hot and cold spots all over the place in the winter.


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## beenthere

CompleteW&D said:


> Back when I sold residential HVAC, our owner was adament on me doing proper load calculations, duct work inspections and air flow evaluations before ever recommending any equipment. The theory was, if everything was properly sized, the ductwork in order and airflow was well balanced, the new system would perform extremely well, last a lot longer and actually help a customer reduce energy usage.
> 
> Many of my competitors were poorly trained on the technical side of things and just pushed high dollar stuff and rarely did any major inspections or calculations. They just replaced like sized equipment to what was there, slammed it in and moved on.
> 
> I was the last guy in on one job I went to. I remember quite clearly that he had an older 2-1/2 Ton A/C system and a 100,000 btu furnace. It was a 1400 sq ft ranch on an insulated crawl space with R-13 walls and about R-19 (6") in the ceiling. The windows had been replaced with vinyl double pane glass with Low E. The furnace was in the garage with a single central hall return. For SOME unknown reason, for the bathroom supply run, they had used a 6" round duct and pulled it off the end of the trunk line. Plus, they had used a metal return duct in the attic with no insulation. The attic return was rusted through in several places pulling a portion of the return air right from the attic.
> 
> The first words out of they HO's mouth when I got there was: "I want to upgrade to a 3 Ton AC system." When I asked him why, he said he never had enough cooling and the old cooling system ran all the time. I told him that I wanted to do some load calculations and check some things first. He said, well - everyone else quoted me a 3 ton system so that's what I want you to do. I said fine.... and went about my work.
> 
> Well, you can imagine what I came up with by properly disconnecting the bathroom's 6" run off the end of the trunk, installing a proper 4" run and pulling it off the top of the trunk, replacing the rusted through metal return duct in the attic with insulated flex, and installing supply vent dampers to the two living room runs - which didn't need all the air it was getting.
> 
> I determined that a 12.0 SEER 2 ton condensing unit with a 60,000 btu 2 stage gas, variable speed 90% furnace - was MORE than enough to properly heat and cool his home with ease, plus give him much better dehumidification in the summer (with the variable speed blower). I also added in blowing another 8" of celulose insulation into the attic. My quote came in about $900 higher than the other guys who quoted 3 Ton 10.0 SEER (10.0 SEER was the minimum back then) - single stage, 80,000 btu 90% equipment, with no other changes (not even the rusted return in the attic).
> 
> When I explained to him that by fixing his airflow and air balance problem in his home, replacing the rusted through attic return with insulated flex, adding 8" of insulation in the attic.... his system would be performing at peak efficiency with less stress on the equipment, and his home would be a LOT more comfortable.
> 
> He was extremely dubious, but I finally convinced him to trust me (I think because I was the only one to go into his attic AND crawl space) and we did the install exactly as I spec'd it. He was so estatic on how much more comfortable his home was, he referred us to a bunch of his cronies and we ended up getting about six or seven more jobs from his referrals over the next year or so.
> 
> The moral of that long winded story? Properly size the system by doing detailed load calculations and correctly balance the air flow before worring about the cost savings of increased efficiency on equipment. Efficiency won't matter if the system balance and loads are all out of whack.
> 
> Can you imagine what that 1400 sq ft home would have felt like with a 3.0 ton/100,000 btu system installed??? :blink: Cold and damp - cave city in the summer, with hot and cold spots all over the place in the winter.


He would have thought he was going through menopause in the winter, and probably would had to set his stat to 66 in the summer to try and get the RH down, and paid twice as much to run the 3 ton as he was to run the 2.5 ton. 

Nice work.


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## CompleteW&D

beenthere said:


> He would have thought he was going through menopause in the winter, and probably would had to set his stat to 66 in the summer to try and get the RH down, and paid twice as much to run the 3 ton as he was to run the 2.5 ton.
> 
> Nice work.


Thanks.... By balancing the airflow, adding insulation, fixing the return and going variable speed.... he got WAY better dehumidification in the summer. With the higher efficiency unit, operating to spec, he was astounded how much higher he could set the thermostat in the summer to keep the cooling level where he was comfortable.

Same thing in the winter months. I always loved selling 2 stage gas - variable speed units. With proper air balance, those systems kept a constant temperature throughout the house really well. People found that they could lower their t-stats a few degrees and maintain or even increase their over all comfort levels. :thumbsup:


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## flashheatingand

So, where do you guys set the stat during the summer, with an setup that is money (Those of you where humidity is a major issue)?


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## beenthere

I have my blower slowed to 280CFM per ton, and keep my place at 72, I like it cold. 

I have customers that set their stat at74 with VS blowers and they say it feels colder then when they kept it at 72 or 70 with their old over sized PSC blower system.

Are temps are not severe, but we run 65% plus OD RH very often.


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## ACrepairantioch

*Hvac*

That's the only brand we recommend is Carrier. Unfortunately with California regulations even those don't last now.


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## Dr Heat

I do not have typical Air Conditioning. Ammonia is king.


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